CMC based composites for wastewater treatment.
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Article Type: Review Paper
Date of acceptance: May 2025
Date of publication: July 2025
DoI: 10.5772/geet.20250012
copyright: ©2025 The Author(s), Licensee IntechOpen, License: CC BY 4.0
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This review deals with carboxymethyl cellulose (CMC) and poly (acrylic acid) or PAA based composites and highlights their applications in wastewater treatment. These composites have drawn considerable attention as sustainable materials for wastewater treatment because of their exceptional structural adaptability, biodegradability, and high adsorption capabilities. Composites, broadly categorized into oxide based, hybrid, biosorbent, nanocomposites and polymer composites, are designed to improve specific functional characteristics for targeted purposes. The process of esterification is used to synthesize CMC, offering excellent hydrophilicity, biocompatibility, and chemical reactivity. CMC based composites exhibited superior adsorption potential for organic pollutants, heavy metals and various kinds of dyes, driven by presence of many hydroxyl and carboxyl groups. PAA composites are very successful at removing pollutants due to their strong ion-exchange capabilities and pH responsiveness. The blends of CMC and PAA further amplifies the adsorption efficiency by combining the anionic nature of PAA and hydrophilicity of CMC. In few cases, efficiency in reducing the pollutants level was greater than 90%. This comprehensive review demonstrates the effectiveness of composite materials for contaminant mitigation over conventional individual materials. It also highlights recent advancements, discusses their key derivatives and their environmental benefits as eco-friendly and cost-effective materials for wastewater management.
biosorbent
composites
wastewater treatment
water pollution
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Water is essential for life on Earth and has played a crucial role in the development of human civilization since ancient times. Ensuring that everyone can access safe and affordable drinking water remains a significant global challenge. The rapid pollution and damage to our natural water sources are serious problems that require immediate action to safeguard the planet and its people for the future [1, 2]. In recent years, new technology has rapidly grown, leading to pollution of several water sources. This has led to major environmental and increased pollution problems [3]. Although there are many ways to pollute water, dye contamination from industrial effluent discharge is a significant source. Paper, skincare products, leather, colorants, petroleum, textiles and clothing, plastics, refineries, printing processes, medicines, and food processing are few industries that generate these effluents [4–6].
An estimated 20% of global water usage is reserved for industries, which also continuously release a variety of pollutants into water bodies, harming ecosystems irreparably. Heavy metals are also among the contaminants that are frequently released into environment via effluents derived from manufacturers and human activities [7]. In addition to damaging the ecosystem, water pollution may aggravate air pollution, which is extremely dangerous for human health. It also harms the social progress and economic growth of the impacted communities or countries. The supply of fresh, clean water has become a global concern in the twenty-first century, as reported by United Nations recently, since polluted water endangers the existence of all organisms that exist [8, 9]. As stated by the World Health Organization, around 1 million deaths occur every year as a consequence of drinking tainted water. Additionally, four billion health cases related to aquatic infections are reported each year [10].
Contaminated water implies that harmful things are present in the water, making it unsafe to drink or use. Numerous chemicals, physical, and mechanical techniques are available to solve this expanding problem. Researchers are also still looking at cutting-edge technology to improve water purification methods at a lower cost [11, 12].
Many common ways to treat wastewater, like using chemicals to separate waste, special membranes, exchanging ions, and electrical treatments, have limitations for implementation at scale. Thus, these techniques are frequently inappropriate for practical applications involving the treatment of large volume of water. The use of reusable materials and simply, less expensive methods that save time and money are preferred [13–15]. Adsorption techniques offer an easy, affordable, and efficient way to remove heavy metal ions. Of late, there has been an increased interest in studying this approach. In the adsorption process, a material that may draw in and retain pollutants is combined with contaminated water. This occurs through certain regions on the surface of the substance, and it continues until all of these regions are occupied [16]. The ideal adsorbent should have the following characteristics: many active sites, a large surface area, biodegradability, and ease of manufacture and availability, for an adsorption process to be both effective and feasible [17]. Polymer-based nanocomposite adsorbents are particularly effective in decontaminating water. For adsorption purposes, synthetic polymers alongside biopolymers materials have been considered [18, 19].
Natural polymers, such as polysaccharides, have received a lot of interest in wastewater treatment because of their environmental benefits. Polysaccharides which include starch, chitosan, alginate, and carboxymethyl cellulose (CMC) are commonly used as excellent adsorbents in wastewater treatment due to their low cost and environmental impact [20].
In this context, the study of new compounds with customizable physicochemical properties has become crucial, with polymer-based materials emerging as a potential replacement.
The synthesis of carboxymethyl cellulose-acrylic acid (CMC-AA) composites integrates the beneficial properties of both materials, leading to multifunctional systems with improved adsorption efficacy, thermal sustainability, and mechanical strength.
This review provides an in-depth analysis of the manufacturing, properties, as well as the use of the CMC-AA composites in wastewater treatment. By integrating previous data, this study evaluates their performance in various wastewater treatment and the mechanisms establishing their pollutant removal capabilities as shown in Figure 1.
Application of composites for wastewater treatment.
A composite material is a solid, heterogeneous medium consisting of a combination of multiple substances that have distinct physical characteristics and are separated by definite interfaces. It is believed that various materials create areas that are sufficiently large to be considered as continuous media. Any areas composed of material with identical physical characteristics are referred to as a phase. The complete set of phase interfaces is referred to as the phase geometry. The physical properties of a heterogeneous medium obviously depend upon the physical properties of the phases and the phase geometry. Unlike phase geometry, the physical properties are quite simple to define. Real materials have extremely irregular phase geometries [21].
The implementation of composites in decontamination of water is gaining interest among scientists. Exceptional strength, ease of processing and design versatility are the standout features of composites [22].
The efficacy of the oxide-based composites in wastewater treatment has been elucidated. The large surface area and substantial pore volume of graphene oxide composites permit effective removal of impurities. Consequently, these composites have been used to remove pollutants in agriculture and the textile areas [23]. Nano-iron oxide reinforced MWCNT hybrid composite that incorporates multi-walled carbon nanotubes and iron oxide, was analyzed for its ability to remove Cr (III). A magnetic phase was detected by XRD, and the iron oxide’s attachment to the MWCNT network was shown by FESEM. The results of the comparison with activated carbon showed that the batch mode showed more promise. Batch experiments were primarily governed by pH values, exposure time and mixing speed, but in fixed bed experiments, column bed depth and liquid flow speed were more decisive factors. Apart from offering surface area for adsorption, the composite also helped remove magnetic impurities. Particles of GO, containing oxygen, induce a negative charge on composite, making it susceptible to interactions with cationic impurities via electrostatic bonding. Iron oxide coated zeolites (IOCZ) have also been used to create composites for copper (II) removal and water purification [24]. Adsorption energy (E) ranged from 10.310 to 21.321 kJ/mol and the composite demonstrated high efficiency in adsorbing Cr (VI). The findings indicated that ion replacement and alteration of surface were the primary approaches driving the purification method [25].
A novel hybrid composite, Ch-nHYCA 1:5, was synthesized by combining kaolinite clay, seeds of Carica papaya, along with various additives (Alum, ZnCl2, chitosan, NaOH) using surface modification and solvothermal methods. This composite effectively disinfected water, demonstrating significant removal of specific species of bacteria within 120–270 min of contact time, achieving better bacterial reductions. The highest retention efficiency was evaluated using the Brouers-Sotolongo and Sips models [26].
In 2012, Bai et al. developed a one-pot solvothermal method for synthesizing hybrid materials incorporated with graphene oxide having reduced functional groups and Fe3+ and M2+ ionic species. Different characterization techniques were utilized to analyze the synthesized materials. The resulting composites exhibited low remanence and high saturation magnetization. Notably, a 0.6 g/L concentration of the material demonstrated efficient elimination of MB and rhodamine B dyes, achieving 100% and 92% removal, respectively, from 5 mg/L solutions within 2 min. Furthermore, the composites exhibited significant photocatalytic activity in the dye breakdown procedures [27].
It has been shown that hybrid composites are useful for quickly eliminating dyes from wastewater.
Valentina & Shankar (2015) described in detail the various types of biosorbents investigated for the purpose of decontaminating water. Composites have been used under a few general headings, such as inorganic particles in chitosan [28–36], alginate [37–39], cellulose [40, 41], and polymer matrices [42].
A chitosan/clinoptilolite composite was synthesized and evaluated for the exclusion of Co2+, Ni2+, and Cu2+ ions from aqueous medium. The highest adsorption capacities for these metal ions were also investigated. Factors such as pH values, ion density, and thermal parameters significantly influenced the adsorption process. The pseudo-second-order model was found to best fit the adsorption process in kinetic studies, surpassing intra-particle diffusion model. Thermodynamic analysis indicated the spontaneity of adsorption process, as indicated by Gibbs free energy values. To assess the reusability of the adsorbent, desorption studies were conducted using 0.1 M HCl, successfully eluting the adsorbed metal ions [29].
Nanocomposite is a multiphase material formed by combining a standard matrix material with nanoparticles. Due to their high surface-to-volume ratio, nanoparticles significantly enhance properties of the base matrix—be it metal, polymer, or ceramic—when integrated into the composite materials. Nanocomposites have gained interest from environmental experts and specialists in the domain of water purification. This interest is driven by their large surface area, superior adhesive properties, thermal durability, outstanding structural performances, effectiveness in micro pollutants eliminating capacity, antifouling functions and economic advantages [43, 44].
A ceria nanocomposite structure was created to solve the problem of water remediation; which can remove carbon monoxide and other water contaminants [45]. Through the generation of heteroagglomerate comprising anatase and maghemite nanoparticles in a neutral pH environment, Darko Makovec et al. accomplished the elimination of pollutants from wastewater using photocatalysis [46].
The elimination of lead ions and organic dyes was assessed using metal–organic frameworks (MOFs) composite derived from zirconium. Studies have shown that even after six desorption cycles, the composite’s regeneration efficiency remained unchanged [47].
Polymers possess diverse and notable properties such as targeted functionality, heat resistance, adhesive properties, and manufacturability, positioning them as a practical solution for wastewater management and ecological restoration. The exploration of polymer-based nanocomposites have gained considerable attention in scientific research. The development of these composites with tailored properties has enabled effective environmental restoration projects. Their performance in water treatment is governed by surface catalysis, adsorption proficiency and physical features. However, natural fiber polymer composites have the drawback of moisture absorption, which weakens the fiber-polymer bonding within the polymer. By chemically treating fibers, the strength and performance of fiber-embedded polymer composites are enhanced, mitigating this challenge [48–51].
A synthetic polymeric composite with embedded nanocrystalline cellulose was successful in removing Fe (II) from contaminated water. The findings established the stability of chelation capabilities of Fe (II) in acidic and alkaline environments, and Fe (II) existence in water was associated with turbidity, microbial development, and an unpleasant taste [52].
A novel composite was developed by incorporating clay with a polymer blend of acrylamide and acrylic acid, through cross-linked polymer formation process. This composite demonstrated potential for the effective decolorization of bromophenol blue from contaminated water [53].
CMC is a water-soluble anionic form of cellulose, consisting of linear chains of polysaccharides composed of anhydro-glucose units linked by 𝛽-1,4-glycosidic bonds. The addition of carboxymethyl groups (–CH2COOH) in CMC substitutes certain hydrogen atoms from –OH groups of pure cellulose, setting it apart from cellulose. The chemical structure of cellulose and carboxymethyl cellulose is shown in Figure 2 [54]. It is a commonly used and environmentally friendly water-soluble polymer. It often contains numerous active functional groups, including hydroxyl and carboxyl, which are suitable active sites for adsorption [55]. Despite being widely used in wastewater treatment, CMC has limited strength and adsorption capacity. To overcome these constraints, different physical and chemical modification techniques, including composite development and grafting, have been applied [56, 57].
Chemical structure of cellulose and carboxymethyl cellulose.
There are various sources for obtaining cellulose content for the synthesis of CMC.
The synthesis of CMC from conventional terrestrial cellulose sources require pre-treatments that are costly to implement due to presence of impurities like lignin, hemicellulose and pectin. This has led to shift toward crop residues, including fruit peels, leaves, sugarcane bagasse that provide inexpensive and readily available cellulose content [58]. Thus, in recent years these materials have been used for the production of commercial CMC for a numerous applications.
Meenakshi et al. reported a potential source of cellulose from banana pseudostems [59]. After few years, a commercial grade CMC was prepared from agricultural waste materials [60]. Sago thwacks were later used as precursors [61]. Technical grade CMC carrying versatile viscous characteristics and degree of substitution (DS) values has been synthesized from plenty of waste materials. It proved to be a very promising precursor because of its suitable properties for synthesis of CMC on industrial scale. After maize seeds, it was corncob which was regarded as waste in different parts of world [62]. A study reported that a noxious weed with a variety of detrimental effects on land productivity and, in turn, entire ecosystem biodiversity was a significant precursor for the synthesis of elevated viscosity and average DS value CMC product [63].
In addition to standard plant-based cellulosic sources, frequently utilized domestic and market-generated goods (discarded papers, slurry) and different textile industry waste materials (knitted rags) are mostly available free of cost and can be employed for synthesis of CMC. These waste products lowers production costs and play a role in reducing environmental pollution [64].
Jahan et al. reported an inexpensive, sustainable method for manufacture of CMC from cotton pulp by making the use of different radiations including ultrasonic and microwave [65]. In another study, CMC was synthesized from knitted rags with high percentage of A-cellulose. The authors conducted a seven-step process of carboxymethylation under identical experimental conditions. These steps of crude cellulose carboxymethylation displayed increased yield of DS molecular weight, CMC and hydrophilicity in water [66]. Recently, CMC was prepared from office waste materials such as papers to create an eco- friendly, inexpensive suppressant [67]. Joshi et al. discussed the possibility of CMC production from mixed office waste products [68]. Therefore, a lot of waste papers collected from different workplaces can be used as starting material for CMC production.
The alkylation-etherification process is the traditional approach for CMC synthesis. This process has been used in all research projects pertaining to CMC synthesis by applying different variation in chemicals ratios and reaction parameters (time, pH) from the very beginning. In addition to the cellulosic percentiles, the majority of precursors consist of a significant quantity of ash, lignin, pectin and minerals including Ca, K and P. Different pre-carboxymethylation steps are occasionally performed, including proteolysis, deactivation of different enzymes [69], lignin degradation [70], bleaching [69], acidic treatment and mixing with methanol, chloroform [58, 63], for isolating A-cellulose from natural origins. Pure A-cellulose is carboxymethylated and is carried out in two stages. In the first stage, cellulosic extracts are combined with NaOH for a specific duration. During this process, hydroxyl functional groups from each unit are replaced by –ONa groups selected for replacement by carboxymethyl groups in esterification step (Scheme 1, reaction (i)). For better penetration of reagents into structure of cellulose, inert solvents are added as swelling agent and diluent during this step.
In the next step, i.e., etherification, NaMCA is mostly functioning as an etherification agent [60, 67, 68, 72, 75]. In various studies, the process was modified by using different reagents, i.e., diazomethane [76], in place of traditional agent for etherification. The mercerized cellulose was mixed thoroughly with reagent at an optimized temperature and at specific time for getting best outcomes. The reaction is represented as (ii).
Following these two steps, CMC was prepared in form of solid suspension. Then, for obtaining the pure product without any impurities, the process of centrifugation and filtration was performed on suspension [68, 69, 75–79]. A flowchart illustrating the entire process of CMC synthesis from multiple precursors is shown in Figure 3.
Schematic description of CMC production from different precursors [80].
Due to their unique properties, CMC based composites have many applications in mitigating the pollution of wastewater. It can remove and degrade toxic dye contaminants [81]. There are many sources including industrialization from which many harmful and poisonous compounds are produced and released into water resources, leading to water pollution. Despite using different methods for removing pollutants, the residues left behind can be noxious and non-biodegradable [80, 82–85].
Jiao et al. synthesized a biopolymer-based flocculant from starch, acrylic acid and CMC for remediation of MB via graft polymerization. The results revealed maximum decolorization of MB (81.3%). It costs a quarter as much to operate as industrial anionic polyacrylamide. Because of its cheap operating costs, high efficacy, and environmentally friendly raw materials, this flocculant shows promise for treating industrial dye effluent [86]. An eco-friendly and inexpensive anionic terpolymer CMC based composite was synthesized via copolymerization assisted with microwave for removal of crystal violet. It demonstrated outstanding flocculation effects across a range of inorganic salts [87]. In another study, the hybrid of CMC and starch having undergone cationization through a reaction using Quat 188 in presence of a catalyst was produced. The cationized products and their corresponding parent materials were applied to textile scaling. According to outcomes, it was suitable for use as superior flocculating agent [88]. Further, a novel copolymer was synthesized by using CMC, N-vinyl formamide and acrylonitrile as starting materials. It has replaced the conventional polyacrylamide flocculant due to its excellent flocculation behavior and superiority [89]. A novel bio-based hydrogel comprising CMC and PAM was synthesized in a study for remediation of polluted water. It exhibited multiple ion adsorbent property and strong single-ion attraction toward lead, copper and cadmium ions. From adsorbed copper ions, copper nanoparticles were synthesized which illustrate its recycling application for metal ions. It also exhibited dual properties for treating wastewater and catalytic use [90]. The nanocomposite membranes synthesized from CMC and silica gel (as shown in Scheme 2), was used as a high performance adsorbent for metal and dyes decolorization from water [91].
Synthesis of CMC-graft-poly (acrylic acid) bentonite membrane [91].
Guan et al. synthesized an anionic copolymer from CMC, acrylamide and lignosulfonate. The ideal polymerization procedure was determined to be a 1:1:1 raw material ratio. In the broad range of various factors like pH level and salinity, it displayed exceptional color reduction ratios and rapid flocculation property. It also offers a practical approach for the efficient use of resources from biomass [92]. An efficient CMC-graphene oxide bio- based hydrogel composites was prepared for MB adsorption from industrial wastewater. A number of factors influencing the removal of MB dye were examined under various settings using batch tests [93]. Table 1 reprsents various CMC based composites that have been explored for wastewater treatment.
Sr No. | Types of CMC modification | Category of scaffold | Synthesis techniques | Application |
---|---|---|---|---|
1 | Starch blended with CMC and acrylic acid mixture | Copolymer | Graft polymerization | Removal of methylene blue [86] |
2 | Grafting of CMC and alginate by itaconic acid | Flocculant | Microwave-assisted copolymerization | In wastewater [87] |
3 | Amphoteric composite of CMC and DMC | Flocculant | Hydrothermal polymerization | Dewatering of sludge [94] |
4 | Starch and CMC based hybrids | Flocculant | Starch react with Quat 188 in various conditions | In wastewater [88] |
5 | CMC grafted with polyamidine | Flocculant | Graft polymerization | Coalmine wastewater treatment [89] |
6 | CMC and polyacrylamide based composite | Hydrogel | Free radical polymerization | Heavy metal ions removal [90] |
7 | CMC and poly (acrylic acid) with silica gel | Membrane nanocomposite | Graft polymerization | Removal of metals and cationic dyes [91] |
8 | Lignosulfonate and CMC blend with acrylamide | Flocculant | Graft polymerization | For removal of dye [92] |
9 | Graphene oxide with CMC | Hydrogel | Hummers method | Removal of methylene blue [93] |
CMC based composites for wastewater treatment.
Poly (acrylic acid) or PAA is a water-soluble molecule with a high molecular weight that is produced by polymerizing the monomer acrylic acid. The polmerization of acrylic acid is shown in Figure 4. It has almost all of the characteristics of a useful pharmaceutical polymer, including biodegradability, nontoxicity, and biological compatibility [95]. It is seen as a form of cross-linked network.
Polymerization of Poly (acrylic acid).
PAA is useful in the formation of polymeric compounds and nanocomposites. The different application of PAA has been described in Figure 5 [96]. It can create fragile, translucent films and has a glass transition temperature greater than 100 °C. This hygroscopic polymer can draw in and retain water molecules by absorbing or adsorbing them from the environment. Because of proton loss, PAA is an anionic polymer in water [97]. The cross-linking of PAA can be carried out by using radiation and chemical (allyl ethers of hydrocarbons) methods. Cross-linking of PAA is also possible at temperatures higher than 200 °C. High temperatures have the potential to cause PAA to lose water and create an insoluble network that is cross-linked [98].
Application of acrylic acid [96].
A substantial number of studies has been focused on incorporating or grafting PAA onto CMC to increase its ability to absorb metal ions [91, 99].
PAA based composites are highly effective materials for wastewater treatment. In a study, the magnetic nanoparticles incorporated into PAA hydrogel without using chemical or heat via diffusion assisted methods for fast adsorption of ammonium from sewage [100].
The development of a new hydrogel in the form semi-interpenetrating network by using PVA as a linear polymer during the process of copolymerization of acrylamide and acrylic acid. Hydrogels with varying molar ratios were tested for their capacity to adsorb MB. A weighed amount of dried hybrid hydrogel was stored at 37 °C after being submerged in a 50 ppm MB solution [101].
Ha et al. synthesized nanocomposite based on PAA and reduced graphene oxide (rGO) via thermal cross-linking. For obtaining rGO, HI vapors were employed onto the nanocomposites. The outcomes depicted high adsorption capacity of oil per g of material [96].
In order to simultaneously eliminate emulsion, dyes and metals, a modified composite with non-swelling property was synthesized from PAA and silica dioxide. It occurs in a linear form instead of having a network structure composites [102]. A copolymer was synthesized from grafting of acrylic acid onto the chitosan backbone by using method of free radical polymerization for dye removal from wastewater. It showed great promise as a flocculant due to its great performance, affordability, and environmental friendliness [103]. Table 2 summarizes PAA-based composites utilized in wastewater treatment.
Base components of poly (acrylic acid) based composites | Scaffold | Uses |
---|---|---|
Acrylic acid and monomethyl ethyl hydroquinone | Hydrogel | Ammonium adsorption from sewage [100] |
Acrylamide and acrylic acid | Hydrogel | MB removal [101] |
Silica dioxide NPs and PAA | Hydrogel | Removal of cationic dyes, heavy metals and surfactant emulsion [102] |
Starch, acrylic acid and chitosan | Flocculant | Dye removal [103] |
PAA and Fe3O4 nanoparticles | Nanocomposite | Arsenic/toxic ion removal (64,65) [104] |
Different poly (acrylic acid), PAA based composites for wastewater treatment.
There are different composites of CMC and acrylic acid synthesized for different applications. The synthesis of superabsorbent polymer (SAPs) was carried out by copolymerization of acrylic acid and CMC at room temperature using gamma radiation. The study systematically assessed the concentration of acrylic acid and the radiation dosage influence on hydrogels’ structural and functional features. The results displayed better water retention and growth of plants, highlighting their remarkable application in agricultural sector [105]. In another study, CCAC hydrogel composites synthesized from CMC and PAA infused with attapulgite. It showed capability of capturing heavy metal from aqueous solution and is used as an effective adsorbent [106]. These composites also have wide range of applications in removing different kinds of toxic dyes from wastewater water such as a novel adsorbent prepared by Zhang et al. by grafting of acrylic acid on CMC. The results revealed its excellent efficacy for removing dyes with good ratios; 79.6% for DP, 84.2% for MO and 99.9% for MG, making it a versatile adsorbent [85].
The adsorption of pollutants by CMC-PAA composites is governed by key molecular interactions like van der Waals forces, electrostatic forces, chelation and hydrogen bonding. These interactions are also governed by structural properties of pollutants and the functional groups within the composite.
CMC-PAA composites contain carboxyl (–COOH) and hydroxyl (–OH) groups that ionize in aqueous solution, acquiring negatively charged sites which attract cationic pollutants like Pb2+, Cd2+ and Cu2+ via electrostatic interactions. Hydrogen bonding exist between –OH groups of CMC and the polar functional groups of organic dyes like dyes and phenol, facilitating effective removal of contaminates. For example, CMC-g-PAA carbon dots nanocomposite captures MG dye via multiple adsorption mechanisms. The presence of amino groups, hydroxyl and amino groups in nanocomposite investigated by FTIR analysis, facilitate its ionic interaction with MG. MG dye is adsorbed into porous structure of nanocomposite, while 𝜋–𝜋 stacking with aromatic rings and hydrogen bonding reinforce its molecules binding. These combined mechanisms ensure removal of the dye.
For heavy metal remediation, carboxyl group of PAA provides strong chelation bonding with metal ions, forming stable complex. For example, the primary mechanism by which Cu (II) ions adsorb onto CMC-g-PAA is chelation with carboxyl group. FTIR analysis reveals a shift in the O–C–O vibration from 1625 cm−1 to 1603 cm−1 indicating the carboxyl groups’ role in Cu (II) binding. The bidentate coordination of these groups enhances the metal ion adsorption capacity of composite [107]. In another example, the molecular interaction in CMC/AAC hydrogel composite takes place by hydrogen bonding, ionic interaction and chemical grafting of functional groups, electrostatic attraction, and hydrogen bonding, the main mechanisms regulating molecular interactions in the CMC/AAc hydrogel. The hydrogel’s structural integrity and swelling behavior are improved by the substantial hydrogen bonding made possible by the presence of hydroxyl (–OH) and carboxyl (–COOH) groups [105].
Adsorption kinetic models are frequently used to study the adsorption processes. There are two models that are most widely used to assess the adsorption process of dyes. In the pseudo- first-order model, diffusion-controlled adsorption is described.
Pseudo first order:
The pseudo-second-order model describes chemisorption, where chemical interactions between the adsorbent and adsorbate determines the rate-limiting step.
Pseudo second-order:
MB adsorption kinetics on nanocomposite and its hydrogel of clay based carboxymethyl cellulose-acrylic acid (CMC-cl-PAA) were evaluated using pseudo-first-order and pseudo-second-order kinetic models. The adsorption capability of CMC-cl-PAA hydrogel reached equilibrium in 25 min, demonstrating a faster adsorption rate than the nanocomposite. The pseudo-second-order model offered the greatest fit, indicating that chemisorption interactions controlled the adsorption process, according to the correlation coefficient (R2 = 0.999) and RMSE values. This suggests that the rate-limiting step is the surface adsorption process [108].
Adsorption isotherms illustrate relationships between pollutants in solution and its interactions on composite surface. Their parameters provide information about properties of surface and adsorption mechanism. Three isotherm models were employed to assess the adsorption equilibrium. The Langmuir model assumes that adsorption occurs as a monolayer on a uniform surface. Langmuir isotherm model is depicted as follows:
Freundlich isotherm considers that the adsorption occur in multiple layers on an irregular surface. Freundlich isotherm model is expressed as:
Temkin isotherm is depicted as:
In a study of CMC and acrylic acid (CMC-AA) based adsorbent, the Langmuir, Freundlich, and Temkin isotherms were used to evaluate adsorption behavior. The Temkin isotherm was better for studying the adsorption behavior of DB and MG dyes than the other isotherms. Additionally, the presence of numerous interaction mechanisms between the CMC-AA adsorbent and MO dye is represented by the high R2 values for the Freundlich and Temkin models in MO adsorption [85].
Although CMC-PAA composites are known for their environmentally friendly features in wastewater treatment, a comprehensive assessment of their environmental impact across their lifecycle is crucial to evaluate their overall sustainability.
CMC, sourced from plant-based cellulose, is a renewable and environmental friendly polymer, making it a sustainable solution for wastewater treatment. It naturally degrades, reducing environmental treatment, while its water solubility and chemical modifications enhance its adsorption application [109]. The synthesis of CMC needs chemical modification; green synthesis approaches have been developed to mitigate waste generation and environmental harm [110]. PAA, though petroleum-derived, its inclusion in CMC-PAA composites is beneficial due to its remarkable chelating ability, which contribute to the composite’s performance in wastewater purification [111, 112]. There are ongoing efforts to decrease the environmental footprint of PAA production [113]. Thus, overall lifecycle effect CMC-PAA composites is lower than many traditional adsorbents due to the renewable nature of CMC and low amounts of PAA required. Moreover, CMC-PAA composites are manufactured with lower energy inputs than the synthesis of other adsorbents like activated carbon and synthetic zeolites [114–118].
CMC undergoes degradation in both terrestrial and aquatic environment and produced non- toxic byproducts through microbial action [80]. This makes it ecological friendly. PAA is less biodegradable compared to CMC; but incorporating CMC into composite boosts the biodegradation process, thus mitigating its long term environmental impacts [85]. Researchers are actively progressing on developing biodegradable substitutes for PAA including poly (lactic acid), to be used in comparable composite materials [119]. The biodegradability of CMC-PAA composites is superior to many synthetic adsorbents, and additional enhancements can be made by refining the composite’s composition and finding biodegradable alternatives to PAA.
CMC is safe and non-toxic for used in different applications, with green chemistry techniques minimizing the residual reagents from its synthesis [110]. PAA degradation products, like acrylate monomers, pose toxicity risks at higher concentrations, but the limited use of PAA in CMC-PAA composites significantly lower this risk [120]. The proper disposal and treatment of composites used further reduce the potential toxicity associated with their degradation.
CMC-PAA composites are highly efficient in eliminating heavy metals, dyes, and pollutants from wastewater, lowering the environmental impact of polluted water [85, 99]. While PAA- based materials have environmental persistence, the biodegradable properties of CMC ensures that the composite accumulates less than the completely synthetic adsorbents [121]. Research is being conducted to develop entirely biodegradable composites that retain the performance of CMC-PAA. Overall, the long-term environmental impact of CMC-PAA composites is manageable and their use in wastewater treatment helps to mitigate the pollution.
Characterization techniques mainly depend on the analysis of CCAC. Determining the morphology and other characteristic features of the synthesized composites is essential for describing their structural and functional properties, which in turn inform their potential applications. The Figure 6 illustrates the primary chracterization techniques including SEM, FTIR, and XRD.
FTIR spectra was employed to recognize the different moieties in reaction and spectral analysis of CMC and CMC-g-PAA composites. The chemical structure of CMC is characterized by a broad band near 3405 cm−1, attributed to the presence of hydroxyl (–OH) groups, and a distinct peak at 1629 cm−1, corresponding to carboxylate groups. Analysis of FTIR spectra of composite hydrogel showed peaks at 1697.24 cm−1, 671.18 cm−1 and 918.05 cm−1 indicating the existence of COO–, C–O and C–O–C respectively [122]. In another study, synthesis of copolymer hydrogels based on CMC and acrylic acid was confirmed by the appearance of band at 1529.55 cm−1 [105]. The surface features of composites were studied by using AFM analysis. In carbon dots (CD) based NaCMC-g-PAA hydrogels, the polymer hydrogels matrix were entangled with hydrogels particles shown by AFM studies. The morphological studies of adsorbents indicated their porous, heterogeneous and amorphous nature [122].
SEM studies displayed the structural configuration of composites. CMC-AA adsorbent displayed their smooth surface with pores while pure CMC is featured by its rough structure [85]. TGA analysis was performed for determining the thermal stability of composites at different intervals of temperature. In a study of CMC; cPAA based composites, TG results showed an increase in maximal temperature values that describe promising interaction between polymer chains, indicating their greater stability at higher temperature [99]. XRD technique used for phase identification and for analysis of crystalline size of phases of composites. The synthesis of NACMC grafted by PAA containing CD was confirmed by XRD peaks without any extra peaks. Similarly, elemental analysis of CD obtained from EDS analysis [122].
Characterization techniques.
Composite materials based on CMC and PAA exhibit considerable efficiency for high water absorption, removing heavy metals and organic contaminants because of functional groups (such as carboxyl and hydroxyl groups), a large surface area, and adjustable porosity [123]. Activated carbon (AC) features a microporous structure, high internal surface area with functional groups that influence pH and optimize adsorption [124, 125]. Despite their effectiveness in removing organic contaminants (dyes, pesticides), AC is ineffective against inorganic pollutants due to absence of specific functional groups and also prone to bacterial growth, so require maintenance or replacement [125, 126]. Zeolites are also widely used as adsorbents due to their sustainability, affordability, and selective adsorption properties and releasing harmless ions like K+, Na+, Ca2+ and Mg2+ [127]. However, its ability to adsorb phosphorus and heavy metal oxyanions is relatively low. To address this, there is need to modify zeolite by various ways like acid or alkali treatment, metal oxide impregnation and surface functionalization. Therefore, they are less effective unless modified [128]. Biopolymers, or natural polymers, are substances that are generated by living organisms including plants, animals, bacteria during their life span [129]. Biopolymers are a sustainable alternative to synthetic reagents due to their adsorption efficiency by many functional groups [130]. Compared to CMC-PAA composite they have less adsorption capacities due to synergy between hydrophilic and biodegradable nature of CMC and PAA strong chelating ability [131, 132].
Raw materials of CMC-PAA based composites are also low-cost and broadly available. The synthesis process is simple and scalable, making these composites economical [133, 134]. AC is not cost effective because its extensive production process includes carbonization and activation at high temperature which are expensive. Furthermore, it requires high energy input and advanced equipment, adding to cost and hindering its widespread adoption in wastewater treatment [114–116]. Natural zeolites are significantly cheaper due to their natural abundance and ease of extraction. Their price is generally 80–90% lower than synthetic zeolites. In contrast, cost of synthetic variants are expensive due to their intricate production process which require energy consumption [117, 118]. Biopolymers like chitosan are cost-effective due to their natural abundance [135] however, their stability requires modification and cross-linking which drive up their production costs [136].
These composites originate from renewable sources, as CMC is a cellulose based material, and they are biodegradable in nature. Their synthesis is sustainable, generating minimal harmful byproducts [109, 137]. In contrast, the production of activated carbon from shells or wood involves high temperature carbonation, resulting in substantial energy use. Additionally the disposal of used AC raise environmental issues [138]. Natural zeolites are considered ecofriendly due to their natural abundance and simple extraction processes that require minimal energy [139]. Synthetic zeolites are used in various application such as catalysis and ion exchange consume significant energy and resources [140]. Biopolymers such as chitosan are known for their biodegradability and ecofriendly nature. However their modification process in order to enhance their properties often use chemical reagents which may pose environmental risks [141].
CCAC have gained significant attention due to its versatile applications in various fields. In wastewater treatment, they serve as effective adsorbent for various dyes and heavy metals as discussed below:
The synthesis of superabsorbent polymer (SAPs) was carried out by copolymerization of acrylic acid and CMC at room temperature using gamma radiation. The study systematically assessed the concentration of acrylic acid and the radiation dosage influence on hydrogels’ structural and functional characteristics. FTIR spectroscopy was used for structural analysis, gel content evaluations, and swelling capacity assessments as part of the characterization process. The hydrogels’ biodegradability and capacity to improve water retention in soil and sand were also investigated. In order to assess their application in agriculture, studies were conducted to see how they affected the growth of immature plants and the germination of lady finger and wheat seeds. The results demonstrated significant improvements in water retention and growth of plant, highlighting their potential in agricultural applications [105].
The hydrogel composites of CMC-g-PAA/attapulgite were synthesized and assessed for their efficacy in removing Pb (II) ions from aqueous medium. The adsorption studies were carried out by adjusting by pH, ionic strength, lead ion concentration, contact time and attapulgite content. According to kinetic studies, equilibrium was attained in 60 min, indicating that the adsorption process proceeded rapidly. Within the first 10 min for composites with 5 wt.% attapulgite (APT) and within 30 min for those with 20 APT, more than wt.% 90% of the equilibrium adsorption occurred. The schematic description of CMC-g-PAA/APT is shown in Figure 7. According to FTIR analysis, complexation was important to the adsorption process. Overall, the newly synthesized hydrogel composites showed considerable promise as effective and economical adsorbents [106].
Schematic description of CMC-G-PAA/APT composites for Pd (II) adsorption mechanism.
CMC-g-PAA was synthesized through the homogenous graft copolymerization of methacrylate carboxymethyl cellulose along with the acrylic acid. The addition of carboxyl groups to the long-chain PAA greatly increased the material’s ability for absorbing copper ions. FTIR spectroscopy and SEM were used to characterize the resultant copolymer. According to the Langmuir model, the highest adsorption was 154.32 mg/g, which displayed considerable increase in the efficient sequestration of copper ions when compared with unmodified CMC. Contact time, starting copper ion concentration, and pH were among the key parameters that were examined along with the removal of Cu (II) ions from aqueous solutions. Kinetic studies and isothermal adsorption equilibrium highlighted the excellent adsorption performance of composite. In addition to addressing environmental problems, using cellulose generated from plants material for adsorbent generation offers an affordable way to extract heavy metal content from waste effluent. This study highlights the potential of CMC-g-PAA as a viable and sustainable adsorptive material for water purification [107].
A novel cellulose-based adsorbent, CMC-AA, was manufactured via grafting acrylic acid onto CMC. Under optimum synthesis conditions, the grafting efficiency was 85.6%. The adsorbent showed excellent removal efficacy for dyes, with removal ratios of 79.6% for Disperse Blue 2BLN (DB), 84.2% for Methyl Orange (MO) and 99.9% for Malachite Green chloride (MG). FTIR and SEM confirmed the synthesis of a new adsorbent under the specified conditions. Chemical adsorption was indicated by kinetic analysis, which revealed that the adsorption followed a pseudo-second-order model. The equilibrium data was best fitted by the Temkin isotherm, which indicates that CMC-AA functions via a chemical adsorption process, making it a highly versatile and effective dye removal adsorbent [85].
The hydrogels with IPN polymer network were synthesized by combining CMC solution with cross-linked PAA in different mass ratios, followed by crosslinking of CMC chains using citric acid to form full IPN structures. The CMC:cPAA hydrogels were subjected to freeze-drying to examine their density, swelling tedency, compressive elasticity, and heat tolerance. The adsorption efficacy of the CMC:cPAA hydrogels was assessed by using MB dye at pH value of 7 and Cu2+ ions at 4.5. Adsorption data were carried out by Langmuir, Freundlich, and Dubinin–Radushkevitch models, indicating that the 50:50 CMC: cPAA hydrogels exhibited the highest adsorption capacities: 613 mg/g for MB dye and 250 mg/g for Cu2+ ions. These results demonstrate the potential of CMC:cPAA hydrogels for effective pollutant removal, with excellent recyclability posing significant cost-effective benefits [99].
CMC/acrylic acid hydrogels nanocomposite with magnetic clay as adsorbent for MB were synthesized by free radical polymerization method. The samples were investigated by using different spectroscopic techniques. The capability of adsorption was studied in batch mode. The nature and behavior of adsorption process was evaluated by experimental data collected from adsorption kinetics and isotherm models. It can be inferred from the adsorption thermodynamic studies that the adsorption process was spontaneous and endothermic in nature. This chemical modification resulted in maximum adsorption efficacy, excellent regeneration stability, good thermal stability and mechanical strength. This study showed the potential of novel hydrogel nanocomposites as a high performance adsorbent in eliminating the organic dyes from aqueous medium [108].
In order to eliminate MG dye from aqueous solutions, this study aimed to develop a novel hydrogel nanocomposite sodium CMC-g-PAA incorporated with carbon dots. The functional groups, morphology, particle size, and crystallographic characteristics of the nanocomposite were thoroughly characterized both before and after dye adsorption. The findings demonstrated the occurrence of several ionic functional groups, including carboxyl, amino, and hydroxyl groups, which support the adsorptive properties of the nanocomposite. According to morphological analysis, it was porous, heterogeneous, and amorphous, all of which improve the adsorption of malachite green dye. Carbon and oxygen were identified as the material’s main constituents by elemental analysis. The ideal conditions for attaining a 96.92% MG dye removal efficiency were found to be 30 °C, 0.06 g of nanocomposite dosage, and a pH of 10 for the solution. The complex dynamics of the adsorption process were revealed by kinetic and isothermal modeling, and the pseudo-second-order and Freundlich models were found to be the most suitable for describing the system. The adsorption process was endothermic and spontaneous, according to thermodynamic analysis. The outcomes demonstrated the property of nanocomposites in successful capturing of MG dye from water [122]. Table 3 highlights CMC-AA based composites employed as adsorbents in wastewater treatment.
Synthesis method of composites | Target pollutant | Adsorption capacity | References |
---|---|---|---|
Grafting polymerization | Dyes | Methyl orange: 84%, Dispersal blue: 79.6%, Malachite green: 99.9% | [85] |
Solution casting method | Methylene blue dye, Cu2+ ions | 613 mg g−1 , 250 mg g−1 | [99] |
Free radical polymerization method | Methylene blue dye | 1109.55 mg/g, 1081.60 mg/g | [108] |
Free radical copolymerization | Malachite green | 96.92% | [122] |
Carboxymethyl cellulose-acrylic acid based composites as adsorbent.
The sodium CMC-g-PAA hydrogel was manufactured at CMC, AAm, and AAc. The initiator and the cross-linking agent were potassium persulfate (KPS) and N, N-methylene bisacrylamide (N-MBA), respectively. FTIR, XRD, FESEM, and TGA studies characterized the newly synthesized hydrogel. Its efficacy in removing metformin hydrochloride (MH) from aqueous solutions was also evaluated. The study looked at how different characteristics, such as pH (1.2–12), temperature (15, 20, 25, and 30 °C), equilibrium time (1–240 min), and adsorbate concentration (0.001–0.1 g), affected adsorption effectiveness. The results revealed that when temperature and pH increased, the adsorption performance decreased. The optimum equilibrium time was found to be 120 min. The adsorption of MH on the hydrogel was found to be more effectively described by the Freundlich and Temkin isotherm equations model than by the Langmuir model. The MH adsorption mechanism was spontaneous and exothermic [142].
In this study, the thermos responsive composite hydrogel was synthesized from N- isopropylacrylamide and acrylic acid while using CMC as the crosslinking agent. Orthogonal experiments were employed for optimizing the conditions of synthesis. FTIR spectroscopy was used to determine the hydrogel’s chemical structure, while scanning electron microscopy (SEM) demonstrated its porosity microstructure. In order to remove U (VI) from synthetic wastewater, the hydrogel’s adsorption performance was assessed. The adsorption equilibrium was attained in 1 h. At pH 6, a temperature of 298 K, an initial U (VI) concentration of 5 mg⋅L−1, and 10 mg of hydrogel, the maximum adsorption capacity attained was 14.69 mg⋅g−1. While the adsorption isotherms fitted the Langmuir model, kinetic investigations revealed that the adsorption followed a pseudo-second-order model. The acylamino group’s significant role in uranium adsorption has been confirmed by chemical investigation. After 5 alternating adsorption–desorption cycles at 20 °C and 50 °C, desorption and reusability tests indicated a retention rate of roughly 77.74%. XPS study showed complexation between oxygen-containing functional groups and U (VI) as the major mechanism for UO sorption. These results imply that the heat sensitive CMC/P(NIPAM-co-AA) hydrogel has potential as an innovative adsorption medium for the effective extraction of U (VI) from wastewater with small concentrations of uranium [143].
A nanocomposite polymer was synthesized from copolymerization of CMC, starch and acrylic acid incorporated with Al2O3 as filler by employing gamma radiation at specific dose for removing Nd(III) through batch sorption process. Further, it was found that Freundlich model and sorption process were in agreement with each other. The nanocomposites were investigated by different techniques and optimal conditions were revealed by studying various parameters. All results underscore the potential of nanocomposites for efficient and selective separation of Nd (III) [144].
In another study, hydrogel composite as an adsorbent was synthesized by grafting of AA and itaconic acid on CMC using potassium persulfate as initiator for the isolation of safranin-O from wastewater treatment. The composite incorporated with nano-sheets of montmorillonite clay showed better swelling and removal efficacies. The optimizing conditions for composite investigated via RSM-CCD method by using various parameters such as dose of adsorbent, pH and time of contact. Different kinetics, thermodynamics and isotherm studies was done for investigating the adsorption process. The maximum adsorption property was 19.12 mg/g [145]. Table 4 outlines CMC–PAA derivatives and their applications in wastewater treatment.
Composite derivatives | Applications | References |
---|---|---|
CMC-acrylic acid copolymerized with acrylamide | Metformin hydrochloride removal from aqueous solution | [142] |
CMC and acrylic acid copolymerized with itaconic acid | Dye removal from textile water | [145] |
CMC-starch grafted acrylic acid composite with Al2O3 | Capturing of Nd (III) from mixture of Nd (III)/Co(II) | [144] |
CMC with poly(N-isopropylacrylamide) copolymerized with AA | Capturing of U (VI) | [143] |
CMC-PAA derivatives and their application.
The large-scale synthesis of CMC-PAA composites involves evaluating material costs, synthesis expenses, and operational factors. CMC, a cost effective and renewable material obtained from cellulose, ia abundant and contributes to the composite’s economic viability [146].
PAA, an inexpensive commercial polymer, is commonly produced by polymerization of acrylic acid [147]. However, its production cost as a petroleum derived polymer, may be affected by changes in crude oil prices, which impact the overall cost of production [96]. Nevertheless, inclusion of CMC in the composite decreases dependency on synthetic polymers providing a more economical alternative. Furthermore, the superior adsorption efficacy of CMC-PAA composites minimizes the quantity of material needed for wastewater treatment, significantly reducing operational costs.
Beyond their economic benefits, the industrialization of CMC-PAA composites depends on efficient synthesis methods that ensure material performance while reducing waste and energy requirements. Synthesis methods used at the laboratory scale, including cross-linking approaches and free radical polymerization require optimization and must be scaled up for industrial manufacturing [105, 106]. The adoption of commercial reactors and continuous production techniques can support large-scale synthesis, while ensuring uniformity in material properties. Moreover, by employing green synthesis methods microwave-assisted and solvent-free approaches can significantly enhance scalability while ensuring a reduced environmental sustainability [107, 148].
Several challenges including ensuring consistent performance, environmental regulations and integrating with current infrastructure must be tackled to effectively use CMC-PAA composites in industrial wastewater treatment. These include:
For industrial applications material must show consistency in adsorption efficiency and mechanical strength [149, 150]. The performance of the composite may be influenced by differences in raw materials such as CMC extracted from diverse plant origin [151].
Environmental regulation must be followed to prevent adverse ecological effects, in the manufacturing and disposal of PAA containing materials [152]. The development of biodegradable alternatives, like poly (lactic acid)-based composites, may contribute to long term sustainability.
Industrial wastewater treatment rely on well-established adsorption and filtration technologies. Therefore, in order to facilitate smooth implementation, the compatibility of CMC-PAA composites with existing system like packed bed reactors and membrane filtration units, must be examined [106, 153].
Although CMC-PAA composites reveal high adsorption capabilities, their industrial application require regeneration and reuse strategies. Investigating chemical and thermal techniques of desorption can help maximize to extend their operational lifespan [148].
The reusability, practical applicability and long term stability of composites play an important role during the adsorption process. Effective regeneration approaches maintain adsorption performance while improving cost-efficacy and environmental impacts. Different regeneration techniques have been explored in order to restore adsorption capacity after multiple cycles. Few studies show significant regeneration efficiency across several cycles.
The effectiveness, stability and reusability of hydrogel nanocomposites of CMC-cl-pAA and magnetic CMC-cl-pAA were evaluated over four adsorption–desorption cycles. Both nanocomposites showed good stability. However, the magnetic CMC-cl-pAA demonstrated improved stability without an apparent reduction in performance. It may use magnetic field to remove MB dye. The effectiveness and dependability of the adsorption process were demonstrated by UV-Vis spectroscopy, which verified the successful removal of the dye because the absorbance intensity of MB dramatically dropped without change in wavelength [108].
In another example, for the adsorption studies, a mixed metal ion solution (Cu2+, Pb2+, and Cd2+, each at 100 mg/L) was carried out at a specific pH and a dry hydrogel composite was submerged and shaken for 24 h [154]. CMC-based composite hydrogel, after desorption of metal was submerged in EDTA solution, followed by multiple washes with deionized water. The regenerated hydrogel was reused for further adsorption cycles. The results showed that, even after three cycles, it maintained high adsorption capacity with minimum decline, demonstrating its excellent regeneration potential for practical applications [90].
In general, CMC-PAA composites show encouraging regeneration potential; however, additional studies are required to optimize settings that reduce degradation while preserving high adsorption efficiency over long cycles.
Currently, the application of CMC/PAA composites is restricted to laboratory studies, with no reported real-world example as well as pilot scale implementation of CMC/PAA composites. Studies have predominantly focused on optimizing their adsorption efficiency and stability under controlled experimental setup. However, additional research is needed to assess their viability for large scale industrial and ecological implementation.
This review highlights the synthesis, properties and applications of various innovative CMC and Poly (acrylic acid) based composite material, emphasizing their effectiveness in wastewater treatment. These composites efficiently address the environmental challenges due to their chemical functionality and adsorption properties. Despite the remarkable performance of individual components, their composites enhanced performance through synergistic interactions. Integrating advanced technologies particularly nanomaterials, such as graphene oxide and metal nanoparticles, expand their potential as high-performance adsorbents. Furthermore, innovative synthesis methods should be investigated to enhance the environmental sustainability of these materials. The implementation of green strategies, such as bio-based cross-linker and solvent-free fabrication will further enhance the effectiveness and biodegradability of these composites. Future studies should concentrate on crucial areas to maximize the potential of CMC-based composites in wastewater treatment. The manufacture of multifunctional composites that improve mechanical stability, selectivity, and adsorption efficiency is an important approach. Other critical research priorities for these composites include a comprehensive assessment of their long term performance and regenerative kinetics. Quantitative research must characterize the evolution of material properties across successive adsorption–desorption cycles. In addition, a thorough techno-economic evaluation of scale-up parameters is necessary to set operational limits and optimize regeneration procedures for continuous-flow wastewater treatment systems. By addressing these research gaps, this field can evolve towards the synthesis of next-generation CMC based composites that are not only effective at removing pollutants but also ecologically friendly and commercially viable. Overall, CMC and PAA based composites provide a promising solution for effluent remediation. Their eco-friendly nature, coupled with multifunctionality, make them good candidates for large-scale application in water reclamation. Even though, advancing these materials towards industrial implementation remain a crucial area for future exploration and open a new avenue for researchers to purify the wastewater by using these composites.
The authors would like to thank the management of the Center for Environment Protection Studies, Council of Scientific and Industrial Research, Ferozepur Road Lahore, 54600, Pakistan, for their cooperation in the successful completion of this research.
Idrees, Shazmeen: Conceptualization, Methodology, Investigation, Data curation, Writing Original Draft; Dr. Abbas, Naeem: Supervision, Validation, Formal analysis, Writing Review & Editing; Dr. Asghar, Amina: Visualization, Resources; Hammad Khan, Muhammad: Project administration; Hussain, Naqi: Writing review & editing, Visualization.
This research did not receive external funding from any agencies
Not Applicable.
Source data is not available for this article.
The authors declare no conflict of interest.
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Article Type: Review Paper
Date of acceptance: May 2025
Date of publication: July 2025
DOI: 10.5772/geet.20250012
Copyright: The Author(s), Licensee IntechOpen, License: CC BY 4.0
© The Author(s) 2025. Licensee IntechOpen. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
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