Graphene’s incorporation into polymers has enabled the development of advanced polymer/graphene nanocomposites with superior properties. This study focuses on the use of a microcellular foamed polystyrene (PS)/graphene (GP) nanocomposite (3 wt%) for nickel (II) ion removal from aqueous solutions. Adsorption behavior was evaluated through FTIR, TEM, SEM, TGA, and XRD analyses. Key factors, including initial ion concentration, pH, temperature, and sorbent dosage, were examined. Results showed optimal nickel removal at specific pH levels with removal efficiency decreasing from 91 to 80% as Ni (II) concentrations increased from 10 to 100 mg/L. The adsorption capacity improved from 11 to 130 mg/g. Equilibrium data aligned with Langmuir and Freundlich isotherm models, while adsorption kinetics followed a second-order kinetic model. These findings highlight the potential of PS/GP nanocomposites for nickel ion removal, offering a promising solution for small-scale industrial applications.

Industries frequently discharge elevated levels of lead and cadmium into the environment, posing significant threats to ecological balance and public health. This study developed a novel polycaprolactone–chitosan–montmorillonite (PCL/CS/MMT) composite to adsorb Pb(II) and Cd(II) from aqueous solutions. The composite was synthesized via twin‐screw melt extrusion and subsequently characterized using X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), revealing a crystalline structure, cracked surface morphology, functionalized surface groups, and thermal stability. Under optimal batch conditions, the adsorbent achieved maximum adsorption capacities of 12.35 mg/g for Pb(II) and 16.92 mg/g for Cd(II). Adsorption behavior followed the Langmuir isotherm model, and kinetic data aligned with the pseudo second‐order model, indicating a chemisorption‐driven mechanism. The composite demonstrated effective regeneration, retaining over 55% adsorption efficiency after seven desorption cycles with 0.1 M (pH 8). These findings position the PCL/CS/MMT composite as a promising, sustainable adsorbent for wastewater treatment, offering a viable solution to heavy metal pollution and advancing the development of eco‐friendly materials for environmental remediation.

Climate change and water pollution are the global focus to address the mitigation measures that will improve water quality and wastewater management. The recent increase in dye pollution from the manufacturing sector, particularly the textile industries, has increased the demand for advanced wastewater treatment technologies that are sustainable and affordable. The abundant, renewable lignocellulosic fiber-based adsorbents have emerged as a promising alternative for removing a wide range of heavy metals and dyes. This review highlights in detail various sources of fibers, their physicochemical compositions, and different modification techniques that improve their selectivity and adsorption capacity, particularly for dye removal. The complementary impacts of the presence of the inherent functional groups, specific surface charges, and the primary adsorption mechanisms that can significantly enhance dye selectivity have been well addressed. While the modified fibers demonstrated the promising removal efficiency of above 90% at the laboratory scale, challenges remain in terms of their adsorption kinetics, regeneration efficiency, and long-term stability for large-scale industrial settings. Hence, future studies should focus on enhancing fiber properties for sustainable industrial applications, high-performance, and multifunctionality through a promising hybrid modification technique that will bridge the gap into large industrial implementation.

Microcellular injection-molded polypropylene/oyster shell nano-powder (PP/OSP) composites show potential as adsorbent materials for reducing toxic metal ion contamination in groundwater. This study investigates the material properties of PP/OSP composites and evaluates their Pb(II) adsorption performance in aqueous media. The effects of key operational parameters, including contact time, pH, and initial Pb(II) concentration, were examined to determine the optimal conditions for heavy metal remediation. The composites were characterized using XRD, SEM, FTIR, and TGA to assess their crystalline structure, surface morphology, functional groups, and thermal stability, respectively. Adsorption isotherm analysis indicated that the Pb(II) uptake behavior followed both the Freundlich and Temkin models. Kinetic studies showed that the adsorption process was best described by the pseudo-first-order model. The maximum adsorption capacity for Pb(II) removal was determined to be 13.89 mg/g.

Microcellular injection-molded oyster shell nano-powder (OSP) with polypropylene (PP) is a potential adsorbent material that can reduce toxic metal ion contamination in groundwater. This study aims to investigate the PP/OSP composite material properties and determine the toxic metal ion adsorption properties of polypropylene/oyster shell nano-powder (PP/OSP) in an aqueous medium. This research focused on lead Pb(II) ion using different parameters such as contact time, pH value, and initial concentrations to optimize the conditions for heavy metal remediation. Characterization techniques such as XRD, SEM, FTIR, and TGA were used to analyze the surface morphology, functional groups, and thermal stability, respectively. The adsorption isotherms were conducted, and the behavior was consistent with the Langmuir and Temkin isotherms. A pseudo-first-order kinetic model was preferred, with a maximum adsorption capacity for lead removal obtained at 13,89 mg/g.

Arsenic contamination in water bodies caused by acid mine drainage (AMD) and industrial effluents presents severe threats to public health and aquatic ecosystems. Although activated carbon (AC) is an effective adsorbent, conventional powdered AC suffers from severe operational limits, including filter clogging, high pressure drop, and secondary pollution. Encapsulating AC inside dense low-density polyethylene (LDPE) matrices resolves powder handling issues but severely restricts contaminant mass transport. In this study, novel lightweight LDPE/AC composite foams (1, 3, 6, and 10 wt% AC) were fabricated using microcellular injection molding with supercritical nitrogen (scN₂). The microcellular architecture thinned the polymer cell walls and generated an interconnected porous cell network, exposing embedded AC particles directly to the aqueous media. Morphological and thermal analyses confirmed uniform filler dispersion and preserved matrix stability, with the 10 wt% AC composite foam reaching a high BET surface area of 374 m²/g. Tensile modulus increased with AC loading up to 2535 MPa. Batch adsorption studies demonstrated optimal removal efficiency for As(III) at pH 7–8 and As(V) at pH 3, achieving maximum adsorption capacities of 20.71 mg/g and 24.00 mg/g, respectively. Treated water streams successfully met the WHO and South African SANS 241:2015 drinking water standard of 10 ppb. The adsorption dynamics obeyed pseudo-second-order kinetics and fitted the Freundlich isotherm model, indicating multi-layer chemisorption across heterogeneous surfaces. Desorption using 0.1 M EDTA retained high efficiency over 10 consecutive cycles. This work demonstrates microcellular LDPE/AC composite foams as a scalable, high-strength, and durable material platform for heavy metal remediation.