Valorization of viscose textile waste for the adsorptive removal of organophosphate pesticides from water

Abstract

This study investigates the potential of carbon materials derived from viscose textile waste as effective adsorbents for the removal of organophosphate pesticides, specifically malathion, chlorpyrifos, diazinon, phorate, and azinphos-methyl from water. Seven carbon materials were synthesized at varying carbonization temperatures using the same precursor, and their physicochemical properties were characterized through Scanning Electron Microscopy, Energy Dispersive X-ray Analysis, Fourier Transform Infrared spectroscopy, Brunauer-Emmett-Teller surface area analysis, Raman spectroscopy, and Zeta potential measurements. Screening tests identified the most efficient adsorbents for pesticide removal, followed by kinetic and equilibrium studies elucidating the adsorption mechanisms. The pseudo-second-order kinetics and Sips isotherm models best described the adsorption process. The highest adsorption capacities of the best-performing material follow the order: diazinon (76.1 mg g−1) > chlorpyrifos (32.0 mg g−1) > azinphos-methyl (24.3 mg g−1) > malathion (10.9 mg g−1) > phorate (0.4 mg g−1), suggesting that aromatic pesticides adsorb to a greater extent on the presented materials, compared to aliphatic ones. The analysis of the regeneration potential of the adsorbents revealed successful multiple adsorption-regeneration cycles with minimal performance loss when using 96 % ethanol as a regenerant. This research demonstrated the innovative use of viscose textile waste for sustainable adsorbents to address pesticide contamination in water, emphasizing the importance of optimizing adsorption and regeneration processes while utilizing renewable resources to tackle modern environmental challenges. Environmental implications: This study explores the potential of carbon materials derived from viscose textile waste for the adsorption of organophosphate pesticides, which pose significant risks to aquatic ecosystems due to their persistence and toxicity. Utilizing viscose textile waste contributes to effective water remediation and supports sustainable waste management by repurposing a discarded resource. Additionally, the carbonization process involved in producing biochar effectively sequesters carbon, helping to mitigate greenhouse gas emissions. The synthesis process includes a minimum of chemicals, reducing overall environmental impact. This approach promotes a circular economy by transforming waste into valuable materials for environmental protection and sustainably addressing contamination issues.