Preparation of polyethylene grafted cellulose for the removal of diethyl phthalate from wastewater

Abstract

A novel polyethylene glycol (PEG)-functionalized cellulose adsorbent (PEG-Cell) derived from sawdust was developed for the efficient removal of diethyl phthalate (DEP) from wastewater. The synthesis involved sequential acid (0.1 M HCl) and alkaline (0.1 M NaOH) hydrolysis of sawdust, followed by sodium chlorate bleaching and PEG grafting to introduce hydrophilic glycol groups onto the cellulose matrix. The PEG-Cell adsorbent demonstrated exceptional DEP removal performance at optimized conditions: initial DEP concentration (100 mg/L), adsorbent dose (0.6 g/L), contact time (60 min), and pH (7) achieving 97.5% removal efficiency and a remarkable adsorption capacity of 512.46 mg/g. Equilibrium studies revealed that the adsorption process followed the Langmuir isotherm model, suggesting monolayer coverage and strong chemical interactions between DEP molecules and PEG-Cell's functionalized surface. Kinetic study indicated that the adsorption adhered to the pseudo-second-order model, confirming chemisorption as the dominant mechanism. Thermodynamic investigations further supported the process's feasibility, with negative ΔG° values (-8.3 kJ/mol) indicating spontaneity, while positive ΔH° (45.3 kJ/mol) and ΔS° (0.18 kJ/mol·K) values suggested an endothermic and entropy-driven process. The adsorbent exhibited excellent reusability, maintaining high efficiency (>90%) over multiple regeneration cycles with minimal capacity loss. These findings highlight PEG-Cell as a cost-effective, sustainable, and highly efficient adsorbent for removing DEP and other phthalates from contaminated water sources, offering significant potential for scalable wastewater treatment applications.

Keywords: Emerging contaminants; Functionalized-cellulose; Phthalates removal; Surface functionalization; Water treatment.