Statistically optimised sequestration of mefenamic acid from polluted water by acacia gum phthalate/pectin hydrogel: A novel multifunctional adsorbent material synthesised via microwave-assisted process

Abstract

Pharmaceuticals and personal care products (PPCPs) are an emerging class of perilous pollutants due to their potential inimicalimpacts on ecosystems necessitating their abatement.Herein, an environmentally-affable and multifunctional acacia gum phthalate/ pectin hydrogel (AGP/PEC) was innovatively synthesised by microwave-assisted free-radical polymerisation for subsequent mefenamic acid (MFA) decontamination from synthetic wastewater. The physicochemical characteristics of AGP/PEC was studied through FTIR, XRD, BET, TEM, SEM-EDX and XPS characterisation techniques showing the existence of –OH and –COOH functionalities, rough surface with good surface area (18.95 m2/g) and porosity that contributed to high MFA uptake (93.45%) via hydrogen-bonding, electrostatic, pore-filling, π−π, and n−π interactions. The independent and interactive influences of operative variables on the adsorption capacity of AGP/PEC was statistically evaluated via central composite design of response surface methodology. The most-effective MFA uptake was attained at optimal operating conditions: initial solution pH (5.9), dosage (0.4 g/L), and time (28.5 min). Langmuir isotherm with Qm = 103.43 mg MFA/g and pseudo-second order kinetic models best-correlated the corresponding data. The Qm increased with temperature specifying an endothermic process, which was authenticated by positive ΔH⁰ (= 7.75 kJ/mol). The parameter, bT = 0.16 kJ/mol and ED = 2.12 kJ/mol, calculated from Temkin and Dubinin−Radushkevich isotherm models, respectively specified physisorption. The better adsorptive competence in real water along with an excellent reusable potential (87.1%) up to fifth cycle designated AGP/PEC as a potent adsorbent for practical purposes. These findings accentuated that AGP/PEC could be gainfully implemented as green and advanced multifunctional adsorbent material for removing residual MFA from wastewater.