Diclofenac removal in water supply by adsorption on composite low-cost material

This work objective was to evaluate batch adsorption processes using polyethylene terephthalate composite (PTC) material, sugarcane bagasse ash (SBA) functionalized with iron oxide (Fe³⁺) (PTCSBA/ Fe³⁺) in the adsorption of 1000 µg  L^-1 of diclofenac sodium (DIC) in synthetic solution, simulating water supply. The batch test was started by determining the adsorbent mass (0.1, 0.2, 0.3, 0.4 and 0.5 g) to remove 1000 µg L^-1 of DIC, followed by the adsorption kinetics and adsorption isotherm assays, evaluating the reaction rate and adsorption capacity, respectively. The PTCSBA/ Fe³⁺ mass that had the best efficiency in the DIC removal was 0.3 g, the pseudo second-order kinetic model (PSO) was the one that best fit the study having a determination coefficient (R²) equals to 0.97. The PTCSBA/ Fe³⁺ has good characteristics for DIC adsorption, achieving a 93% removal rate of sodium diclofenac. The composite is a low-cost adsorbent, 0.08 cents per kilogram of material, becoming a material with satisfactory characteristics for the removal of DIC. Therefore, it is recommended to use PTCSBA/ Fe³⁺ as adsorbent material in small water filter systems in order to remove DIC due to the low cost of the composite.