Hydrogen Sulfide Removal from Downstream Wastewater Using Calcium‑Coated Wood Sawdust‑Based Activated Carbon

摘要

Hydrogen sulfide is very toxic and dangerous. It can be observed in a huge amount in petroleum wastewater. In this study,residual wood sawdust was chemically modified by potassium hydroxide to produce wood sawdust activated carbon (ACWSD)and subsequently coated with calcium (Ca) extracted from eggshell. The Ca-coated ACWSD was applied in the sorptionof dissolved H_2S and its ions ( HS~− and S~(2−)) from simulated wastewater. Response surface methodology was employed toinvestigate the impact of various variables such as calcination temperature, concentration of calcium solution, and calcinationcontact time on the responses. The result showed that the highest adsorption capacity and product of impregnated activatedcarbon (IAC) were obtained at the following optimum conditions: calcination temperature of 890.86 ℃, calcium concentrationin the solution of 49 v%, and impregnated contact time of 61.58 min for the preparation of Ca-ACWSD, resulting in thehighest removal efficiency (RE%) and IAC yield % of 96.86% and 30.161%, respectively. X-ray powder diffraction, scanningelectron microscopy, and energy-dispersive X-ray spectroscopies were used to confirm the physicochemical propertiesof the Ca-ACWSD adsorbent. Modified activated carbon has higher RE % compared with unimpregnated one. Freundlichisotherm model is more fitted to adsorption capacity. The result IAC has shown the best performance for the removal ofthese priority water pollutants.