Investigation of Adsorption Performance of Biochar for Oil-Contaminated Wastewater Treatment

The discharge of oily wastewater from industrial, domestic, and petrochemical operations poses severe hazards to aquatic ecosystems and human health. In this study, a highly efficient biochar adsorbent was synthesized from agricultural waste (rice husk) via slow pyrolysis at ۶۰۰oC and subsequently activated using potassium hydroxide (KOH) to evaluate its adsorption performance for oil-contaminated wastewater treatment. The synthesized activated biochar (BC-KOH) was characterized utilizing Brunauer–Emmett–Teller (BET) surface area analysis, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Systematic batch adsorption experiments were performed to evaluate the effects of contact time, adsorbent dosage, initial oil concentration, pH, and temperature. Kinetic modeling showed that the adsorption process followed a pseudo-second-order model, suggesting chemisorption as the rate-limiting step. Equilibrium data were analyzed using Langmuir, Freundlich, and Temkin isotherm models, with the Langmuir model demonstrating an exceptional fit (R۲ = ۰.۹۹۴) and exhibiting a maximum monolayer adsorption capacity of ۱۸۴.۲ mg/g at ۴۵oC. Thermodynamic parameters (ΔG°, ΔH°, and ΔS°) confirmed that the oil adsorption process was spontaneous, endothermic, and governed by increased randomness at the solid-liquid interface. Reusability studies indicated that the activated biochar retained over ۸۲.۵% of its initial adsorption capacity after five regeneration cycles. These results demonstrate that KOH-activated rice husk biochar is an environmentally friendly, highly efficient, and economically viable platform for the treatment of oily wastewater

کلیدواژه ها:

Biochar ، Adsorption ، Oily Wastewater ، Kinetics ، Isotherms ، Thermodynamics