A Statistical Modeling and Optimization for Cr(VI) Adsorption from Aqueous Media via Teff Straw-Based Activated Carbon: Isotherm, Kinetics, and Thermodynamic Studies

Currently, the growth of tannery industries causes a significant volume waste disposal to environment due harmful Cr(VI). Long-time exposure Cr(VI) imposes serious hazards on all living organisms. Hence, treatment remove is not choice but mandatory. Therefore, this study focused removal from aqueous solutions via teff (Eragrostis tef) straw based-activated carbon (TSAC) which was derived locally available agricultural solid waste, (TS). The prepared TSAC characterized using BET, FTIR, SEM, and XRD. A central composite approach-based RSM analysis undertaken for statistical modeling optimization maximized with respect four important factors, namely, initial concentration Cr(VI), dosage TSAC, pH, adsorption time. Optimized values maximizing (95% removal) were acquired be concentration: 87.57 mg/L, dosage: 2.742 g/100 mL, pH: 2.2, contact time:109 min. results design experiment also analyzed significance interaction between selected process parameters. In addition, pseudo-second-order kinetic Langmuir isotherm models found suitable describing data. capacity 19.48 mg/g. observed thermodynamic characteristics reveal that TASC endothermic in nature. From results, had shown potential efficiency optimized conditions can exploited effectively as adsorbent Cr(VI)-contaminated wastes.