Response surface methodology for optimizing pollutants elimination from wastewater using activated biochar derived from mixed biowastes

The present study explores the co-carbonization of mixed date palm pits (DPPs) with chicken bones (CBs) in a fixed-bed reactor. The resulting biochar (BC) was successfully converted into activated biochar (ABC) using ZnCl₂ as an activator. The optimal ABC was produced using a 2:1 ZnCl₂:BC impregnation ratio at 500 °C for 60 min and 10 °C/min heating rate. The BET-specific surface area for this ABC was 531 m²/g, while its average pore diameter was 2.649 nm, signifying its mesoporous structure. The adsorption performance of chromium ion Cr (VI) and methylene blue (MB) from wastewater was examined using Box-Behnken Design (BBD) to obtain the optimal preparation conditions. The outcomes disclosed that under the ideal experimental settings (0.25 g of ABC for 180 min at 30 °C), the highest adsorptive removal of 100 mg/L Cr (VI) solution was 86.89 %. In comparison, the highest adsorptive removal of 200 mg.L⁻¹ MB solution was 99.75 % utilizing 0.25 g of ABC for 30 min at 30 °C. The Frundlich isotherm model was determined to be a suitable fit for the experimental data. The kinetics investigation found that a pseudo-2nd-order model best suited the data, indicating chemisorption. In conclusion, mixed DPPs+CBs can be adopted as a potential and effective precursor for producing ABC with a sustainable and adsorptive material.