A circular economy approach in converting food (chicken rice) waste into activated carbon for optimise removal of methyl violet dye by Box-Behnken Design

Herein, a mixed left-over food waste of chicken bone and rice waste (CKBR) was transformed into mesoporous activated carbon (CKBR-AC) via microwave- assisted ferric chloride (FeCl 3 ) activation. The physical and chemical properties of CKBR-AC were investigated by various analytical techniques including specific surface area analysis (BET), pH pzc , XRD, FTIR, and FSEM-EDX. The adsorptive performance CKBR-AC towards methyl violet (MV) dye was investigated and optimised by using Box–Behnken design (BBD) and desirability function approach. The best MV removal under optimal desirability function conditions (CKBR-AC dosage = 0.19 g/ 100 mL, MV solution pH = 8, and contact time of 468 min) was found to be 89.3%. The profiles of the adsorption isotherm and kinetic of MV dye adsorption by CRW-AC were best fitted to Langmuir isotherm model and the pseudo-second order (PSO) kinetic model, respectively. The maximum adsorption capacity ( q max ) of CKBR-AC for MV dye was reported 37.5 mg/g. Hence, multiple mechanisms approaches can support the MV dye loading onto CKBR-AC surface including π-π attraction, electrostatic interaction, and hydrogen bonding. Thus, the findings of this study demonstrate the effectiveness of CKBR-AC to be a potential and reusable adsorbent for toxic cationic (MV) dye removal from aqueous environment.