Blended lignocelluloses Hevea brasiliensis and Helianthus annuus seed pericarps as a sustainable activated carbon precursor: a thermochemical synthesis and optimization for fuchsin dye removal.

Abstract

Herein, blended rubber seed pericarp (RSP) and sunflower seed pericarp (SFSP) were converted into mesoporous activated carbon adsorbent (RSPSFSP-AC) to remove a toxic cationic dye namely fuchsin basic (FB) dye from aqueous environment. The thermochemical conversion process was carried out by using microwave irradiation assisted ZnCl₂ activation for 15 min with 800 W. The physicochemical properties of RSPSFSP-AC were evaluated using several analytical techniques, including pH_pzc, BET, FTIR, and SEM-EDX analysis. The adsorptive property of RSPSFSP-AC for FB removal was evaluated and optimized by using the Box-Behnken design (BBD) and desirability function. The desirability function optimal conditions for FB removal (92.8%) were found to be 0.09 g/100 mL of RSPSFSP-AC dosage and 9.2 solution pH. The adsorption kinetic isotherm of the FB dye was explained by the pseudo-second order (PSO) model and Langmuir isotherm model respectively. The maximum adsorption capacity (q_max) of RSPSFSP-AC for the FB dye was found to be 147.7 mg/g. The adsorption of the FB dye onto the RSPSFSP-AC surface can be explained by several possible interactions including π-π stacking, electrostatic forces, pore filling, and hydrogen bonding. Thus, the output of this research work shows the potential applicability of RSPSFSP-AC for capturing cationic dye from an aqueous environment.