Facile preparation of micro-porous biochar from Bangladeshi sprouted agricultural waste (corncob) via in-house built heating chamber for cationic dye removal

Herein, in-house built heating chamber aided facile preparation of biochar was carried out using Bangladeshi sprouted corncob as the precursor for removing methylene blue (MB). The corncob biomass (CCB) was pyrolyzed at 700°C for 2hrs (heating rate: 10°C/min) using the in-house built heating chamber in a muffle furnace, eliminating the necessity of pyrolytic chamber. The prepared corncob biochar (CCBC) was characterized for elemental composition, crystallinity (XRD), functional groups (ATR-FTIR), surface morphology-elemental composition (SEM-EDX), surface area (BET), surface charge (point of zero charge), particle size-stability (DLS-zeta potential) and thermal stability (STA). Adsorption efficacy of CCBC was investigated in batch experiment with MB dye and effect of various factors such as contact time (5-120min), initial MB concentration (7-15mg/L), pH (2-10) and adsorbent dosage (10-35mg). Without any chemical treatment for activation, CCBC produced maximum adsorption capacity (Qmax) of 20.42mgg-1 at 25°C. The adsorption behavior of MB by CCBC could be better understood by Langmuir isotherm and Pseudo-second order kinetic model as they were the best fitted isotherm and kinetic models. Thus, waste to treat waste, meaning agricultural wastes like corncob can easily be converted into effective adsorbent for treating dye bearing wastewater.