Abstract
The removal of crystal violet (CV) dye from wastewater using biochar derived from various agricultural wastes increased interest among researchers. In this study, banana pseudo stem (BPS) waste was used as the feedstock for preparing biochar through slow pyrolysis at temperatures 300 (C, 500 (C, 700 (C and 900 (C. The adsorption screening results revealed that BPS biochar optimized at a pyrolysis temperature of 300 °C (denoted as BC300) exhibited the highest removal and amount of CV adsorbed with 96.4 % and 48.2 mg/g, respectively. Activation by chemical treatment with H2SO4, HCl, NaOH and KOH was then applied to the BC300 and the efficient removal of CV from the aqueous solution was investigated. The adsorption experiment showed that the removal percentage and amount of CV adsorbed with BC300 were significantly improved in the range of 14.0 % – 17.8 % and 0.7 mg/g – 1.2 mg/g, respectively, after chemical activation. In comparison to the other three activated biochar, BC300 biochar with H2SO4 treatment achieved the highest removal rate (98.4 %) and the highest quantity of CV adsorbed (9.8 mg/g). The findings preliminary indicate the potential of biochar derived from banana pseudo stem to be used as a promising adsorbent for removing CV. Activation by chemical treatment, preferably with H2SO4 enhanced the adsorption capability of the biochar thus resulting in a higher removal percentage of CV from the aqueous solution.
