The organic dye malachite green (MG) poses a potential risk of cancer and fertility loss in humans and aquatic organisms. This study focused on a modified pyrolytic char (PC) derived from waste tires to efficiently remove MG from wastewater. Modified PC has rich -OH functional groups, higher BET (Brunauer-Emmett-Teller) surfaces of 74.4, 64.95, and 67.31 m2/g, and larger pore volumes of 0.52, 0.47, and 0.62 cm3/g for NaOH, Na2CO3, and CaO modification, respectively. The pseudo-second-order model fit the adsorption well, and the maximum equilibrium adsorption capacity was 937.8 mg/g for PC after CaO activation (CaO-PC). NaOH-modified PC (NaOH-PC) showed the best fit with the Langmuir model (R2 = 0.918). It is suggested that alkali-modified waste tire pyrolytic char could be a potential adsorbent for removing MG from dye-containing wastewater.
Keywords: adsorption; malachite green; metal oxide catalyst; pyrolytic char; waste tire.