Binary system dye removal from colored textile wastewater using activated carbon: Kinetic and isotherm studies

This paper investigates the ability of activated carbon (AC) to adsorb two anionic dyes from colored wastewater in single and binary systems. Direct Blue 78 (DB78) and Direct Red 31 (DR31) were used as anionic dye models. The surface characteristics of AC were investigated using fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The effects of AC dosage, initial dye concentration and salt on dye removal were investigated at 25 °C. The kinetic and isotherm of dye adsorption were studied. Adsorption kinetic of dyes was studied in single and binary systems and rate sorption was found to conform to pseudo — second order kinetic model. The isotherm data of dyes in single and binary systems followed Langmuir isotherm. The maximum adsorption capacity (Q 0) of DB78 and DR31 was 76.92 mg/g and 111 mg/g for single system and 76.92 mg/g and 125 mg/g for binary system, respectively. Results indicated that AC could be used as an adsorbent to remove the anionic dyes from single and binary pollutants systems. ► Adsorption kinetic of direct dyes in single and binary systems followed pseudo-second order. ► Isotherm data of direct dyes in single and binary systems followed Langmuir isotherm. ► AC could be used as an adsorbent to remove the anionic direct dyes from binary systems.