Biochar from Manihot esculenta stalk as potential adsorbent for removal of reactive yellow dye

Abstract

Textile effluent treatment is crucial for a cleaner and safer community. The purpose of this study is to utilize biochar prepared from Manihot esculenta stalk to remove reactive yellow dye through Pyrolysis at 350 °C for 210 min. The effect of quantity of adsorbent, pH values of the adsorbate solution experimented, contact time required, starting dye concentration, current temperature of the solution, speed of agitation, as well as size of the particle on reactive yellow dye removal was examined using biochar through batch trials. At an equilibrium period of 25 min, pH of 7, bio-char dosage of 2 g, temperature of 25 °C, agitation speed of 150 rpm, as well as particle size of 231 µm, 86% of the dye could be removed with highest adsorption capacity of 53.47 mg/g. Pseudo-first order type kinetics in addition to the Langmuir isotherm model were set up to finest fit the adsorption model of reactive yellow dye onto biochar from M. esculenta stalk. The process is chemisorption, exothermic, feasible, and spontaneous, as it is predicted by the thermodynamically negative enthalpy as well as entropy of adsorption values. The spent M. esculenta stalk biochar was reused for six cycles of adsorption at same optimal process conditions and adsorption capacity was found to be insignificant up to fourth cycle. Also, M. esculenta biochar was characterized through scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDAX) and Fourier Transform Infrared Spectroscopy (FTIR) for morphology, elemental composition, and functional groups respectively. So, the M. esculenta stalk biochar could be an active adsorbent for elimination of reactive dye from the solution of dye.