Equilibrium, kinetic and thermodynamic studies on the adsorption of thiocyanate by Steel slag in an Aqueous System

The use of steel slag in an adsorption process for the removal of thiocyanate has been studied for the first time. Steel slag, a readily available by-product of the steel industry, can be a suitable candidate for the study of the adsorption of thiocyanate found in coke oven effluent. The parameters considered for adsorption studies were pH, initial concentration, temperature, and the amount of adsorbent. It was found that the percentage removal of thiocyanate decreased with an increase in the initial concentration of thiocyanate. The rate of adsorption of thiocyanate increased with an increase in temperature. The adsorption process was spontaneous and exothermic in nature. The Langmuir isotherm was found to be the best fit for the adsorption process. The kinetic data follows the pseudo-second-order model. Main effect and interaction studies were done using the fractional factorial method. The FTIR studies confirmed that functional groups participated in the adsorption process. This made the steel slag a suitable adsorbent for the removal of thiocyanate.