Adsorption of Chromium from Aqueous Solution by Steel Slag: Kinetic Modeling and Isotherm Adsorption

One of the main environmental pollutants is the existence of heavy metals in the industrial wastewater. Chromium is among the heavy metals found in industrial wastewater. It is toxic and dangerous for people and environment. The steel slag is the main by-product of steel industry. The aim of this study was removing heavy metal such as Chromium by using the steel slag as a low-cost adsorbent from aquatic environment. Some factors that affect the process of Chromium removal by steel slag such as pH, contact time, adsorbent dosage and cadmium initial concentration were studied. Standard solution of synthetic wastewater including Chromium was prepared by adding Potassium Dichromate to distilled water and concentrations in the range of 5-25 mg/l. The results showed that in optimum conditions, the removal of Chromium from aqueous solution with concentration of 25mg/l, pH=7, adsorbent equal to 3gr and 60min contact time is about 99%. The experimental data of adsorption equilibrium were analyzed on the basis of adsorption kinetics models and Freundlich and Langmiur adsorption isotherms. Maximum adsorption capacity by Langmiur model was. /97mg/g a nd correlation factor in kinetic pseudo-second order model turned out to be1. The physical, chemical and morphological features of the steel slag were also determined by XRD, XRF and SEM techniques. The results of this study could be useful in using steel slag for removing Chromium from aqueous solution.