Evaluation of some Rocks and Clay Mineral in Adsorption of Cadmium from Wastewater of Chemical Complex of Phosphate in Iraq

Abstract

The presence of high concentration of cadmium (Cd) in the by-product treated wastewater of phosphate industry in west of IRAQ caused real heavy metal pollution for soil, water resources, and crops in the area. Accordingly, the aim of this study is to evaluate the effective method to reduce cadmium concentration of treated wastewater. Four locally available materials namely rock phosphate, bentonite clay, lime and silicate rocks were evaluated as cadmium adsorbing agents. Effect of weight and piratical size in Cd adsorption capacity of each material were also evaluated. Results showed that adsorption capacity of the tested materials in the following order: rock phosphate> bentonite clay> lime> silicate rocks. Results also showed that the that the best size making higher adsorbing is < 0.1 mm, then 0.1 – 0.5 mm and then 0.5 – 1.0 mm. Also, the amount of Cd adsorbed by each material increase with the increase of weight of adsorbing material added per unit of wastewater. Amount of Cd adsorbed in relation to weigh of material added is in the following order: 0.5 gm > 0.25 gm > 0.1gm. While the adsorbing decrease with the increase of material particle size. Also First order equation was the best fit equation which is described the adsorption of cadmium in four tested materials, particles size and weights of materials added.