Lead removal from aqueous solutions by use of new low-cost adsorbent

Recently several kinds of low-cost adsorbents were developed for the extreme environmental and waste treatment processes. In the present investigation commercial zeolite, bentonite and kaolin were used in experimental design algorithm due to their abilities in removal of heavy metal ions. Different amounts of used powders were mixed according to mixture design algorithm and shaped by extrusion technique in the form of Raschig ring. The test rings were calcined at 600 and 700 ºC after drying in laboratory oven. The adsorbent properties such as porosity, compressive strength and removal efficiency were measured. The response surface method was applied to analyze the obtained data. The investigation was concluded that the strength and adsorption capacity can be simultaneously optimized by the addition of 66.67, 29.17 and 4.16 wt.% zeolite, bentonite and kaolin respectively. In the next part of work, the kinetics and adsorption isotherm of lead on selected composition was mathematically investigated. The Langmuir isotherm and pseudo second order kinetic model showed the acceptable accuracy in prediction of adsorption data.