Removal of lead from polluted water by adsorption on bentonite clay particles

Abstract EN

This study investigates the capability of a certain type of natural Bentonite clay to remove the poisonous element; lead, from polluted water by adsorption phenomena on the clay particles at different temperature levels.

Many high lead concentration synthetic solutions had been prepared in laboratory (24.3, 56.85, 146.55, 269.99, 284.72, 418.86, 465.61, 658.80 mg/L), and a volume of 250 ml from each solution being mixed with 2.5 g of Bentonite clay for a period of one hour at a certain temperature level (three levels were used, 20, 40, and 60 0C) and pH=7, until an equilibrium adsorption process being obtained, then the samples filtered through a porous paper, and the filtrate tested by atomic absorption technique to determine the remaining lead concentration.

Very high removal efficiencies have been obtained (more than 98%), and the results were drawn on graphs to show the relations at test conditions.

The above mentioned procedure was repeated using the same prepared lead solutions but mixed with 0.5 g of Bentonite clay and tested at temperature of 20 0C, and very good lead removals also were obtained.

The adsorbed lead ions mass in mg, on Bentonite mass in gram (Me) were ranged from 2.387 to 65.848 at temperature levels of 20, 40, 60 0C and Bentonite clay dosage of 2.5 g per 250 ml of polluted waters ranged in initial Lead concentrations from 24 to approximately 700 mg/L, and Me from 24.808 to 202.938 for dosage 0.5 g at 20 0C at same lead concentration range.

The Langmuir and Freundlich isotherm models for adsorption were used in analyzing the adsorption data and find their constants at different temperature levels to investigate if they can describe the obtained data well, Langmuir model was more representative of the data than Freundlich model.

Bentonite clay would be very efficient in removing lead from industrial wastewater.