Environmental study on lead emitted from lead battery industry and its removal by activated carbon

ABSTRACT

Three commercial activated carbons in powder and granular forms were used for the uptake of lead either from air or from aqueous medium. Batch equilibrium experiments have been carried out to optimize variables controlling the adsorption efficiency. The equilibrium time was to be about 12 hrs. However, more than 90% of the uptake is observed after 6 hrs. The uptake in all cases increases with the increase of pH to reach maximum at pH range 3.5-5.5. No trial has been made to follow lead uptake in the alkaline range because in this range lead is precipitated rather than adsorbed. For the same equilibrium time, the amount of lead adsorbed is higher for greater values of initial concentration. The adsorption isotherms of lead ions from aqueous solution are Langmuirian isotherms of type [L] according to Giles classification. The data obtained from the adsorption equilibrium experiments was found to fit Langmuir and Freundlich equations. The breakthrough curves were measured at 10 cm bed height and an initial lead concentration of 50 mg/l and a flow rate of 2 ml/min for the carbons used. The carbon sample [E] was used for the uptake of lead fumes from lead-acid battery workshops using packed column of 10 centimeters height. The concentrations of lead emitted from ten different workshops were measured twice per week for 4 hrs each day. However, regardless the high concentrations of lead emitted, a percent removal between 50 and 78% was achieved