Biosorption of Lead from Aqueous Solutions using Egg Shell Powder as Biosorbent: Equilibrium Modelling

摘要

Current technologies for removal and recovery of both toxic and industrial metals usually produce wastes with high concentrations of those substances. They are an important source of environmental pollution, especially when they contain heavy metals.This is one of the most important environmental problems, and of the most difficult to solve. So far, there have been a number of studies considering the possibility of removing and recovering heavy metals from diluted solutions. These are due, principally, because of the commercial value of some metals as well as the environmental impact caused by them. The traditional methods for removing have several disadvantages when metals are present in concentrations lower than 100 mg/1. Biosorption is becomingan important component in the integrated approach to the treatment of aqueous effluents. The economics of biomass technical applications are improved by using waste biomass instead of purposely-produced biomass. Hen eggshell powder was investigated for its ability to remove lead from aqueous solution in a batch biosorption system. The biosorption performance of eggshell was examined by varying the process parameters like pH of the solution, contact time, lead ion concentration, sorbent concentration andsorbent size. The biosorption capacity of lead ions onto eggshell powder was evaluated. The Langmuir, Freundlich, Redlich-Peterson and Temkin biosorption models were applied to describe the isotherms and isotherm constants. Biosorption isothermal data could be well interpreted by the Freundlich model followed by Langmuir and Temkin models with maximum biosorption capacity of 29.87mg/g.