Year: 2012
Type: dissertation
Abstract: Environmentally friendly treatment methods for heavy metals prior to discharge are \nconsidered favourable so as to protect ecosystems. The performance of modified zeolite from \ntwo different sources (South African and the USA) for the adsorption of Ni2+, Cd2+ and Pb2+ \nfrom synthetic industrial effluent contaminated with metal concentration levels at 50, 150 and \n500mg/L was assessed. The selectivity of the zeolite for the adsorption of Ni2+, Cd2+ and Pb2+ \nwas investigated at mixed feed solutions containing all three ions in equal concentrations and \nsingle component concentrations containing only one of the ions. The homoionic forms of the \nzeolite were made Na+, K+ and Ca2+. Batch experiments were then conducted to measure the \nuptake of metals by the zeolites. The zeolites were characterised using XRD and BET. The \nSouth Africa clinoptilolite has a higher surface area and pore volume (17.52m2/g and \n0.047cm3/g respectively) than the USA zeolite (12.26m2/g and 0.028cm3/g respectively) for \nthe Na+ homoionic form. According to the equilibrium studies, the selectivity sequence can \nbe given as Pb2+ >Cd2 >Ni2+, with good fits being obtained using Langmuir and Freundlich \nadsorption isotherms for low metal concentrations as compared to higher concentrations. The \nadsorption was found to depend on the homoionic form of the zeolite and to a lesser extent \nthe source of the zeolite. The selectivity of a particular zeolite for a particular heavy metal \ncan be altered by the homoionic form of the zeolite. Generally, the adsorption capacity of the \nUSA clinoptilolite is higher than the capacity of the RSA clinoptilolite revealing the potential \nof clinoptilolite in industrial effluent treatment.
Author: Blessing Taenzana
Language: English
Subfield: Water Science and Technology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W133505415