Abstract
Adsorption is becoming an important method in water and wastewater treatment technology at low concentrations. Pb2+ adsorption at low concentration onto various solid surfaces using either nano metal oxide of MnO2, or granulated activated carbon (GAC) or agricultural by-products such as tea leaves and coffee residue are considered promising. In this adsorption study the measurements were conducted by equilibrating Lead solutions at different concentrations range 19 - 291 μmol·L-1 with various adsorbent suspensions in the concentration range 0.388 - 8.738 g·L-1. Comparing all the adsorption capacities calculated using Langmuir equation Pb2+ adsorption by MnO2 shows the highest adsorption capacity with the estimated Γm = 528.0 μmol·g–1 at a fixed equilibrium constant K = 0.0119 L·μmoL-1. In addition, the Pb2+ adsorption by coffee residue is subject to a particle concentration effect in which the adsorption density decreases as the concentration of solid adsorbent Cs is increased. The Pb2+ adsorption by tea leaves, MnO2 and GAC shows less dependency to the concentration of solid adsorbent Cs, especially at lower metal ion concentrations. In the particular case of Pb2+ adsorption on MnO2 there appears to be no dependence on Cs.
Highlights
Lead is among the most toxic heavy metal ion affecting the environment [1]
More variations of coffee grounds concentration were used to clearly discuss a particle concentration effect found in this particular adsorption study
The result was expected in such cases that different concentrations of each adsorbent Cs equilibrated with Pb2+ ranging from 19 to 291 μmol∙L–1 fit into a single Langmuir model, i.e. single values of K and Γm for each type of adsorbent
Summary
Lead is among the most toxic heavy metal ion affecting the environment [1]. It may come into waterways through the combustion of fossil fuels and the smelting of sulphide ore, and into lakes and streams by acid mine drainage. Process industries, such as battery manufacturing and metal plating and finishing are prime source. The stringent requirement for lead in aquatic environment has triggered some wastewater engineer to work harder in searching for inexpensive material and technology to uptake lead pollutants from water and wastewater
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