Author(s): Nguyen Thi Hang Nga
Linked Author(s):
Keywords: Dsorption; Water treatment; Heavy metals; Lateirte soil; Iron oxides
Abstract: Heavy metal pollution in water is a great concern due to the potentially hazardous effects on the environment. Laterite soil is abundantly available natural material in tropical and sub-tropical, has high potentials in wastewater treatment due to consist of iron and aluminum oxides. The present study aims to evaluate the applied ability of laterite soils to replace costly chemical agents in heavy metal treatment in water. Application of laterite soil to remove heavy metal in water was identified by batch experiments of adsorption of Cu 2+, Pb 2+ and Cd 2+ were carried out at laboratory scale with artificial model solutions of heavy metals. The laterite samples collected from lateric soil zones in Viet Nam. Soil sample was air-dried at room temperature and ground. A particle fraction less than 2mm was used for adsorption experiments. Adsorption capacity was determined based on Langmuir models. The results showed that laterite soil has high adsorption capacity for lead (up to 1.0-1.2mg Pb g -1 at pH5). Adsorption capacity for copper, though not as high as that of lead, is acceptable if used in water treatment (about 0.5-0.8mg Cu g -1 at pH 5). Cadmium hardly is removed by laterite soil. The calculated adsorption capacities by laterite were0.4mg Cd g -1 at aninitial concentration of 25 mg L -1. This study shows that pH strongly effects on Cu (II), Pb (II) and Cd (II) adsorption on laterite adsorbents. At pH s lower than 4, these materials were not effective for metals removal. From a viewpoint of implementation, the laterite should be used after pH adjustment to over 4 for Pb, Cu, Cd removal from wastewater. The study was conducted at a constant initial metal ion concentration of 10 mg L -1. The adsorbent dose was1g-2g of laterite samples and the reaction time of 8-12 h are optimal conditions for adsorption.
Year: 2014