The adsorption of Cr(III) and As(III) by using coal ash from thermal power plants in batch mode ,The effect of adsorbent agitation speed, dose, pH, contact time and agitation speed on the adsorption of Cr(III) and As(III) by coal ash is examined. Adsorption equilibrium was achieved in 50–55 min. The Langmuir, Temkin and Freundlich adsorption isotherms were used to observed sorption phenomena. T...

Batch sorption experiments were carried out to remove As(III) from aqueous solution by using iron based commercial adsorbent Bayoxide. The effects of various experimental parameters, such as initial concentration, contact time and solution pH on the adsorption of As(III) on adsorbent was investigated. The adsorption density increased with increased initial arsenic concentration and contact time...

Currently, heavy metal-contaminated groundwater is an environmental concern. This study investigated the use of bamboo biochar, chitosan-impregnated and iron-impregnated biochar for arsenic, iron, manganese removal from groundwater. Isotherms adsorption by derived were compared with those commercial activated carbon in simulated composed single trinary metal solutions. The binding metals virgin...

Hydrogen adsorption on the ~234! and ~432! reconstructions of gallium arsenide ~001! has been studied by internal reflectance infrared spectroscopy and ab initio cluster calculations with density-functional theory. The calculations are made on Ga5As4H11,13, Ga4As5H11,13 , and Ga7As8H19 clusters, which model the arsenicand gallium-dimer termination of the semiconductor surface. Excellent agreeme...

A U.S. Geological Survey (USGS) study of the transport of anthropogenic and natural contaminants to public-supply wells (PSWs) in four aquifer systems documents the occurrence and distribution of arsenic and uranium, and determines some of the mechanisms for their mobilization and movement. The study areas include a glacial aquifer system in Woodbury, Connecticut (referred to herein as CT); the...

Results of first-principles calculations are reported for the adsorption of As2 molecules on the stable surface reconstructions of the GaAs (001) surface, including adsorption paths and barriers for strongly bound sites. It is shown that a novel chemisorption state acts together with an intermediate physisorbed plateau in the total energy to hold the As2 molecules near the surface and funnel th...

The response of Chlorella vulgaris when challenged by As(III), As(V) and dimethylarsinic acid (DMA) was assessed through experiments on adsorption, efflux and speciation of arsenic (reduction, oxidation, methylation and chelation with glutathione/phytochelatin [GSH/PC]). Our study indicates that at high concentrations of phosphate (1.62mM of HPO4(2-)), upon exposure to As(V), cells are able to ...