GALLIUM ARSENIDE (cas 1303-00-0) (GaAs) leaching behavior and surface chemistry changes in response to pH and O2

Add time:08/12/2019    Source:sciencedirect.com

GALLIUM ARSENIDE (cas 1303-00-0) (GaAs) is a material widely used in electronic devices. Disposal of electronic waste containing GaAs in municipal solid waste landfills raises concerns about the public health and ecological risks associated with the potential release of toxic arsenic (As) species. In this study, different tests were performed to investigate the leaching behavior of particulate GaAs in aqueous solutions. In the U.S. Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET), the concentrations of As released from the GaAs particles were about 2.6–2.8-fold higher than the regulatory limit (5 mg/L). A much higher As concentration (72 mg/L), accounting for as much as 15.4% of the initial As in GaAs, was solubilized in a pH-7.6 synthetic landfill leachate under ambient atmosphere after 120 days. Additional tests performed to evaluate the dissolution of GaAs under a range of redox conditions, pH levels, ionic strength, and presence of organic constituents commonly found in landfills revealed that oxic environments and mildly alkaline conditions (pH 8.1–8.5) promote release of As (chiefly arsenite) and gallium species to the surrounding aqueous environment. The rate of As release in long-term exposure experiments was initially constant but later progressively diminished, likely due to the formation of a passivating layer on the surface of GaAs consisting of corrosion products rich in poorly soluble gallium oxides (Ga2O3 and Ga(OH)3). This hypothesis was confirmed by surface analysis of GaAs particles subjected to leaching using X-ray photoelectron spectroscopy (XPS). These findings suggest that further research is needed to assess the potential release of toxic As from electronic waste in municipal landfills.

We also recommend Trading Suppliers and Manufacturers of GALLIUM ARSENIDE (cas 1303-00-0). Pls Click Website Link as below: cas 1303-00-0 suppliers

Prev:Analysis of recombination processes in polytype GALLIUM ARSENIDE (cas 1303-00-0) nanowires
Next:Photovoltaic solar cells based on graphene/GALLIUM ARSENIDE (cas 1303-00-0) Schottky junction)