A Novel Process for the Treatment of Copper-Smelting Waste Acid with a High Arsenic Concentration

JOM ◽  
2018 ◽  
Vol 70 (10) ◽  
pp. 2022-2026 ◽  
Author(s):  
Tianzu Yang ◽  
Bin Hu ◽  
Weifeng Liu ◽  
Duchao Zhang ◽  
Lin Chen
Keyword(s):  
Arsenic Concentration ◽  
Copper Smelting ◽  
High Arsenic ◽  
Waste Acid

Study of dislocation loops in Arsenic-Rich as-grown GaAs

1987 ◽  
Vol 45 ◽  
pp. 350-351
Author(s):  
Byung-Teak Lee
Keyword(s):  
Point Defects ◽  
Electronic Devices ◽  
Arsenic Concentration ◽  
Stoichiometric Compound ◽  
Dislocation Loops ◽  
Gaas Crystal ◽  
Ion Milling ◽  
Transmission Electron ◽  
Arsenic Source ◽  
High Arsenic

Grown-in dislocations in GaAs have been a major obstacle in utilizing this material for the potential electronic devices. Although it has been proposed in many reports that supersaturation of point defects can generate dislocation loops in growing crystals and can be a main formation mechanism of grown-in dislocations, there are very few reports on either the observation or the structural analysis of the stoichiometry-generated loops. In this work, dislocation loops in an arsenic-rich GaAs crystal have been studied by transmission electron microscopy.The single crystal with high arsenic concentration was grown using the Horizontal Bridgman method. The arsenic source temperature during the crystal growth was about 630°C whereas 617±1°C is normally believed to be optimum one to grow a stoichiometric compound. Samples with various orientations were prepared either by chemical thinning or ion milling and examined in both a JEOL JEM 200CX and a Siemens Elmiskop 102.

scholarly journals Synonymous single nucleotide polymorphism in arsenic (+3) methyltransferase of the Western mosquitofish (Gambusia affinis) and its gene expression among field populations

Ecotoxicology ◽  
2021 ◽  
Author(s):  
Daesik Park ◽  
Catherine R. Propper ◽  
Guangning Wang ◽  
Matthew C. Salanga
Keyword(s):  
Gene Expression ◽  
Sequence Variation ◽  
Allelic Variation ◽  
Arsenic Concentration ◽  
Gambusia Affinis ◽  
Contamination Level ◽  
Water Medium ◽  
Single Nucleotide ◽  
Wide Range ◽  
High Arsenic

AbstractNaturally occurring arsenic is toxic at extremely low concentrations, yet some species persist even in high arsenic environments. We wanted to test if these species show evidence of evolution associated with arsenic exposure. To do this, we compared allelic variation across 872 coding nucleotides of arsenic (+3) methyltransferase (as3mt) and whole fish as3mt gene expression from three field populations of Gambusia affinis, from water sources containing low (1.9 ppb), medium-low (3.3 ppb), and high (15.7 ppb) levels of arsenic. The high arsenic site exceeds the US EPA’s Maximum Contamination Level for drinking water. Medium-low and high populations exhibited homozygosity, and no sequence variation across all animals sampled. Eleven of 24 fish examined (45.8%) in the low arsenic population harbored synonymous single nucleotide polymorphisms (SNPs) in exons 4 and/or 10. SNP presence in the low arsenic population was not associated with differences in as3mt transcript levels compared to fish from the medium-low site, where SNPs were noted; however, as3mt expression in fish from the high arsenic concentration site was significantly lower than the other two sites. Low sequence variation in fish populations from sites with medium-low and high arsenic concentrations suggests greater selective pressure on this allele, while higher variation in the low population suggests a relaxed selection. Our results suggest gene regulation associated with arsenic detoxification may play a more crucial role in influencing responses to arsenic than polymorphic gene sequence. Understanding microevolutionary processes to various contaminants require the evaluation of multiple populations across a wide range of pollution exposures.

scholarly journals Urinary arsenic concentration in a high arsenic area of south west England.

1997 ◽  
Vol 54 (11) ◽  
pp. 840-840 ◽  
Author(s):  
P Kavanagh ◽  
M E Farago ◽  
I Thornton ◽  
P Elliott ◽  
W Goessler ◽  
...  
Keyword(s):  
Arsenic Concentration ◽  
Urinary Arsenic ◽  
South West ◽  
South West England ◽  
High Arsenic

scholarly journals Disposal of high-arsenic waste acid by the stepwise formation of gypsum and scorodite

RSC Advances ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Xianjin Qi ◽  
Yongkui Li ◽  
Longhua Wei ◽  
Fengyan Hao ◽  
Xing Zhu ◽  
...  
Keyword(s):  
Stepwise Formation ◽  
High Arsenic ◽  
Waste Acid

Arsenic is removed from high arsenic waste acid via the stepwise formation of gypsum and scorodite.

An effective separation process of arsenic, lead, and zinc from high arsenic-containing copper smelting ashes by alkali leaching followed by sulfide precipitation

2020 ◽  
Vol 38 (11) ◽  
pp. 1214-1221
Author(s):  
Yuhui Zhang ◽  
Xiaoyan Feng ◽  
Bingjie Jin
Keyword(s):  
Separation Efficiency ◽  
Separation Process ◽  
Copper Smelting ◽  
Solid Ratio ◽  
Effective Separation ◽  
Lead And Zinc ◽  
Valuable Metals ◽  
Alkali Leaching ◽  
Sulfide Precipitation ◽  
High Arsenic

Separation of arsenic and valuable metals (Pb, Zn, Cu, Bi, Sn, In, Ag, Sb, etc.) is a core problem for effective utilization of high arsenic-containing copper smelting ashes (HACSA). This study developed an effective separation process of arsenic, lead, and zinc from HACSA via alkali leaching followed by sulfide precipitation. The separation behaviors and optimum conditions for alkali leaching of arsenic and sulfide precipitation of lead and zinc were established respectively as follows: NaOH concentration 3.81 M; temperature 80°C; time 90 minutes; liquid-to-solid ratio 4:1; agitation speed 450 revolutions/minute (r/min) and 2.0 times of theoretical quantity of sodium sulfide (Na2S); temperature 70°C; and time 60 minutes. The results indicated that the leaching rates of As, Pb, and Zn were 92.4%, 36.9% and 13.4%, respectively. More than 99% of lead and zinc were precipitated from the alkali leachate. The scanning electron microscopy/energy dispersive X-ray spectroscopy study confirmed that arsenic was dissolved from HACSA into the alkali leachate. Furthermore, lead and zinc were precipitated as sulfides from the alkali leachate. The proposed process was a good technique for separation of arsenic and enrichment of valuable metals for further centralized treatment separately. It provided high separation efficiency of arsenic and valuable metals, as well as low environmental pollution.

scholarly journals Groundwater Arsenic Distribution in India by Machine Learning Geospatial Modeling

2020 ◽  
Vol 17 (19) ◽  
pp. 7119 ◽  
Author(s):  
Joel Podgorski ◽  
Ruohan Wu ◽  
Biswajit Chakravorty ◽  
David A. Polya
Keyword(s):  
Drinking Water ◽  
Urban Areas ◽  
Arsenic Concentration ◽  
Environmental Parameters ◽  
Predictor Variables ◽  
High Exposure ◽  
Rural And Urban Areas ◽  
Rural And Urban ◽  
Environmental Public Health Tracking ◽  
High Arsenic

Groundwater is a critical resource in India for the supply of drinking water and for irrigation. Its usage is limited not only by its quantity but also by its quality. Among the most important contaminants of groundwater in India is arsenic, which naturally accumulates in some aquifers. In this study we create a random forest model with over 145,000 arsenic concentration measurements and over two dozen predictor variables of surface environmental parameters to produce hazard and exposure maps of the areas and populations potentially exposed to high arsenic concentrations (>10 µg/L) in groundwater. Statistical relationships found between the predictor variables and arsenic measurements are broadly consistent with major geochemical processes known to mobilize arsenic in aquifers. In addition to known high arsenic areas, such as along the Ganges and Brahmaputra rivers, we have identified several other areas around the country that have hitherto not been identified as potential arsenic hotspots. Based on recent reported rates of household groundwater use for rural and urban areas, we estimate that between about 18–30 million people in India are currently at risk of high exposure to arsenic through their drinking water supply. The hazard models here can be used to inform prioritization of groundwater quality testing and environmental public health tracking programs.

Understanding the thermal decomposition of gold concentrates with high arsenic concentration

2018 ◽  
pp. 44-48
Author(s):  
P. A. Gulyashinov ◽  
◽  
P. L. Paleev ◽  
A. K. Subanakov ◽  
A. N. Gulyashinov ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Arsenic Concentration ◽  
High Arsenic

Treatment Mechanisms and Operation Conditions of Arsenic Removal from Copper Smelting Effluent Using Combined Process of Aeration Micro-Electrolysis and Flocculation

2012 ◽  
Vol 610-613 ◽  
pp. 2307-2318
Author(s):  
Yu Qi Liu ◽  
Yue Bin Feng ◽  
Xin Ying Wang ◽  
Jing Wang ◽  
Xiao Jun Xu
Keyword(s):  
High Efficiency ◽  
Arsenic Removal ◽  
Arsenic Concentration ◽  
Effluent Treatment ◽  
Treated Wastewater ◽  
Copper Smelting ◽  
Wastewater Discharge ◽  
Combined Process ◽  
Operation Conditions ◽  
Treatment Mechanisms

An effective combined process of aeration micro-electrolysis and flocculation was utilized to treat arsenic that incoming contaminate level was 153 mgL-1 from the metallurgical effluent. Treatment mechanisms and operation conditions were discussed which influenced the removal efficiency of arsenic. Under the optimal technological conditions, it was found that the removal efficiencies of COD and As were 92.5% and 99.7% respectively. The remain arsenic concentration in the treated wastewater was only 0.43mgL-1 and met National Wastewater Discharge Standard(GB8978-1996) in China. Analysis by SEM and EDS revealed that using combined process, most of As(III) could be oxidized to As(V), which led to the high efficiency of arsenic removal. In the meantime, most of other heavy metals, such as Cu, Pb and Ni, had been removed. Therefore, the combined process is regarded as a promising technology in the treatment of arsenic from copper smelting effluent. It has bright future in application.

Sign in / Sign up

Export Citation Format

Share Document