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.

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.

Aplikasi Pendayagunaan Asam In-Situ pada Kulit Pikel Terbuang untuk Pembuatan Gelatin Pangan

2016 ◽  
Vol 9 (2) ◽  
pp. 187-197
Author(s):  
Sugihartono Sugihartono
Keyword(s):  
Food Industry ◽  
Type A ◽  
Collagen Fibers ◽  
Final Phase ◽  
Acid Base ◽  
Salt Hydrate ◽  
Food Grade ◽  
Hydrolyze Collagen ◽  
Waste Acid

Skinswaste at pre-tanning operations can be processed into food grade gelatin. The degradation of collagen using acid, base, or enzymes produced gelatin. Pickle skins is skins that acidified, the results of the final phase of the pre-tanning operations. The addition of salt on the skin makes the skins pickle not swollen, produced a wide space between collagen fibers and collagen can not be degraded. Thereby directly extract pickle skins or waste will not be obtained gelatin.This study discussed the processing of food gelatin type A pickle skins through the utilization of waste acid it contains. The discussion includes the components of animal skins, pre-tanning waste, acidification of skins, processing gelatin and gelatin from skins picklewaste and usefulness for the food industry. Salt hydrate collagen fibers in the skin pickle including waste can be separated by washing, to a certain extent still acidic skins waste. The remaining acid on the skins pickle waste can be utilized to hydrolyze collagen into gelatin. The resulting gelatin is gelatin type A, that can be used for food industry.ABSTRAKKulit limbah pada operasi pra-penyamakan dapat diolah menjadi gelatin pangan. Pemecahan kolagen menggunakan asam, basa, atau enzim dihasilkan gelatin. Kulit pikel merupakan kulit yang diasamkan, hasil dari tahap akhir operasi pra-penyamakan. Penambahan garam pada kulit pikel menjadikan kulit tidak bengkak, menghasilkan ruang lebar diantara serat kolagen dan menjadikan kolagen tidak dapat terdegradasi. Hal ini berarti ekstrak secara langsung kulit pikel atau limbahnya tidak akan diperoleh gelatin. Dalam kajian ini dibahas pengolahan gelatin pangan tipe A dari kulit pikel limbah melalui pendayagunaan asam yang dikandungnya. Bahasan mencakup komponen kulit hewan, limbah pra-penyamakan, pengasaman kulit, pengolahan gelatin, dan pengolahan gelatin dari kulit pikel limbah melalui pendayagunaan asam yang dikandungnya serta kegunaannya untuk industri pangan. Garam yang menghidrasi serat kolagen pada kulit pikel termasuk limbahnya dapat dipisahkan dengan cara pencucian, sampai batas tertentu kulit limbah masih bersifat asam. Asam yang tersisa pada kulit pikel limbah tersebut dapat didayagunakan untuk menghidrolisis kolagen menjadi gelatin. Gelatin yang dihasilkan adalah gelatin tipe A, dapat digunakan untuk keperluan industri pangan. Kata kunci : Kulit pikel limbah, gelatin, pengasaman, pangan.

NITROGEN CYCLING IN HIGH ARSENIC GROUNDWATER SYSTEM

2020 ◽  
Author(s):  
Zhipeng Gao ◽  
◽  
Haicheng Weng ◽  
Huaming Guo
Keyword(s):  
Nitrogen Cycling ◽  
Groundwater System ◽  
High Arsenic ◽  
High Arsenic Groundwater

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.

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