Arsenic (V) removal from groundwater by GE-HL nanofiltration membrane: effects of arsenic concentration, pH, and co-existing ions

The detoxification capacity of the liver is well documented for a variety of substances including ethanol, organic pesticides, drugs, and metals. The piscean liver, although less enzymatically active than the mammalian counterpart (1), contains endoplasmic reticulum with an impressive repertoire of oxidizing, reducing, and conjugating abilities (2). Histopathologic changes are kncwn to occur in fish hepatocytes following in vivo exposure to arsenic (3); however, ultrastructural changes have not been reported. This study involved the morphometric analysis of intracellular changes in fish parynchymal hepatocytes and correlation with arsenic concentration in the liver.Green sunfish (Lepomis cyanellus, R.) were exposed to 0, 30, or 60 ppm arsenic (as sodium arsenate) at 20°C for 1, 2, or 3 week intervals before removal of livers for quantification of the arsenic burden (using neutron activation analysis) and morphometric analysis of ultrastructural alterations. Livers were cut into 1 mm cubes for fixation, dehydration, and embedding.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126548 ◽

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.

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CHARACTERIZATION STUDIES OF A NEW CERAMIC NANOFILTRATION MEMBRANE WITH FOULING RESISTANT PROPERTIES FOR EFFICIENT WATER TREATMENT

Environmental Engineering and Management Journal ◽

10.30638/eemj.2016.175 ◽

2016 ◽

Vol 15 (7) ◽

pp. 1629-1634

Author(s):

Mihaela-Elena Dascalu ◽

David Amaya Vias ◽

Valentin Nedeff ◽

Juan Antonio Lopez-Ramirez

Keyword(s):

Water Treatment ◽

Nanofiltration Membrane ◽

Characterization Studies

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As(III) Removal by Dynamic Adsorption onto Amberlite XAD7 Functionalized with Crown Ether and Doped with Fe(III) Ions

Revista de Chimie ◽

10.37358/rc.19.7.7333 ◽

2019 ◽

Vol 70 (7) ◽

pp. 2330-2334

Author(s):

Mihaela Ciopec ◽

Adina Negrea ◽

Narcis Duteanu ◽

Corneliu Mircea Davidescu ◽

Iosif Hulka ◽

...

Keyword(s):

Adsorption Process ◽

Arsenic Removal ◽

Arsenic Concentration ◽

Fixed Bed ◽

World Health ◽

Arsenic Content ◽

Arsenic Adsorption ◽

Stage Of Development ◽

Wide Range ◽

Health Organization

Arsenic content in groundwater�s present a wide range of concentration, ranging from hundreds of micrograms to thousands of micrograms of arsenic per litter, while the maximum permitted arsenic concentration established by World Health Organization (WHO) is 10 mg L-1. According to the WHO all people, regardless of their stage of development and their social economic condition, have the right to have access to adequate drinking water. The most efficient and economic technique used for arsenic removal is represented by adsorption. In order to make this remediation technique more affordable and environmentally friendly is important to new materials with advance adsorbent properties. Novelty of present paper is represented by the usage of a new adsorbent material obtained by physical - chemical modification of Amberlite XAD polymers using crown ethers followed by iron doping, due to well-known affinity of arsenic for iron ions. Present paper aims to test the obtained modified Amberlite polymer for arsenic removal from real groundwater by using adsorption in a fixed bed column, establishing in this way a mechanism for the adsorption process. During experimental work was studied the influence of competing ions from real water into the arsenic adsorption process.

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