This paper presents the effect of pH and redox potential on the potential mobility of arsenic (As) from a contaminated mineral processing waste. The selected waste contained about 0.47 g kg(-1) of As and 66.2 g kg(-1) of iron (Fe). The characteristic of the waste was identified by acid digestion, X- …
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— The choice of a sulfuric acid or alkaline method of waste processing is defined by the technological possibilities of separating arsenic from the resulting …
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— The oxidation process was performed by continuous EC of the applied aerobic iron because it occurs in the electrochemical reactor (see Fig. 3) and average arsenic sludge generated from the process (35.8–70.64 mL L-1 per cycle). The oxidation process represents electrochemical coagulation, and As(III) oxidizes at pH conditions of …
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— F.D.A. inspectors also said that the supplier, Valley Processing of Sunnyside, Wash., used rotting or moldy apples and pears, in addition to expired concentrate, to make juice.
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In the present investigation, growth of the organisms was reduced due to presence of arsenic (III) and (V) in the culture medium. In comparison to arsenic (V), arsenic (III) had more toxic effect on microalgae. Among the different algal strains, blue green algal species Oscillatoria-Lyngbya mixed cu …
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— Abstract— This paper presents results of analysis of the patent, scientific, and technical literature concerned with the physicochemical and technological foundations of the preparation of high-purity arsenic-containing compounds from various raw materials. Considerable attention is paid to processing of unconventional raw materials (ite …
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— Karst terrains provide drinking water for about 25% of the people on our planet, particularly in the southwest of China. Pollutants such as arsenic (As) in the soil can …
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— The solution used for arsenic precipitation process is a mixture of the solution after copper precipitation and washing solution in the copper precipitation process, and the chemical composition is presented in Table 11. The contents of Zn, As T and As(III) were 19.88, 11.86 and 4.75 g/L, respectively.
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— In bacteria, the arsenic resistance system (ars) operon is located in chromosomes or plasmids. The ars genes function as detoxifiers of inorganic arsenic compounds. In the detoxification process of As(III), the extrusion of As(III) is catalyzed by the arsenite efflux permease (Ars B), which is encoded by the ars B gene of the ars …
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The direct application of arsenic in the form of pesticides, fungicides or wood preservatives has historically been a major source of arsenic in soils, as arsenic is strongly attracted to soil particles and sediments.
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— With new environmental legislation, demand arose for a simple and low-cost technology for arsenic waste processing into the disposable form. One of the cheapest methods consists of precipitation with lime. It has been proven however, that resulting solids are unstable when exposed to atmospheric carbon dioxide [1].
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Arsenic is a worldwide environmental pollutant and a human carcinogen. It is well recognized that the toxicity of arsenicals largely depends on the oxidoreduction states (trivalent or pentavalent) and methylation levels (monomethyl, dimethyl, and trimethyl) that are present during the process of metabolism in mammals.
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— The toxicity of arsenic spans across the tree of life, affecting microbes, plants, and animals (Jayasumana et al., 2015; Mandal and Suzuki, 2002; Molin et al., 2015; Podol'skaya et al., 2002) Arsenic contamination of soil and water in various parts of the world is an outcome of natural and/or anthropogenic sources such as mining, industrial ...
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— Soaking will be an alternative process to remove arsenic in brown rice. Abstract. One of the main food crops in the world, rice can accumulate high levels of arsenic from flooded paddy soils, which seriously threatens human health. Soaking, a common processing method for brown rice products, especially for brown rice noodles, was …
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— A hydrothermal upgrading process was developed for removal of heavy metals, including arsenic, lead, zinc and copper, and upgrading bio-oil from P. vittata and a heavy metals removal efficiency of >99% and crude bio-oil upgrading efficiency of 83.76% were attained under the determined conditions. The hydrothermal upgrading bio-oil …
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— Mineral deposits contain arsenic, combined with sulfur and metals such as cobalt, copper, gold and iron, from which it can be recovered as arsenic xide during …
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Arsenic is commonly found as an impurity in sulfide ores, and is produced commercially for use in pesticides, wood preservatives, metal alloys, and other technologies. It is also listed as critical mineral under Presidential executive order 13817, because it has important uses in our economy, …
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As described in the following sections of this chapter, it has been possible to demonstrate that methylation of As in many species is an enzymatically catalyzed process that is consistent with Challenger's original scheme for this process. A single protein, arsenic (+3 oxidation state) methyltransferase (AS3MT), catalyzes both reduction and ...
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— Arsenic speciation analysis on the collected samples showed that As associated with δ-MnO 2 was present as As(V) and no As(III) was observed in the effluent during the desorption phase (Lafferty et al ... Using a process-based modeling approach, this study evaluated a conceptual model that reflects the widely accepted mechanisms …
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— Batch pressure leach test work was conducted in 4 L autoclaves. Various compositions of feed solids, including both concentrates and/or the arsenic dust described above, and quench solutions (process water and acid plant effluent) were tested over a range of operating temperatures (200–230 °C) to select the conditions for pilot plant testing.
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arsenic xide into crystalline scorodite (FeAs0 4 • 2HzO) using acidic nitrate solu tions at temperatures ranging from 140°C to 160"C. A schematic process flow sheet is proposed. The reasons for processing arsenic xide, especially baghouse dust from met allurgical operations, lie in its toxic charac
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— Arsenic exposure through drinking water has established health impacts (), and although existing science supports the assumption that effects will be similar from food, the role of diet in population arsenic exposures has been less studied.Most epidemiologic studies describing arsenic's effects have relied on drinking water concentrations or urine …
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— Arsenic may be present in food from the environment where foods are grown, raised, or processed. ... processing, and manufacturing foods that contain lower levels of environmental contaminants ...
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— Arsenic-free acid (96% strength) was produced by the vanadium-catalyzed contact process due to the fact that arsenic-free starting materials had to be used because of poisoning of the catalyst by arsenic. There were many uses for the less-concentrated, and therefore cheaper, acid: two products in particular suffered from the presence of …
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— Several processing methods exist, as seen right, and in future higher arsenic volumes will likely be treated by a mixture of solutions, …
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— The aim of this study was to propose an intermediate processing stage (ii), between alkaline pretreatment (i) and gold leaching (iii), to remove the greatest amount …
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— The invention claimed is: 1. An arsenic removal method, comprising: a leaching step of leaching a non-ferrous smelting intermediate comprising a copper arsenic compound in the form of an intermetallic compound in the presence of monatomic sulfur, and obtaining a leaching solution comprising arsenic; a solution adjusting step of …
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Arsenic contaminations, often adversely influencing the living organisms, including plants, animals, and the microbial communities, are of grave apprehension. Many physical, chemical, and biological techniques are now being explored to minimize the adverse affects of arsenic toxicity. Bioremediation of arsenic species using arsenic loving bacteria has …
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— 1. Introduction. Arsenopyrite, the main arsenic-containing mineral, has emerged as the major source of environmental arsenic pollution. However, despite the ubiquity of arsenopyrite and the potential environmental impact and health hazards of arsenic on the environment, limit information is available regarding the stability and …
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— With new environmental legislation, demand arose for a simple and low-cost technology for arsenic waste processing into the disposable form. One of the cheapest methods consists of precipitation with lime. It has been proven however, that resulting solids are unstable when exposed to atmospheric carbon dioxide[1]. Another wide-spread and ...
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— Arsenic poisoning is a global health issue affecting millions of people worldwide through environmental and occupational exposure, as well as intentional suicide and homicide attempts. Although arsenic homicides commonly receive media publicity, the primary source of arsenic toxicity to the general population is by contaminated water, …
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