This document describes industry-specific approaches to prevention, control and removal of selenium in water, with a focus on water treatment approaches for selenium removal. Industries represented in the North American Metals Council - Selenium Work Group (NAMC-SWG) are faced with managing selenium in water from processes that include the
removal selenium alumina
Adsorption of selenite (SeO) and selenate (SeO) on hydrous alumina (γ-Al 2 O 3) was studied using batch equilibrium experiments. pH, the single most significant parameter, affected both speciations of selenium (Se) and of surface hydroxo groups on alumina that, in turn, determined the extent of adsorption of the oxyanions. Adsorption of both ...
Laboratory studies were performed to determine optimum conditions for using activated alumina to remove selenium from drinking water supplies. Column tests showed that the capacity of alumina for Se IV decreased as influent pH increased. Best removal of Se IV occurred at pH 5 where 1200 bed volumes of water, with influent concentration of 0.2 ...
Activated Alumina is comprised of a synthetically-produced aluminum oxide (A1 2 O 3) in a smooth spherical form with high-crush strength.It is highly porous and can have a high surface area greater than 300 m 2 /g. It is an excellent desiccant for liquids and gases, and can achieve dew points from -40°F (-40°C) depending on the operating conditions and the design of the dryer.
The data also showed that y alumina provided higher selenium removal percentages (99%) compared to α alumina (94%), activated carbon (87%) and chitin (49%). The selenite removal was found to decrease with increasing initial Se (IV) concentration in the solution.
Removal of Selenium from Aqueous Solutions Using Magnetite Nanoparticles a s Adsorbent . ... Selenium (Se) is problematic contaminant for many a regions worldwide. Adsorption is by far the most ... adsorbents have been tested for Se removal, such as alumina, …
Other techniques used for selenium removal include distillation (> 98% reduction), reverse osmosis (RO) (> 90% reduction), and activated alumina (AA) (85-95% reduction). Several point-of-use (POU) RO and POU distillation products have been tested and certified by ANSI-accredited third party organizations for selenium reduction.
Selenium (Se) is encountered in surface and groundwaters in the United States at concentrations that rarely exceed the drinking water standards (0.01 mg/L). However, in the western United States, leachates from heap-leaching operations at gold mines may contain selenium concentrations as high as 2 mg/L. In the gold heap leaching process, a solution containing sodium cyanide is sprinkled on the ...
Activated alumina was investigated as a selenium removal technique in earlier studies sponsored by EPA, but its removal efficiency depends on the selenium species present. Alumina effectively removed selenium in the +IV valence state (selenite) but not in the +VI valence state (selenate).
A process for removing selenium and/or arsenic from aqueous streams including industrial process waters and drinking water is provided comprising contacting the stream with a composition comprising lanthanum oxide whereby selenium and/or arsenic are adsorbed. Preferred compositions comprise lanthanum oxide and alumina.
Highlights This article demonstrates fast removal of selenium from water by adsorption at affordable pH level. Removal is done according to water quality restrictions. Complete recovery of the adsorbent for reuse was shown, followed by contaminant removal as solid barium selenate. Relatively high adsorption of the selenium ions, at the permitted concentration level was demonstrated, in ...
Figure 9 shows the relationship of selenium removal versus activated alumina contact time with a one percent solution of sodium hydroxide (1% NaOH). Fresh activated alumina was rinsed with this basic solution for various amounts of time to test the effect of NaOH rinse time on capacity for selenium removal.
Selenium has antioxidant properties and may help protect cells from damage. Most people get enough of this essential mineral from foods, and taking too much may lead to health problems. WebMD ...
The study revealed that 68% of the selenium in the leachate could be removed by alumina at pH levels greater than 5.0. At pH levels less than 4, silica was poorly adsorbed by alumina, and selenium adsorption was improved. Silica adversely affected the selenium adsorption capacity.
Jan 15, 2016· Selenium Removal Technologies: A Review. ... Activated alumina has been used for selenium removal by Pureflow Filtration and others. An adsorptive activated alumina media and associated chemical treatment system provides an automated, low-maintenance treatment system. However, this process requires selenium to be in the selenite form.
The use of activated alumina for the removal of selenium from heap leach detoxification solutions was studied at a laboratory scale. Three aluminas were studied: one unmodified and two chemically modified to function better in a basic pH range. The best performer, Discovery Chemicals DD-6, readily accumulated selenium oxyanions.
selenium. The bed is then flushed with raw water to remove excess caustic solution and neutralize the bed. Automatic pH control insures optimum chemical pretreatment. Selenium ions are attracted and held to the vast surface areas throughout the pores of the activated alumina, and selenium removal is reliably achieved.
The use of activated alumina for the removal of selenium from heap leach detoxification solutions was studied at a laboratory scale. Three aluminas were studied: one unmodified and two chemically ...
Activated alumina is manufactured from aluminium hydroxide by dehydroxylating it in a way that produces a highly porous material; this material can have a surface area significantly over 200 m²/g. The compound is used as a desiccant (to keep things dry by absorbing water from the air) and as a filter of fluoride, arsenic and selenium in drinking water. ...
Other techniques used for selenium removal include distillation (> 98% reduction), reverse osmosis (RO) (> 90% reduction), and activated alumina (85-95% reduction). Several point-of-use (POU) RO and POU distillation products have been tested and certified by ANSI-accredited third party organizations for selenium reduction.
removal, which is one of the predominant selenium species in the agricultural drainage water. The data also showed that γ alumina provided higher selenite removal percentages (99%) as compared to α alumina (94%), activated carbon (87%) and chitin (49%).
selenium in water to less than 5 µg/L at any scale. Still fewer technologies have been demonstrated at full-scale to remove selenium to less than 5 µg/L, or have been in full-scale operation for sufficient time to determine the long-term feasibility of the selenium removal technology.
Selenium Removal With Activated Alumina THE PUREFLOW© SYSTEM FOR THE REMOVAL OF SELENIUM from drinking water supplies is an improved design for the water treatment industry. A highly adsorptive activated alumina media, and chemical treatment system, combine to provide a simple, safe, compact process, with automatic controls ...
Control options for addressing selenium in drinking water include blending of waters, selection of alternative low-selenium sources and the removal of excess selenium by treatment processes at the public water supply or level.
ContentsLoading to the Alumina to the AdsorbersBackwashing the Fixed Bed AdsorbersSelenium and Silica Adsorption CapacityEmpty Bed Contact Time (EBCT)Alumina RegenerationRegenerant Solution Disposal One objective of this study was to determine the critical parameters needed for designing of a plant to remove selenium from the mine leachate.
Additional Physical Format: Online version: Trussell, R. Rhodes. Selenium removal from ground water using activated alumina. Cincinnati : Municipal Environmental Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency ; Springfield, Va. : Available to the public through the National Technical Information Service, 1980
The performance of selenium remediation agents, mainly gamma alumina sorbents and zerovalent metals is greatly inhibited in the presence of large concentrations of sulfate found in selenium-rich agricultural drainage water. It is therefore imperative to remove sulfates from these contaminated waters, prior to their treatment for selenium removal.
Example 1. Removal of Selenium with Commercial Alumina. The removal of selenium as a function of time with commercial grade DD-6™, Discovery Chemical (Port Allen, LA), (alumina catalyst) is given in Figures 1, 2 and 3. As can be seen, after four hours, 20-40 percent of initial selenium …
Removal of selenite from aqueous phase using iron-coated granular activated carbons (GAC) was investigated in this study. Five different types of GAC were used for iron coating by oxidizing ferrous chloride with sodium hypochlorite and the
Selenium is a metal found in natural deposits as ores containing other elements. The greatest use of selenium compounds is in electronic and photocopier components, but they are also widely used in glass, pigments, rubber, metal alloys, textiles, petroleum, medical …
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