Selenium compounds present in aqueous liquids containing sulfate and or chloride anions can be effectively removed by passing the liquid through a thiouronium modified anion ion exchange resin.
A process for removing contaminating levels of selenium from a contaminated aqueous solution is disclosed. That process includes providing a vessel or flow-permissive container containing a water-insoluble polymeric adsorption medium having a plurality of polymerized C.sub.1 -C.sub.4 N-alkylated pyridinium-containing adsorption sites. An influent of an aqueous solution having a total selenium concentration of about 10 to about 1000 parts per billion is introduced to the vessel or flow-permissive container to contact the insoluble polymeric adsorption medium. The solution is maintained in contact with that insoluble adsorption medium for a time period sufficient for the medium to bind the selenium in the contacting solution. The resulting aqueous solution is discharged from the vessel as an effluent having a total selenium concentration whose ratio to the total selenium concentration of the influent is about zero to about 10.sup.-3.
The present invention is directed to a method for removing selenium from a waste stream. The process is a multi-step process that removes selenium from a waste stream in the form of barium selenate and/or barium selenite. In a further step, the barium selenate and/or barium selenite forms a complex precipitate with barium sulfate, which encapsulates the barium selenate and/or barium selenite. The complex precipitate is subsequently removed from the waste stream.
A process for removing selenium from an aqueous stream using a supported sulfur material, to convert selenocyanate to selenite, followed by removal of the selenite from the aqueous stream.
A process for removing selenium from an aqueous stream using a supported sulfur material, and optionally the addition of an activating agent for enhanced removal of selenite, is disclosed.
The present invention provides a process for removing arsenic from ground water to be processed and used in remote dwellings. The process includes (a) contacting a clay, a coagulant, and an oxidizer with water containing arsenic to form a coagulated colloidal mixture; (b) adsorbing the arsenic onto the coagulated colloidal mixture; and (c) separating the water from the coagulated colloidal mixture. The invention also provides a composition ready for use in removing arsenic from ground water to be used in remote areas. The composition includes an activated clay, a coagulant, and an oxidizer in predetermined proportions for efficient removal of arsenic from ground water.
