Water purification device for arsenic removal

A system, comprising:

• an inlet for an arsenic-containing aqueous feed, the aqueous feed comprising particulate solids;
• a liquid-solids separator to remove the particulate solids from the aqueous feed and form a liquid phase and solid phase, the liquid phase comprising the arsenic and the solid phase comprising the particulate solids;
• and
• an oxidation vessel comprising a cerium (IV) oxide to react with the arsenic to a higher oxidation state and a precipitating agent to form a precipitate with the arsenic in the higher oxidation state.

A system, comprising:

• an input for an aqueous feed contaminated with both arsenite comprising arsenic (III) and arsenate comprising arsenic (V) and a further contaminant that is at least one of selenium, cadmium, lead, mercury, and an organic contaminant;
• at least one of a bed, filter, and cartridge, the at least one of a bed, filter, and cartridge comprising cerium (IV) oxide and an arsenic precipitating agent to remove both the arsenite and arsenate from the aqueous feed, wherein the precipitating agent comprises a rare earth having a trivalent oxidation state;
• and
• a contaminant removal stage, positioned upstream of the at least one of a bed, filter, and cartridge, for removing the at least one of selenium, cadmium, lead, mercury, and an organic contaminant.

A device for removing arsenic from drinking water comprising:

• (a) an inlet communicating with a source of said drinking water having a first arsenic concentration comprising arsenite and arsenate;
• (b) a vessel containing a cerium-containing compound and a particulate arsenic precipitating agent, said cerium-containing compound comprises cerium dioxide (CeO2) having cerium in a +4 oxidation state, said cerium +4 reacts with said arsenite, said arsenite precipitating agent comprising a rare earth having a +3 oxidation state, and said particulate arsenic precipitating agent forms an insoluble arsenic compound with said arsenate, said cerium-containing compound and said particulate arsenic precipitating agent combined have greater than about 40 to about 45 cerium +4 calculated as an oxide, said vessel having an entry portion and an exit portion, wherein said entry portion communicates with the inlet;
• and
• (c) an outlet communicating with said exit portion of the vessel, wherein said drinking water leaves said vessel through said exit portion and wherein said drinking water exiting said exit portion has a second arsenic concentration less than said first arsenic concentration.

A device for removing arsenic from drinking water comprising:

• (a) an inlet communicating with a source of said drinking water having a first arsenic concentration comprising arsenite and arsenate;
• (b) a vessel containing a cerium-containing compound and a particulate arsenic precipitating agent, said cerium-containing compound comprising cerium dioxide (CeO2) having cerium in a +4 oxidation state, said cerium +4 reacts with said arsenite, and said particulate arsenic precipitating agent comprises a rare earth compound other than a cerium compound and forms an insoluble arsenic compound with said arsenate, said cerium-containing compound and said particulate arsenic precipitation agent combined having greater than about 40 to about 45cerium +4 calculated as an oxide, said vessel having an entry portion and an exit portion, wherein said entry portion communicates with the inlet;
• and
• (c) an outlet communicating with said exit portion of the vessel, wherein said drinking water leaves said vessel through said exit portion and wherein said drinking water exiting said exit portion has a second arsenic concentration less than said first arsenic concentration.

A system, comprising:

• an inlet for an aqueous feed comprising dissolved arsenic in the +3 and +5 oxidation states as arsenite and arsenate, respectively;
• at least one of a cerium-containing bed, filter, and cartridge to contact a mixture comprising cerium in the +4 oxidation state and lanthanum in the +3 oxidation state with the aqueous feed to remove the dissolved arsenic in the +3 and +5 oxidation states from the aqueous feed and form a treated aqueous feed;
• and
• an outlet for the treated aqueous feed.