A method of chromium removal from wastewater comprising providing a copper augmented biochar and contacting the copper augmented biochar with the wastewater to remove chromium from the wastewater. The copper augmented biochar can remove chromium from wastewater with about 99% efficiency in about 1 hour.

The present invention relates to a method for removing hexavalent chromium from water bodies by sodium oxalate-modified zero-valent iron. The method comprising the steps: soaking zero-valent iron in a sodium oxalate solution for a period of time; and washing and drying to obtain the sodium oxalate-modified zero-valent iron; and then treating water bodies with the sodium oxalate-modified zero-valent iron to remove the heavy metal pollutant hexavalent chromium from the water bodies. Compared with other chemical or physical methods for treating the zero-valent iron, the processing technology of the sodium oxalate-modified zero-valent iron is simple and easy to implement, and also has advantages of high efficiency, no pollution and environmental friendliness.

The present invention relates to a method for removing hexavalent chromium from water bodies by sodium oxalate-modified zero-valent iron. The method comprising the steps: soaking zero-valent iron in a sodium oxalate solution for a period of time; and washing and drying to obtain the sodium oxalate-modified zero-valent iron; and then treating water bodies with the sodium oxalate-modified zero-valent iron to remove the heavy metal pollutant hexavalent chromium from the water bodies. Compared with other chemical or physical methods for treating the zero-valent iron, the processing technology of the sodium oxalate-modified zero-valent iron is simple and easy to implement, and also has advantages of high efficiency, no pollution and environmental friendliness.

The present application discloses a method of binding a metal ion in water. The method comprises contacting the water with a fraction of dissolved organic material (DOM) to form a complex between the DOM fraction and the metal ion; and optionally separating the complex from the water. The present application also discloses a use of DOM for binding a metal ion in water.

The present application discloses a method of binding a metal ion in water. The method comprises contacting the water with a fraction of dissolved organic material (DOM) to form a complex between the DOM fraction and the metal ion; and optionally separating the complex from the water. The present application also discloses a use of DOM for binding a metal ion in water.

A method for immobilizing arsenic includes adding calcium arsenate to a glass-forming material containing iron, silica, and alkaline components so that an iron/silica weight ratio is in a range of 0.5 to 0.9 and an amount of alkaline components is in a range of 14 wt % to 26 wt %, and thereby incorporating the arsenic into a glass solidified body. For example, the method for immobilizing arsenic may include: adding an alkaline solution and an oxidizing agent to a copper-arsenic-containing substance, and thereby carrying out an oxidizing leaching; separating a leach residue by solid-liquid separation; adding calcium hydroxide to a recovered alkaline arsenate solution to generate calcium arsenate; and adding the glass-forming material to the recovered calcium arsenate so that the iron/silica weight ratio and the amount of alkaline components are in the above-mentioned ranges, and thereby incorporating the arsenic into the glass solidified body.

A method for immobilizing arsenic includes adding calcium arsenate to a glass-forming material containing iron, silica, and alkaline components so that an iron/silica weight ratio is in a range of 0.5 to 0.9 and an amount of alkaline components is in a range of 14 wt % to 26 wt %, and thereby incorporating the arsenic into a glass solidified body. For example, the method for immobilizing arsenic may include: adding an alkaline solution and an oxidizing agent to a copper-arsenic-containing substance, and thereby carrying out an oxidizing leaching; separating a leach residue by solid-liquid separation; adding calcium hydroxide to a recovered alkaline arsenate solution to generate calcium arsenate; and adding the glass-forming material to the recovered calcium arsenate so that the iron/silica weight ratio and the amount of alkaline components are in the above-mentioned ranges, and thereby incorporating the arsenic into the glass solidified body.

Provided herein are methods for removing mercury contaminant from an aqueous solution, the methods including: providing an aqueous solution, the aqueous solution being contaminated with at least trace amounts of an oxidized mercury species; culturing a photoheterotrophic or fermentative heterotrophic bacteria in the aqueous solution under anaerobic conditions in which the bacteria reduce the oxidized mercury species to elemental mercury (Hg.sup.0), wherein the bacteria comprises one or more bacteria of the order Clostridiales; and removing the elemental mercury from the aqueous solution. Also provided are bioreactors for removing mercury contaminant from an aqueous solution, as well as uses of photoheterotrophic or fermentative heterotrophic bacteria, wherein the bacteria comprises one or more bacteria of the order Clostridiales, for removing mercury contaminant from an aqueous solution.

Provided herein are methods for removing mercury contaminant from an aqueous solution, the methods including: providing an aqueous solution, the aqueous solution being contaminated with at least trace amounts of an oxidized mercury species; culturing a photoheterotrophic or fermentative heterotrophic bacteria in the aqueous solution under anaerobic conditions in which the bacteria reduce the oxidized mercury species to elemental mercury (Hg.sup.0), wherein the bacteria comprises one or more bacteria of the order Clostridiales; and removing the elemental mercury from the aqueous solution. Also provided are bioreactors for removing mercury contaminant from an aqueous solution, as well as uses of photoheterotrophic or fermentative heterotrophic bacteria, wherein the bacteria comprises one or more bacteria of the order Clostridiales, for removing mercury contaminant from an aqueous solution.

The present invention reduces adhesion of trace metals in ultrapure water for cleaning products, and inhibits the metal contamination of an object to be cleaned. Provided is a metal contamination inhibitor that contains a polymer having an ion-exchange group, such as a polystyrene sulfonate having a molecular weight of at least 100,000. Trace metals in ultrapure water are adsorbed through an ion-exchange reaction of the polymer having the ion-exchange group, and can thus be inhibited from adhering to products. Also provided is a method for cleaning a product with ultrapure water to which the metal contamination inhibitor has been added. Preferably, the ultrapure water to which the metal contamination inhibitor has been added flows through a separation membrane module, and the products are cleaned with permeated water.