84 results about "Reductive dechlorination" patented technology

The invention discloses a synthetic method of 1,1,1,4,4,4-hexafluoro-2-butene, and the synthetic method comprises the steps of carrying out a reaction between hexachlorobutadiene and hydrogen fluoride in the presence of a catalyst to generate 1,1,1,4,4,4-hexafluoro-2,3-dichlorobutane, and carrying out a reductive dechlorination reaction on the 1,1,1,4,4,4-hexafluoro-2,3-dichlorobutane in a solvent by using zinc powder to generate the 1,1,1,4,4,4-hexafluoro-2-butene. According to the synthetic method, the process is simple, the steps are short, the reaction conditions are mild and the product can be obtained through two steps of reaction; and the raw materials are easy to get, the cost is low, and the byproduct hexachlorobutadiene obtained by reducing tetrachloroethylene by carbon tetrachloride at high temperature can be used as a raw material, so that the cost is further reduced.

A method for treating contamination in subsurface formations includes fracturing the soil to produce a network of fractures in the formation and simultaneously injecting a slurry containing an optional proppant and a solid-phase or nonaqueous-phase treatment agent into the network of fractures. The proppant is for keeping the fractures open, and the treatment agent accelerates conversion of the contaminants into immobile or less toxic forms. Chitin is an illustrative solid-phase treatment agent, which functions as an electron donor for anaerobic reductive dechlorination mediated by dechlorinating bacteria.

In preferred embodiments, bioremediation systems are provided that comprise electricigenic microbes that use electrons provided directly from the anode of an electrical bioremediation system to carry out reductive dehalogenation of halogenated hydrocarbon contaminants, including chlorinated solvents. The present invention also provides methods of performing in situ bioremediation of halogenated solvents in groundwater or soil through the use of the provided systems.

A method for treating contamination in subsurface formations includes fracturing the soil to produce a network of fractures in the formation and simultaneously injecting a slurry containing an optional proppant and a solid-phase or nonaqueous-phase treatment agent into the network of fractures. The proppant is for keeping the fractures open, and the treatment agent accelerates conversion of the contaminants into immobile or less toxic forms. Chitin is an illustrative solid-phase treatment agent, which functions as an electron donor for anaerobic reductive dechlorination mediated by dechlorinating bacteria.

A stabilized, chemically reactive, metallic nano-material effective for degradation of chlorinated organic compounds in soils, sediments and groundwater. The nano-material is composed of a magnetic metal nanoparticle and a carbohydrate stabilizer bound to the nanoparticle. The preferred metal nanoparticle is iron and the preferred carbohydrate stabilizer is either a starch or a water soluble cellulose such as sodium carboxymethyl cellulose. The nanoparticle may be either mono-metallic, bi-metallic or multi-metallic in nature, but is preferably bi-metallic wherein it is coated with a secondary catalytic metal coating, preferably palladium. A method of making the metallic nano-material is further disclosed wherein a solution of the metal nanoparticle and carbohydrate stabilizer is prepared, and the nanoparticle is then reduced under inert conditions. A process for reductive dechlorination of chlorinated organic compounds is also disclosed wherein the reduced magnetic metal nanoparticle is prepared, and then contacted with a chlorinated organic compound to dechlorinate the compound. Preferably, the nano-material is injected into a site such as soil subsurface or groundwater contaminated with a chlorinated organic compound to provide in-situ dechlorination.

Compositions and methods for soil and groundwater remediation are contemplated as comprising a zero valent metal having a metal sulfide surface layer and an organic compound operative to degrade to produce molecular hydrogen. Such compositions may also include particulate activate carbon and anaerobic bacteria operative to perform reductive dechlorination. These compositions synergistically operate to remove chlorinated hydrocarbons from contaminated soil and groundwater.

This method of restricting methane production in methanogenic bacteria, by the use of the enzyme and coenzyme inhibitors, works during anaerobic reductive dechlorination. Various compounds such as, but not limited to, red yeast rice, vitamin B10 derivatives, and ethanesulfonates are utilized to disrupt these different enzyme and coenzyme systems responsible for the production of methane. This method affects the competition of the methanogen and halo bacteria for the organic hydrogen donors that are injected in the soil and groundwater system during the remediation process.

The invention relates to an in-situ purification technology which can be used for reductive dechlorination, heavy metal precipitation and microbial denitrification reaction. The in-situ purification technology requires an anaerobic reaction area used for precipitating and filtering soluble heavy metal, such as metal sulfide and nitrate which are converted to nitrogen, precipitates and filtered chromium. A pump process system is composed of one or more wells which extend to an underground pollution saturated zone. There are conduits in the wells, and the conduits are used for conveying carbohydrate and sulfate to the pollution saturated zone. In a reaction zone, dissolved state oxygen content is lower than 0.5mg / L, redox potential is lower than -250mv, and the ratio of soluble organic carbon compounds to pollutants is higher than 50:1. Meanwhile, microbes digest carbohydrate, sulfate can be reduced and methane can be generated. In this biogeochemical environment, PCE dechlorination can be caused for reduction to obtain TCE, TCE further undergoes dechlorination to generate DCE, dechlorination is carried out again to generate VE, and ethene is finally generated. Meanwhile, heavy metal precipitation and microbial denitrification reaction are also caused in the biogeochemical environment.

The invention discloses a biochar preparation for anaerobic reductive dechlorination of mediated polychlorinated biphenyls. The biochar preparation is prepared from the following components of, by weight, 1 L of an inorganic salt culture medium, 1.5-2.5 Ml of sodium lactate, 1-2 mL of a vitamin solution, 1-2 mg of an anaerobic microorganism, and 4-6 g of rape stem biochar. The biological preparation has the characteristics of being environment-friendly, non-toxic and the like, anaerobic reductive dechlorination of the polychlorinated biphenyls can be effectively mediated, and the biological preparation provides a new way for degrading of the polychlorinated biphenyls.