84 results about "Reductive dechlorination" patented technology

The invention discloses a method for in-situ bioremediation of pollution caused by chlorohydrocarbon of underwater, which specifically comprises a coupling process of anaerobic reductive dechlorination and aerobiotic oxydative degradation. An anaerobic reaction area and an aerobiotic reaction area are established in the front and back of a chlorohydrocarbon pollution area along the flowing direction of underwater in a zone of saturation. Poly-chlorohydrocarbon (trichloro or tetrachloro) in the anaerobic reaction area is quickly reduced and dechlorinated to low chlorohydrocarbon (monochloro or bichloro), the low chlorohydrocarbon is transferred to the aerobiotic reaction area and oxidized and degraded to products such as carbon dioxide. The anaerobic reaction area is realized by providing electron donor materials, a deoxidant and a reducer through the injection of an injection well, while the aerobiotic area is realized by aeration toward underground water.

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.

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.

The invention discloses a method for synthetizing 3,5-dichloroaniline by using industrial production residues, namely meta-position oil, of p-nitrchlorobenzene and ortho-nitrochlorobenzene by two steps of chlorination and reductive dechlorination. The method adopts the following technical scheme: adding an organic solvent to nitrochlorobenzene meta-position oil as a raw material, directly producing a quintozene mixture by one-step chlorination under the effect of a catalyst, reacting for 0.5-10 hours under the condition of 10-180 DEG C, and then cooling to 30 DEG C; filtering out quintozene, and putting into an autoclave after washing into a neutral state by hot water; carrying out dechlorination reduction reaction under the effects of an organic solvent and the catalyst, wherein the reaction temperature is 60-200 DEG C, the reaction pressure is 1-20 MPa, and the reaction time is 1-20 hours; cooling to room temperature after the reaction is ended; leading in oxygen or air to stir after blowing off; filtering and distilling under reduced pressure to remove the solvent, so as to obtain the product 3,5-dichloroaniline, wherein the yield is 80-90%. Waste materials are changed into precious materials by a synthetic route adopted by the technology disclosed by the invention; the target of zero emission is achieved; the method has the advantages of sustainable development, energy conservation and consumption reduction, and small environmental pollution.

The present invention relates to an assay for identification of PCB dechlorinating organisms that are capable of biologically removing PCBs from contaminated materials. Specifically, the invention provides a set of primers for detecting PCB dechlorinating organisms in a sample. These individual primers of the primer set have a sequence of at least 12 nucleotides that is unique to 16S rDNA of PCB dechlorinating organisms.

The invention discloses anaerobic granular sludge capable of reinforcing dechlorination performance and a preparation method and an application of the anaerobic granular sludge. The anaerobic granular sludge capable of reinforcing the dechlorination performance comprises zero-valent iron and anaerobic sludge, wherein the anaerobic sludge is attached to the outer surface of the zero-valent iron and contains microbial thallus; and the anaerobic granular sludge capable of reinforcing the dechlorination performance can be applied to degradation of wastewater containing chlorinated hydrocarbon. The anaerobic granular sludge has the advantages of good settling property, stable granules, compact structure and efficient and stable reductive dechlorination activity; according to the granular sludge, functional flora such as reductive dechlorinating bacteria are effectively enriched; space obstacles in transferring of metabolic fluxes such as electron donors [H] and intermediate products are removed; and the reductive dechlorination performance of a UASB (upflow anaerobic sludge blanket) reactor is reinforced.

The invention relates to the technology of preparation of catalytic materials, and aims to provide a preparation method of a Cu/Pd alloy modified TiO2 catalyst for reductive dechlorination materials. The method comprises the following steps: preparing a nano-sheet-like TiO2 catalyst by using tetrabutyl titanate as a titanium precursor and utilizing corrosion performance of HF(hydrogen fluoride) through hydrothermal reaction; preparing a Cu/Pd alloy co-modified TiO2 catalyst through an immersion-reducing atmosphere calcination method. Complex Cu and Pd salt solutions and the catalyst are mixed and immersed, and after vacuum drying, calcination under a hydrogen reducing atmosphere is carried out. According to the preparation method disclosed by the invention, visible light response of the catalyst is realized, and high-efficient reductive hydrogenation dechlorination in aqueous solutions under visible light can be carried out by utilizing a synergistic effect of Cu/Pd alloys, and a catalytic dechlorination effect of the catalyst is superior to that of a commercialized P25/Pd individually-loaded TiO2 catalyst. By the formation of the Cu/Pd alloys, the catalyst has the advantages that the using amount of precious metals is reduced while the good dechlorination effect is achieved, and practical application of reductive dechlorination under visible light is facilitated.

The invention relates to a PVDF (Polyvinylidene Fluoride)/Fe-Pd bi-metal nanoparticle hybrid membrane and a preparation method thereof. The preparation method comprises the steps of blending polymer microspheres and PVDF to prepare a membrane, and then, loading ferrum-palladium bi-metal nanoparticles to prepare the hybrid membrane with favorable catalytic reaction activity and separation performance. By using the PVDF/Fe-Pd bi-metal nanoparticle hybrid membrane, chlorine-contained organisms such as trichloro ethylene, monochloroacetic acid, dichlorinated biphenyl, dichlorphenoxyacetic acid and the like can be subjected to reductive dechlorination reaction, and chlorine atoms in the chlorine-contained organisms are converted into hydrogen atoms. In addition, the membrane can also be used for the catalytic reduction reaction of nitro in nitrobenzene molecules such as aminonitrobenzene, nitrobenzene, methylnitrobenzene and the like so as to convert the nitro into an amino group.

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.

The invention discloses a new application of caragana microphylla charcoal and a mediate chlorophenasic acid anaerobic reductive dechlorination process thereof. The caragana microphylla charcoal serves as a solid electronic medium for mediate chlorophenasic acid anaerobic reductive dechlorination. The caragana microphylla charcoal serves as the solid electronic medium, so that biological anaerobic reductive dechlorination of chlorophenasic acid is promoted; and the caragana microphylla charcoal is naturally made, is environment-friendly and widely exists in the natural environment.

The invention discloses a screening separation method of a bacterial strain for degradation of 2,4,6-trichlorophenol, and relates to the technical field of treatment of organic pollutants. The method comprises the steps: collecting activated sludge in a papermaking wastewater inner circulation anaerobic reactor, carrying out enrichment acclimation in a strictly anaerobic environment, then inoculating solid screening culture mediums having addition of 2,4,6-trichlorophenol respectively with the acclimated sludge according to the dilution gradient, and separating to obtain various purified bacterial strains having the ability to degrade 2,4,6-trichlorophenol; and finally, respectively inoculating degradation culture mediums having addition of 2,4,6-trichlorophenol with the various purified bacterial strains, and screening to obtain the bacterial strain having the highest degradation efficiency on 2,4,6-trichlorophenol. The method is simple, and the obtained spindle-shaped lysine bacillus has relatively high purity and high yield. The invention also provides the bacterial strain for degradation of 2,4,6-trichlorophenol; the bacterial strain can degrade chlorophenol organic matters through reductive dechlorination under anaerobic conditions, and has good degradation effect.

The invention relates to a combination degradation technology, and particularly relates to a process for combination degradation of polychlorinated biphenyls. According to the process, polychlorinated biphenyls in an organic-aqueous system are subjected to reductive dechlorination reaction for 1.5-4h by adding an alkaline proton absorbent under the catalysis of transition metals with hydrogen gas as the gas source, and subsequently the reaction solution of the reductive dechlorination reaction is added into a carbon-free culture medium for cultivation of candida tropicalis to result in full degradation of the polychlorinated biphenyls. The process has the advantages that the catalysis reduction efficiency of polychlorinated biphenyls is high, and the reaction conditions are simple and modest; the reactants are thoroughly degraded; the operation is easily controlled and the cost is low; and the process is economic and environment-friendly.

The invention relates to a method for carrying out intensified reductive dechlorination on triclosan in sewage by using vitamin B12. According to the method, nano zero-valent iron and vitamin B12 are added to sewage containing triclosan under the condition that the pH value is 5-9, the reaction time is 5-10 hours, so that sewage is subjected to intensified reductive dechlorination, wherein the mass concentration of triclosan in sewage is 1-20mg/L; 0.1-1g of nano zero-valent iron is added to each liter of sewage; and 10-100mg of vitamin B12 is added to each liter of sewage. Compared with the prior art, the method disclosed by the invention is simple in reaction condition, mild in reaction, short in treatment time, high in triclosan removal rate, free of secondary pollution, suitable for treatment of sewage containing triclosan and other pharmaceutical wastewaters, and beneficial to resource utilization of the sewage.

The invention discloses a separation method of an efficient chlorophenol degrading bacterial strain, and the efficient chlorophenol degrading bacterial strain Pseudomonassp.TB-1, with the collection number of CGMCCNo.9686. obtained through the separation method. The separation method comprises the following steps: obtaining anaerobic activated sludge from an internal-circulating anaerobic papermaking wastewater treatment reactor, domesticating and screening for a long time, and separating to obtain a bacterial strain for efficiently degrading 2, 4, 6-trichlorophenol through reductive dechlorination. The bacterial strain can completely degrade the 2, 4, 6-trichlorophenol with a concentration of 30mg/ L within 72 hours, and still has a degrading rate of 72% when the concentration of the 2, 4, 6-trichlorophenol (2, 4, 6-TCP) is as high as 150mg/ L.

A prediction and assessment tool for bioremediation performance based on a comprehensive understanding of the link between chemical flow and microbial community interactions includes linking molecular microbial ecology data with electron and alkalinity balances to make it possible to understand dechlorinating microbial communities and their metabolic processes. The interactions of biological processes and site mineralogy result in changes to alkalinity and pH that can lead to incomplete reductive dechlorination resulting from suboptimal pH. Understanding these interactions allows for strategies to predict expected bioremediation outcomes and/or to mitigate incomplete reductive dechlorination.

Anaerobic reductive dechlorination processes remove chlorinated solvents from contaminated subsurface soil and ground water. The presence of organic hydrogen donors enables anaerobic microorganisms present in the subsurface soil and groundwater to accelerate the reductive dechlorination process. The present invention provides an alternative method to control the release rate of organic hydrogen donors during dechlorination. The invention utilizes encapsulated substrates to control the release rate of organic hydrogen donors, therefore accelerating the biotic process of anaerobic reductive dechlorination.

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.