291 results about "Arsenate" patented technology

A nanoparticle including an inorganic core comprising at least one metal and/or at least one semi-conductor compound comprising at least one metal includes a coating or shell disposed over at least a portion of a surface of the core. The coating can include one or more layers. Each layer of the coating can comprise a metal and/or at least one semiconductor compound. The nanoparticle further includes a ligand attached to a surface of the coating. The ligand is represented by the formula: X-Sp-Z, wherein X represents, e.g., a primary amine group, a secondary amine group, a urea, a thiourea, an imidizole group, an amide group, a phosphonic or arsonic acid group, a phosphinic or arsinic acid group, a phosphate or arsenate group, a phosphine or arsine oxide group; Sp represents a spacer group, such as a group capable of allowing a transfer of charge or an insulating group; and Z represents: (i) reactive group capable of communicating specific chemical properties to the nanocrystal as well as provide specific chemical reactivity to the surface of the nanocrystal, and/or (ii) a group that is cyclic, halogenated, or polar a-protic. In certain embodiments, at least two chemically distinct ligands are attached to an surface of the coating, wherein the at least two ligands (I and II) are represented by the formula: X-Sp-Z. In ligand (I) X represents a phosphonic, phosphinic, or phosphategroup and in ligand (II) X represents a primary or secondary amine, or an imidizole, or an amide; In both ligands (I) and (II) Sp, which can be the same or different in the two compounds, represents a spacer group, such as a group capable of allowing a transfer of charge or an insulating group; Z, which can be the same or different in the two compounds, is a group chosen from among groups capable of communicating specific chemical properties to the nanoparticle as well as provide specific chemical reactivity to the surface of the nanoparticle. In preferred embodiments, the nanoparticle includes a core comprising a semiconductor material.

A method for preparing highly stabilized and dispersible zero valent iron nanoparticles and using the nanoparticles as a remediation technology against inorganic chemical toxins in contaminated sites. The method employs a composition containing select polysaccharides (starch or cellulose) as a stabilizer for the iron nanoparticles in a liquid carrier, and results in suspensions of iron nanoparticles of desired size and mobility in water, brine, soils or sediments. The stabilizer facilitates controlling the dispersibility of the iron nanoparticles in the liquid carrier. An effective amount of the composition is delivered to a contaminated site so that the zero valent iron nanoparticles can remediate one or more toxins such as an arsenate, a nitrate, a chromate, or a perchlorate in the contaminated site.

A method for removing arsenic species from an aqueous medium with modified zeolite minerals comprising providing an aqueous medium containing arsenic species in the form of both arsenate and arsenite, contacting the aqueous medium with an iron (II) laden zeolite mineral so that arsenic in the form of at least one of arsenate and arsenite contained in the aqueous medium can be adsorbed onto the iron (II) laden zeolite mineral forming an arsenic adsorbed iron (II) laden zeolite mineral, and separating the arsenic adsorbed iron (II) laden zeolite mineral from the aqueous medium.

The invention provides a soot treatment process in a copper smelting process. The soot treatment process comprises the following steps: firstly carrying out water leaching on copper smelting soot to obtain a water leaching fluid and water leaching residues; then, carrying out acid leaching on one part of the water leaching residues obtained in the last step to obtain an acid leaching fluid, and carrying out alkali leaching on the other part of the water leaching residues to obtain an alkali leaching fluid; carrying out metal replacement on the acid leaching fluid obtained in the last step to precipitate copper to obtain copper-precipitated filtrate; and finally, neutralizing and oxidizing the copper-precipitated filtrate obtained in the last step and the alkali leaching fluid obtained in the last step to obtain ferric arsenate precipitates and arsenic-precipitated filtrate. The soot treatment process provided by the invention, especially the treatment process for high-arsenic high-copper soot realizes the hazard-free treatment effect of arsenic in the high-arsenic high-copper soot, and comprehensively recycles valuable metal copper, zinc and the like in the high-arsenic high-copper soot, so that gradient recycling and comprehensive utilization of soot impurities are realized.

The invention discloses a method for remedying arsenic polluted soil. The method comprises a step of adding iron salt solution into the arsenic polluted soil so that the iron salt solution is reacted with arsenic in the soil to form arsenate FeAsO3 or FeAsO4 of iron. Before the iron salt solution is added, the method also comprises a step of crushing the arsenic polluted soil and steps of adjusting the pH of the arsenic polluted soil and measuring the arsenic content of the arsenic polluted soil. The method can quickly and efficiently treat the arsenic polluted soil, has simple operation and management and is suitable for major unexpected arsenic pollution remediation.

A method for removing arsenic from water by contacting water with a strong base anion exchange resin comprising at least one metal ion or metal-containing ion whose arsenate salt has a K_sp no greater than 10⁻⁵, provided that the metal is not zirconium.

The invention relates to a method for treating arsenic-containing wastewater by a process of preoxidation-composite coagulation deposition-filtering, and belongs to the technical field of wastewater treatment. The method comprises the steps of adding a certain amount of an oxidizing agent in a reaction tank for preoxidation in a condition that the wastewater contains trivalent arsenic so as to transform the trivalent arsenic into pentavalent arsenic completely, while for the wastewater only contains the pentavalent arsenic, the preoxidation process is not needed; adding a certain amount of a ferrous salt water solution; controlling a molar ration of Fe to As being 5-50; adding acid or alkali to adjust a pH value being 6-8; stirring for 0.1-1 min rapidly, so that a ferric arsenate precipitate is formed, at the same time, the ferrous salt is hydrolyzed into ferrous carbonyl to promote coagulation deposition of the ferric arsenate; adding a solution of 0.1-10 mg/L organic polymer flocculant; stirring for 0.1-1 min rapidly; stirring for 5-10 min slowly, precipitating for 10-30 min, discharging sludge from the bottom, introducing supernatant into a sand filter tank, a filter film or a filter bag, filtering and discharging the effluent. Arsenic content in water after treatment is lower than that of a drinking water standard (less than 10 [mu]g/L) regulated by the world health organization. The method has low sludge production and low cost, and can be used for advanced treatment of the arsenic-containing industrial wastewater and treatment of arsenic polluted underground water and drinking water.

A surface-enhanced Raman spectroscopy (SERS) substrate formed from a plurality of monolayers of polyhedral silver nanocrystals, wherein at least one of the monolayers has polyvinypyrrolidone (PVP) on its surface, and thereby configured for sensing arsenic is described. Highly active SERS substrates are formed by assembling high density monolayers of differently shaped silver nanocrystals onto a solid support. SERS detection is performed directly on this substrate by placing a droplet of the analyte solution onto the nanocrystal monolayer. Adsorbed polymer, polyvinypyrrolidone (PVP), on the surface of the nanoparticles facilitates the binding of both arsenate and arsenite near the silver surface, allowing for highly accurate and sensitive detection capabilities.

A method for removing dissolved contaminants from solution using a surface-activated crystalline titanium oxide product having a high adsorptive capacity and a high rate of adsorption with respect to dissolved contaminants, in particular, arsenate and arsenite. Preferably, the titanium oxide product includes crystalline anatase having primary crystallite diameters in the range of 1-30 nm. The surface-activated titanium oxide is combined with other filter media to further improve the removal of dissolved contaminants.

The invention consists of a water treatment process using selective and regenerable weak base anion exchange resins to remove any number of complex anions, especially oxyanions including perchlorate, nitrate, chlorate, arsenate, selenate, and chromate, from aqueous solutions. The treatment process is comprised of three key processes including 1) pretreatment to lower pH, 2) ion exchange, and 3) post treatment to adjust pH and alkalinity. The invention also includes processes for regenerating weak base anion resins and treatment of the residuals generated. This invention employs pressurized treatment, carbon dioxide management, and reuse of regenerating solution to minimize pumping and treatment costs.

The invention relates to a determination method for inorganic arsenic in aquatic products. After being extracted by hydrochloric acid solution, the inorganic arsenic (1plus1) in the aquatic products passes through an anion-exchange column, and arsenite As (III), dimethyl arsenic compound DMA, methyl arsenic compound MMA and arsenate As (V) are eluted sequentially by mobile phase; owing to different adsorption capacities of the anion-exchange column on the arsenate As (V), the arsenite As (III), the methyl arsenic compound MMA, the dimethyl arsenic compound DMA and arsenic sugar AsS, the eluted solution is hydrogenated by borohydride potassium reducing agent and hydrochloride, and hydride is generated, enters an atomizer, and is subject to analytic determination by being combined with atomic fluorescence. The experimental condition is reasonably selected, and the detecting data is accurate and reliable and can not be influenced by extraction time and temperature. The determination method of inorganic arsenic in aquatic products of the invention not only can detect the inorganic arsenic iAs accurately, but also can determine the methyl arsenic compound MMA and the dimethyl arsenic compound DMA of the organic arsenic, and can be used for the morphometry of the arsenic in the aquatic products.

The invention provides a method for treating arsenic-containing waste copper slag. The method comprises the following steps of: adding alkali and arsenic fixation roasting on the arsenic-containing waste copper slag from a copper electrolysis purification procedure to convert the arsenic into low-toxicity, water-soluble and nonvolatile arsenate, leaching the roasting slag into water to remove the arsenic, recovering copper and enriching antimony bismuth silver by virtue of acid leaching, and embedding calcium arsenate sediment converted from the arsenic in the water leaching solution; and comprehensively recovering valued metals such as copper, silver, antimony and bismuth in the black copper slag. The method is a safe and effective wet smelting method for recovering the valued metals in the black copper slag, and the arsenic and the copper are leached separately; the recovery rate of the copper in the black copper slag reaches 99.6 percent, and the removal rate of the arsenic reaches over 98 percent; over 95 percent of antimony and over 98 percent of bismuth enter the slag, and over 98 percent of silver also enters the acid leaching slag by adding trace chlorine radicals during acid leaching, so that the antimony, the bismuth and the silver are comprehensively recovered; and the method has the advantages of low equipment investment, short flow, low running cost and safe and reliable operating environment.

The invention discloses a method for preparing arsenic by direct reduction and roasting of an arsenic-containing material. The method comprises the following steps: taking arsenate as a raw material, uniformly mixing the arsenate material with a carbonaceous reducing agent to obtain a mixture, putting the mixture into an inert or reducing atmosphere, carrying out reduction and roasting under a negative pressure condition, and collecting roasting flue gas to obtain an arsenic product. According to the method, the arsenic-containing material which is commonly used in a metallurgical process and takes the arsenate as a main component is reduced into chemically stable elementary arsenic; the elementary arsenic is nontoxic, can be used as a raw material in the semiconductor and alloy industries, and has a certain market value; weight reduction, harmlessness and recycling of the toxic arsenic-containing material are realized in the reduction process and are the most reasonable development direction of arsenic; and therefore, the method has a large popularization value.

The invention relates to a non-ferrous metal smelting high-arsenic contaminated acid arsenic fixing process which sequentially includes the steps: pre-neutralization, to be specific, mixing iron-containing slag or iron-containing reagents and smelting contaminated acid, controlling Fe/As molar mole ratio, throwing mixed slurry and the contaminated acid into a pre-neutralization tank, performing reaction, controlling the pH (potential of hydrogen) value of solution, thickening pre-neutralization slag slurry to obtain bottom flow, supernate and gypsum slag, and using the gypsum slag as a cementretarder for sales; oxidation, to be specific, supplementing iron sulfate serving as an iron source reagent as required, heating the pre-neutralized supernate, adding hydrogen peroxide serving as an oxidizing agent for oxidation, controlling oxidation-reduction potential, and completely oxidizing trivalent arsenic into pentavalent arsenic; crystal form iron arsenate precipitation arsenic fixing, to be specific, controlling reaction temperature, adding seed crystals, controlling reaction endpoint pH values by adding lime milk, and conveying bottom flow subjected to two-stage arsenic precipitating reaction to a landfill through filter-pressed crystal form iron arsenate solids. The arsenic fixing process has the advantages of simple process, low cost, good treatment effects, low environmentalpollution risk and the like and is applicable to non-ferrous metal metallurgy industries.

The invention discloses a harmless arsenic solidifying method for industrial wastewater containing arsenic, and belongs to the field of arsenic pollution control. The harmless arsenic solidifying method includes the steps: the industrial wastewater containing the arsenic is subjected to pre-neutralization treatment; iron salt and an oxidant are added to a solution after pre-neutralization to solidify the arsenic into iron arsenate precipitation arsenic slag, and a neutralizer is used for controlling the process pH; and the iron arsenate precipitation arsenic slag is transformed into scoroditestabilization slag in a high-temperature aqueous solution by high-temperature mineralization. According to the harmless arsenic solidifying method for the industrial wastewater containing arsenic, standardized discharge of the industrial wastewater containing the arsenic can be realized, meanwhile, the arsenic is solidified into the scorodite stabilization slag, the technological process is simple, and the efficiency of arsenic removing and solidifying is high.

A filtering device for the removal of arsenic from the ground water/surface water. The filtering device of the present invention uses steel wool and sand as the raw material for the removal of arsenic from water and the entire outer body of the device can be made from cheaper material like plastic material or stainless steel. The filtering device works on the simple principle of co-precipitation of arsenic with metals, followed by adsorption and filtration through treated sand. The metal, steel wool, used in the device is a processed waste generated from a steel plant thereby making the device extremely cheaper and versatile. In the filtering device of the present invention, iron arsenate and iron arsenite are co-precipitated by the reaction of steel wool with arsenic in water. The device uses treated river sand simultaneously for the removal of iron leached out during reaction.

The invention discloses a treatment process for copper smelting smoke dust. The treatment process comprises the following steps that 1, after the copper smelting smoke dust is subjected to acid leaching, acid leaching liquor and acid leaching residues are obtained; 2, after the acid leaching liquor obtained in the step 1 is subjected to copper depositing through metal replacement, filter liquor with copper being deposited is obtained; 3, after the filter liquor with the copper being deposited in the step 2 neutralizes and oxidizes with alkali, ferric arsenate and filter liquor with arsenic being deposited are obtained; 4, after the filter liquor with arsenic being deposited in the step 3 is subjected to the secondary copper depositing through metal replacement, filter liquor being subjected to the secondary copper depositing and copper residues are obtained; and 5, after the filter liquor being subjected to the secondary copper depositing in the step 4 is subjected to zinc depositing through vulcanization, filter liquor with zinc being deposited and zinc residues are obtained. According to the treatment process for the copper smelting smoke dust provided by the invention, particularly, a treatment process for high-arsenic low-copper smoke dust, the harmless treatment of arsenic in the high-arsenic low-copper smoke dust is achieved; meanwhile, valuable metal copper, zinc, lead, bismuth and the like in the high-arsenic low-copper smoke dust are recovered comprehensively, and gradient recycle and comprehensive utilization of the impurities of the smoke dust are achieved.