阅读说明：本技术 一种用于剧毒废水无害化处理的催化剂及其制备方法和应用 (Catalyst for harmless treatment of highly toxic wastewater and preparation method and application thereof ) 是由 朱作霖 朱振之 孙善庆 刘珂 解统兴 苗涛 于 2018-06-26 设计创作，主要内容包括：一种用于剧毒废水无害化处理的催化剂,其特征在于：包括特定过渡金属的氧化物和伽马氧化铝的混合物、含有特定过渡金属离子的中孔氧化铝中的至少一种；其中上述混合物中特定过渡金属的氧化物和伽马氧化铝之间的重量比为10:1～1:10；上述含有特定过渡金属离子的中孔氧化铝中特定过渡金属/(特定过渡金属+铝)的重量比为1～20％,且含有特定过渡金属离子的中孔氧化铝的孔径为5～50纳米；上述特定过渡金属包括锰、铁、锌中的至少一种。本发明还公开了上述催化剂的制备方法和应用。本发明的催化剂不会受到剧毒物质的毒化,制备方法简单,与氧化剂配合能有效降解废水中的多种剧毒物质,并同时能够降解废水中的有机污染物。(A catalyst for harmless treatment of highly toxic wastewater is characterized in that: at least one of a mixture comprising an oxide of a specific transition metal and gamma alumina, mesoporous alumina containing ions of a specific transition metal; wherein the weight ratio of the oxide of the specific transition metal to the gamma alumina in the mixture is 10: 1-1: 10; the weight ratio of the specific transition metal/(specific transition metal + aluminum) in the mesoporous alumina containing the specific transition metal ions is 1-20%, and the aperture of the mesoporous alumina containing the specific transition metal ions is 5-50 nm; the specific transition metal includes at least one of manganese, iron and zinc. The invention also discloses a preparation method and application of the catalyst. The catalyst of the invention can not be poisoned by highly toxic substances, has simple preparation method, can effectively degrade various highly toxic substances in the wastewater by matching with the oxidant, and can degrade organic pollutants in the wastewater at the same time.)

1. A catalyst for harmless treatment of highly toxic wastewater is characterized in that: at least one of a mixture comprising an oxide of a specific transition metal and gamma alumina, mesoporous alumina containing ions of a specific transition metal; wherein the weight ratio of the oxide of the specific transition metal to the gamma alumina in the mixture is 10: 1-1: 10, and the oxide of the specific transition metal and the gamma alumina are respectively particles of 100-300 nanometers; the weight ratio of the specific transition metal/(specific transition metal + aluminum) in the mesoporous alumina containing the specific transition metal ions is 1-20%, and the aperture of the mesoporous alumina containing the specific transition metal ions is 5-50 nm; the specific transition metal includes at least one of manganese, iron and zinc.

2. The catalyst of claim 1, wherein: the weight ratio of the specific transition metal/(the specific transition metal + aluminum) in the mesoporous alumina containing the specific transition metal ions is 6-8%.

3. A method of preparing the catalyst of claim 1, wherein: the preparation method of the mixture of the oxide of the specific transition metal and the gamma alumina comprises the following steps: respectively crushing an oxide of a specific transition metal and gamma alumina into particles of 100-300 nanometers, and then adding the particles into an aqueous solution containing a nonionic surfactant and volatile organic alcohol, wherein the volume fraction of water in the aqueous solution is 0-20%, the nonionic surfactant comprises one of Pluronic P123 and F127, the weight content of the nonionic surfactant is 1-2%, and the total weight content of the oxide of the specific transition metal and the gamma alumina is 1-10%; stirring for 10-24 hours at normal temperature and normal pressure, and slowly evaporating for 5-6 days at 40-60 ℃ to obtain the mixture catalyst of the oxide of the specific transition metal and the gamma alumina.

4. A method of preparing the catalyst of claim 1, wherein: the preparation method of the mesoporous alumina containing the specific transition metal ions comprises the following steps: firstly, preparing an aqueous solution containing a nonionic surfactant and having volatile organic alcohol, wherein the volume fraction of water in the aqueous solution is 0-20%, the nonionic surfactant comprises one of Pluronic cP123 and F127, and the weight content of the nonionic surfactant is 1-2%; stirring and sequentially adding 0.5-1% by weight of organic acid, 10-20% by weight of aluminum nitrate and the nitrate of the specific transition metal, wherein the organic acid comprises at least one of citric acid, fumaric acid, maleic acid, aspartic acid and glutamic acid; slowly stirring for 5-30 hours under the protection of nitrogen, and slowly evaporating for 5-6 days at the temperature of 55-60 ℃ to obtain the mesoporous alumina catalyst containing the specific metal ions.

5. The method for preparing a catalyst according to claim 3 or 4, characterized in that: the organic alcohol comprises methanol, ethanol or isopropanol.

6. Use of a catalyst according to claim 1 or 2 for the harmless treatment of highly toxic waste water.

7. Use according to claim 6, characterized in that the method of application comprises the steps of:

providing waste water containing highly toxic substances;

secondly, adding the catalyst and the oxidant into the wastewater, and reacting for 1-24 hours; and the molar equivalent of the catalyst and the oxidant which are added is 0.1-20% and 1-20 times of the molar equivalent of the highly toxic substances in the wastewater respectively.

8. Use according to claim 7, characterized in that: the molar equivalent of the catalyst input in the step II is 1-10% of the molar equivalent of the highly toxic substances in the wastewater.

9. Use according to claim 7, characterized in that: the oxidant is ozone.

10. Use according to claim 7, characterized in that: the highly toxic substances comprise highly toxic organic matters and/or highly toxic inorganic matters, wherein the highly toxic organic matters comprise at least one of organic pesticides such as organic phosphorus, organic silicon, polyfluoro polychlorinated organic matters, organic sulfur, organic mercury and the like; the highly toxic inorganic substance includes at least one of chemical weapon reagent, free hydrogen cyanide, stable metal cyanide, thiocyanide, stable thiocyanide, etc.

Technical Field

The invention belongs to the technical field of wastewater treatment, and particularly relates to a catalyst for harmless treatment of highly toxic wastewater, and a preparation method and application thereof.

Background

The existing methods for harmlessly treating waste water containing highly toxic substances have the defects of the methods. For example, in the Treatment of Cyanide-Containing wastewater as evaluated by the U.S. Environmental Protection Agency (EPA) (Treatment Technologies for Metal/Cyanide containment waters, Volume III, EPA/600/S2-87/106Feb.1988), the anionic resin method (anion exchange resins) requires a second Treatment of the resin Containing the toxicant; the alkaline chlorination process (alkalinechlorination) fails to treat stable metal cyanides; ozone oxidation (ozone) can only handle low concentrations of free cyanide; wet oxidation (wet air oxidation) does not oxidize completely, requiring further treatment of the resulting liquids and gases; sulfur-based oxidation (sulfur-based treatment) is also an incomplete process requiring further treatment of the resulting liquids and gases; microbial Treatment processes (Biological Treatment Methods) are too slow; the high temperature Incineration (inceration) is too costly and requires the disposal of waste gases and slag.

To overcome the drawbacks of the above treatment methods, ozone combined with ultraviolet photon catalysis (O), and ozone and hydrogen peroxide combined with ultraviolet photon catalysis (O) are used₃/UV or O₃/H₂O₂UV, Advanced oxidation processes for the removal of cyanide from thermal power stations waters, journal of Chemical Technology and Biotechnology, December 2013), but this approach suffers from the disadvantages of too slow degradation rate, large effect on salt concentration in the water, and ineffective degradation of organic contaminants in the wastewater.

There are technologies combining ion exchange and wet oxidation, for example, japanese patent of oxidation and chemical compound, JPS6411695(a), discloses an oxidation Method using a metal catalyst, which has disadvantages that the degradation rate of hydrogen peroxide as an oxidant is fast, a large amount of hydrogen peroxide is required, and the risk of hydrogen cyanide gas release during the treatment process.

Meanwhile, there is also an Electrochemical degradation technology, for example, U.S. Pat. No. US8093442B2, Electrochemical removal of dissociable cyanides, discloses an Electrochemical degradation method, which has a fast degradation speed, but is basically ineffective for stabilizing metal cyanide, and has high energy consumption and risk of generating hydrogen cyanide gas.

In addition, the catalytic oxidation technology is a very common technology in wastewater treatment, and common oxidants are hydrogen peroxide, peroxy acid, potassium permanganate, elementary halogen and salts in high oxidation states thereof (such as sodium chlorate, sodium hypochlorite and the like), oxygen, persulfate, peroxycarbonate, ozone and the like; common catalysts are transition metal elements or their oxides, such as iron, manganese, copper, silver, nickel, cobalt, palladium, platinum, gold, etc., and there are tens of thousands of related patents, such as CN201310288446.4, CN201310288437.5, etc. The known methods can well remove organic pollutants in the wastewater and effectively reduce the COD of the wastewater. However, if the wastewater contains highly toxic substances including organic sulfur, polyfluoro polychlorinated organic compounds, organic mercury, cyanides, metal cyanide complexes, etc., these known catalytic systems are either substantially ineffective or degrade only with low efficiency and at slow rates. Because, with these conventional catalysts, the highly toxic substances in the wastewater are generally poisoning agents for these catalysts, the original ability of these catalysts to degrade organic pollutants is essentially completely lost once the wastewater contains the highly toxic substances.

Currently, due to the precision of industrial development and the industrial cross-industrialization, wastewater containing a virulent substance is generated in many cases, and the wastewater contains a stable metal complex and an organic pollutant, so that it is very important to develop a catalyst that is not poisoned by the virulent substance, and to achieve the harmlessness of the virulent substance (including a very stable metal cyanide complex), and to effectively degrade the organic pollutant.

Disclosure of Invention

The first technical problem to be solved by the invention is to provide a catalyst for harmless treatment of highly toxic wastewater, which is convenient to produce, low in cost, high in degradation speed and degradation rate of the highly toxic wastewater and capable of effectively degrading organic pollutants in the wastewater, aiming at the current situation of the prior art.

The second technical problem to be solved by the invention is to provide a preparation method of the catalyst for harmless treatment of highly toxic wastewater, which is convenient to produce and low in cost, aiming at the current situation of the prior art.

The third technical problem to be solved by the present invention is to provide an application of the above catalyst in view of the current state of the art.

The technical scheme adopted by the invention for solving the first technical problem is as follows: a catalyst for harmless treatment of highly toxic wastewater is characterized in that: at least one of mesoporous alumina (mesoporus aluminum) containing a specific transition metal ion, a mixture comprising an oxide of a specific transition metal and gamma alumina (alumina whose crystal form is gamma-form); wherein the weight ratio of the oxide of the specific transition metal to the gamma alumina in the mixture is 10: 1-1: 10, and the oxide of the specific transition metal and the gamma alumina are respectively particles of 100-300 nanometers; the weight ratio of the specific transition metal/(specific transition metal + aluminum) in the mesoporous alumina containing the specific transition metal ions is 1-20%, and the aperture of the mesoporous alumina containing the specific transition metal ions is 5-50 nm; the specific transition metal includes at least one of manganese, iron and zinc (the catalyst using other transition metals does not have the catalytic ability of the catalyst of the present invention).

In the modified mesoporous alumina, the weight ratio of the specific transition metal/(the specific transition metal + aluminum) in the mesoporous alumina containing the specific transition metal ions is 6-8%.

The technical scheme adopted by the invention for solving the second technical problem is as follows: a method for preparing the catalyst, which is characterized by comprising the following steps: the preparation method of the mixture of the oxide of the specific transition metal and the gamma alumina comprises the following steps: respectively crushing an oxide of a specific transition metal and gamma alumina into particles of 100-300 nanometers, and then adding the particles into an aqueous solution containing a nonionic surfactant and volatile organic alcohol, wherein the volume fraction of water in the aqueous solution is 0-20%, the nonionic surfactant comprises one of Pluronic P123 and F127, the weight content of the nonionic surfactant is 1-2%, and the total weight content of the oxide of the specific transition metal and the gamma alumina is 1-10%; stirring for 10-24 hours at normal temperature and normal pressure, and slowly evaporating for 5-6 days at 40-60 ℃ to obtain the mixture catalyst of the oxide of the specific transition metal and the gamma alumina.

The preparation method of the mesoporous alumina containing the specific transition metal ions comprises the following steps: firstly, preparing an aqueous solution containing a non-ionic surfactant and having volatile organic alcohol, wherein the volume fraction of water in the aqueous solution is 0-20%, the non-ionic surfactant comprises one of Pluronic P123 and F127, and the weight content of the non-ionic surfactant is 1-2%; stirring and sequentially adding 0.5-1% by weight of organic acid, 10-20% by weight of aluminum nitrate and the nitrate of the specific transition metal, wherein the organic acid comprises at least one of citric acid, fumaric acid, maleic acid, aspartic acid and glutamic acid, and preferably citric acid; slowly stirring for 5-30 hours under the protection of nitrogen, and slowly evaporating for 5-6 days at the temperature of 55-60 ℃ to obtain the mesoporous alumina catalyst containing the specific metal ions.

The water content of the above-mentioned aqueous solution with a volatile organic alcohol of the present invention cannot be too high, otherwise the evaporation time would be prolonged, affecting the preparation efficiency.

Preferably, the organic alcohol comprises methanol, ethanol or isopropanol.

The organic alcohol or the aqueous solution of the organic alcohol of the present invention is used as a reaction medium, and at the same time, it is required to have a property of being volatile at a certain temperature (40 to 60 ℃), so the organic alcohol of the present invention is not limited to the above-mentioned ones, and any organic alcohol satisfying the above-mentioned two requirements can be used.

In the preparation process of the catalyst disclosed by the invention, a nonionic surfactant Pluronic P123 (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer with a molecular formula of PEO-PPO-PEO) or F127 (polyoxyethylene polyoxypropylene ether block copolymer with a molecular formula of HO · (C))₂H₄O)m·(C₃H₆O) n.h) is very critical, it first helps the reactants to form very good micelles (micella) in the solvent, and then ensures the catalyst to form uniformly distributed internal pores during slow evaporation. Without the use of such a nonionic surfactant, the resulting product has substantially no catalytic effect or, even if it has a catalytic function, is rapidly deactivated in highly toxic waste water.

The technical scheme adopted by the invention for solving the third technical problem is as follows: the application of the catalyst in harmless treatment of highly toxic wastewater.

The application method preferably comprises the following steps:

providing waste water containing highly toxic substances;

secondly, adding the catalyst and the oxidant into the wastewater, and reacting for 1-24 hours; and the molar equivalent of the catalyst and the oxidant which are added is 0.1-20% and 1-20 times of the molar equivalent of the highly toxic substances in the wastewater respectively.

The molar equivalent of the catalyst added in the step II is preferably 1-10% of the molar equivalent of the virulent substances in the wastewater.

In the above scheme, the oxidant is ozone. The catalyst of the invention can convert all ozone into intermediates with strong oxidizing ability, and the intermediates can instantaneously oxidize highly toxic substances and various organic pollutants in the wastewater.

The highly toxic substances comprise highly toxic organic matters and/or highly toxic inorganic matters, wherein the highly toxic organic matters comprise at least one of organic pesticides such as organic phosphorus, organic silicon, polyfluoro polychlorinated organic matters, organic sulfur, organic mercury and the like; the highly toxic inorganic substance includes at least one of chemical weapon reagent, free hydrogen cyanide, stable metal cyanide, thiocyanide, stable thiocyanide, etc.

Compared with the prior art, the invention has the advantages that: by selecting a mixture of the oxide of the specific transition metal and the gamma alumina or/and the mesoporous alumina containing the specific transition metal ions as the catalyst, the catalyst is not poisoned by the highly toxic substances, has high catalytic capability in the highly toxic wastewater and good effect, and overcomes the defect that the specific transition metal oxide or the specific transition metal salt is poisoned by the highly toxic substances when being singly used; the preparation method of the catalyst is simple and low in cost, and the catalyst forms uniform internal gaps by adding the nonionic surfactant, so that the catalytic activity and the catalytic effect are ensured; when the catalyst is applied to wastewater treatment, the catalyst is matched with an oxidant, can effectively degrade various highly toxic substances including stable metal cyanide complexes in wastewater, and can degrade organic pollutants in the wastewater.

Detailed Description

The present invention will be described in further detail with reference to examples.