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CN-121669252-B - Mo-Ni bimetallic denitration catalyst and preparation method thereof

CN121669252BCN 121669252 BCN121669252 BCN 121669252BCN-121669252-B

Abstract

The invention discloses a Mo-Ni bimetallic denitration catalyst and a preparation method thereof, and relates to the technical field of denitration agents, wherein the preparation method comprises the steps of firstly smelting a nickel source, a molybdenum source and an aluminum source and crushing to obtain Ni-Mo-Al ternary alloy powder; the catalyst prepared by the method has a macroporous structure with conductive micro powder distributed on the inner wall, the unique structure not only reduces mass transfer resistance, builds an electron transmission channel, but also promotes the discharge of product nitrogen through a local hydrophobic environment, and remarkably improves catalytic activity and nitrogen selectivity when nitrate-containing wastewater is treated.

Inventors

  • ZOU LINGFENG
  • CHAO ZISHENG

Assignees

  • 长沙理工大学

Dates

Publication Date
20260512
Application Date
20260212

Claims (9)

  1. 1. The preparation method of the Mo-Ni bimetallic catalyst for removing nitrate by catalytic reduction is characterized by comprising the following steps of: (1) Smelting a nickel source, a molybdenum source and an aluminum source in proportion, cooling, crushing, grinding and sieving to obtain Ni-Mo-Al ternary alloy powder; (2) Preparing a mixed alkaline leaching solution containing alkali metal hydroxide, a surfactant and hydrophobic conductive micro powder, and uniformly suspending the hydrophobic conductive micro powder by a dispersing means; (3) Adding Ni-Mo-Al ternary alloy powder into the mixed alkaline leaching solution, and carrying out dealumination reaction under the heating condition; (4) After the reaction is finished, carrying out solid-liquid separation, washing and drying on a solid product to obtain the Mo-Ni bimetallic catalyst; In the step (1), the mass ratio of Ni, mo and Al in the Ni-Mo-Al ternary alloy powder is 35-45:0.5-5:50-60.
  2. 2. The method according to claim 1, wherein in the step (1), the particle size range after crushing and grinding is 100 to 300 mesh.
  3. 3. The method according to claim 1, wherein in the step (2), the alkali metal hydroxide is sodium hydroxide or potassium hydroxide, the concentration of the alkali metal hydroxide in the mixed alkaline leaching solution is 15-25wt%, the surfactant is at least one of a cationic surfactant, an anionic surfactant and a nonionic surfactant, the concentration of the surfactant is 0.05-0.5wt%, and the hydrophobic conductive micro powder is at least one of a hydrophobically modified carbon nanotube, graphene, carbon black, graphite powder or conductive polymer microsphere, and the content of the hydrophobic conductive micro powder in the mixed alkaline leaching solution is 0.1-2.0 g/L.
  4. 4. The method according to claim 1, wherein in the step (3), the solid-to-liquid ratio of the ni—mo—al ternary alloy powder to the mixed alkaline leaching solution is 1g:10 to 20ml.
  5. 5. The preparation method according to claim 1, wherein in the step (3), the dealumination reaction is performed at a temperature of 60-90 ℃ for a reaction time of 1-4 hours.
  6. 6. The method according to claim 1, wherein in the step (3), intermittent low-speed stirring or stationary leaching is employed at the beginning of the addition of the alloy powder to maintain the hydrogen bubbles at the solid-liquid interface.
  7. 7. The preparation method of claim 1, wherein in the step (4), deionized water and absolute ethyl alcohol are sequentially used for washing until the pH value of a washing liquid is 7-8, and the drying is performed at 40-60 ℃ under the protection of vacuum degree of less than-0.08 MPa or inert gas.
  8. 8. The Mo-Ni bimetallic catalyst prepared by the preparation method according to any one of claims 1-7, wherein the catalyst has a macroporous structure with the inner wall distributed with the hydrophobic conductive micro powder, the mass content of Mo element in the catalyst is 0.5-10%, the mass content of the hydrophobic conductive micro powder is 0.1-5.0%, the mass content of residual Al element is 2.0-12.0%, and the balance is Ni and unavoidable impurities.
  9. 9. Use of the mo—ni bimetallic catalyst of claim 8 for treating nitrate-containing wastewater.

Description

Mo-Ni bimetallic denitration catalyst and preparation method thereof Technical Field The invention relates to the technical field of denitration agents, in particular to a Mo-Ni bimetallic denitration catalyst and a preparation method thereof. Background With the rapid development of modern industry, the concentration of nitrogen-containing pollutants (especially nitrate ions) in industrial wastewater is increasingly higher, and the nitrogen-containing pollutants become one of the main factors of water environment pollution. Nitrate can not only cause eutrophication of water, but also cause serious harm to human health. Therefore, development of efficient nitrate wastewater treatment technology has become an important issue in the field of environmental protection. Currently, main methods for industrially treating nitrate-containing wastewater include a biological denitrification method, a physical adsorption method, a membrane separation method, a catalytic reduction method, and the like. Although the biological denitrification method has relatively low cost, the method has strict requirement on the C/N ratio of the wastewater, long treatment period, large occupied area and poor treatment effect on the high-concentration nitrate wastewater, and is difficult to meet the requirement of modern industry on efficient treatment. Although the physicochemical methods such as ion exchange and reverse osmosis have higher treatment efficiency, the physicochemical methods have the defects of high operation cost, secondary pollution, complex equipment maintenance and the like, and are difficult to popularize and apply in large-scale industrial wastewater treatment. The catalytic reduction method gradually becomes a research hot spot due to the advantages of high reaction speed, high treatment efficiency and the like. The method reduces nitrate radical into harmless nitrogen by using a reducing agent through the action of a catalyst. The catalyst systems currently under investigation mainly comprise noble metal catalysts and non-noble metal catalysts. Noble metal catalysts (such as palladium-based catalysts and platinum-based catalysts) have certain catalytic activity, but are extremely expensive, and are easy to lose metals to cause deactivation, so that industrial large-scale application is difficult to realize. Although the non-noble metal catalyst is low in cost, the following technical problems are common in the nitrate reduction process: (1) The existing catalyst often generates a great deal of ammonia nitrogen byproducts when nitrate radical is reduced, so that incomplete denitrification and even secondary pollution are caused. (2) The catalytic activity is to be improved, the whole catalytic efficiency of the existing catalyst is not high enough, and the requirements of rapid and efficient treatment of industrial wastewater are difficult to meet. (3) Mass transfer performance is limited, namely mass transfer diffusion resistance exists in the liquid phase reaction of the existing catalyst, so that the utilization rate of the catalyst is low, and the integral treatment effect is influenced. Aiming at the problems, various improvement methods including carrier modification, structure regulation and the like are tried in the prior art, but the problems of complex preparation process, high cost, poor stability and the like generally exist in the methods, and the technical problems of catalytic activity and selectivity are difficult to solve simultaneously. Particularly in the aspects of catalyst pore structure design and surface modification, the existing preparation method is difficult to realize accurate structure control, and the mass transfer performance and selectivity requirements cannot be effectively balanced. In summary, the conventional nitrate catalytic reduction technology still has obvious defects in key technical indexes such as catalytic activity, reaction selectivity and mass transfer performance, and is difficult to meet the actual requirements of modern industrial wastewater treatment. Therefore, development of a novel denitration catalyst and a preparation method thereof are urgently needed to solve the technical problems existing in the prior art, realize efficient and high-selectivity nitrate removal, and meet the requirements of industrial application. Disclosure of Invention In order to solve the defects existing in the prior art, the invention aims to provide a Mo-Ni bimetallic denitration catalyst and a preparation method thereof, according to the invention, by combining alloy smelting and in-situ bubble pore-forming technology, a hierarchical macroporous structure embedded with conductive micro powder is constructed on the basis of keeping Raney Ni high specific surface area. The process is simple and controllable, the optimization of the pore channel structure of the catalyst, the improvement of the electron transmission capacity and the regulation and control of the local microenvironment