Method of treating aniline waste water through photo-catalytic oxidation

Abstract

The invention provides a method of treating aniline waste water through photo-catalytic oxidation and belongs to the technical field of industrial waste water treatment. The method includes the step of catalytically oxidizing the aniline pollutant into CO2, H2O and small-molecular organic substances in the presence of an oxidizing agent under irradiation of ultraviolet light. The method can be used for treating the aniline waste water in the fields of refining chemical engineering, printing and dyeing, pharmacy and the like. The method is quick in reaction speed, is complete in deep oxidization, is economic and high-effective in treatment process and is free of secondary pollution. A test proves that the method is higher than 90% in removal rates of both the aniline substances and chromaticity in the aniline waste water in various industries, and treated water satisfies the first-grade standard requirement in national pollutant integrated emission standard (GB8978-1996).

Description

technical field [0001] The invention relates to a method for treating aniline wastewater, in particular to a method for treating aniline wastewater by photocatalytic oxidation, and belongs to the field of industrial sewage treatment in environmental protection. technical background [0002] Aniline compounds are important organic chemical raw materials and fine chemical intermediates, but also harmful substances that seriously pollute the environment and endanger human health. Many domestic refineries, dye factories, pesticide factories, etc. will produce a large amount of aniline wastewater in the production process, and its mass concentration can sometimes be as high as several thousand mg / L. Due to the toxicity of aniline substances to ecological organisms, it has been included in the "China Environmental Priority Pollutants Blacklist", and strict control is required in industrial drainage. At present, the compliance rate of aniline pollutants in my country is very low, ...

AI Technical Summary

Problems solved by technology

At present, the compliance rate of aniline pollutants in my country is very low, and the task of treatment is very arduous

[0003] So far, there are mainly biological, physical, chemical and other methods for the treatment of aniline wastewater at home and abroad, but the treatment effect of most methods is not ideal, and there are common problems such as high cost, serious secondary pollution, and substandard discharge.

For example, the method for treating aniline wastewater disclosed in Chinese patent application 200810113140.4 is to first treat high-concentration nitrobenzene and aniline wastewater through flocculation and sedimentation, and then pass through multi-stage immobilized microorganism-anaerobic biofilter and immobilized microorganism-exposure Gas biological filter treatment, the technical process is long, the hydraulic retention time is long, the activity of microorganisms is difficult to maintain stable, the amount of flocculant is large and it is difficult to recycle and reuse, and the sludge generated by flocculation is still a problem

Chinese patent application 201010513837.8 discloses the combined process of ozone oxidation-modified activated carbon / modified montmorillonite adsorption to treat aniline wastewater. It uses ozone to initially oxidize the wastewater, and then flows the wastewater into the modified activated carbon adsorption pool and modified montmorillonite. Soil removal adsorption pool, aniline pollutants are adsorbed and removed. It is a treatment technology combined with physical method and chemical method. The degree of oxidation of aniline by ozone is very limited, and the preparation of modified activated carbon and modified montmorillonite adsorbents used is relatively complicated. Moreover, it is difficult to regenerate the adsorbent, and it is prone to the problem that the wastewater discharge does not meet the standard

Both patents 201310412791.4 and 201310572601.5 use Fenton catalytic degradation reaction to treat aniline wastewater. They decompose H 2 o 2 The generated hydroxyl radicals degrade macromolecular aniline into small molecular organics or mineralize into CO 2 and H 2 O and other inorganic substances to achieve the purpose of purifying wastewater. The biggest disadvantage of this method is that a large amount of sludge will be generated during the purification process of aniline wastewater, which increases the difficulty and cost of secondary treatment for enterprises.

As another example, patent 201410593332.5 adopts the combination technology of formaldehyde polycondensation-Fenton oxidation-NaClO oxidation to treat aniline wastewater, mixes the wastewater and formaldehyde solution and heats it for polycondensation reaction, and then adds Fenton reagent for reaction after sedimentation and filtration, and then adds NaClO solution for reaction after filtration. The process route is complicated. The polycondensation and Fenton and NaClO oxidation processes need to constantly adjust the reaction temperature and pH. At the same time, difficult-to-handle sludge and solid waste will be continuously produced, and formaldehyde is toxic. NaClO will corrode pipes and equipment, causing serious secondary pollution.

Patents 201410470749.2 and 201410565086 respectively use iron-carbon micro-electrolysis and catalytic iron-inner micro-electrolysis to treat nitrobenzene and aniline wastewater. Although the new micro-electrolysis technology is currently a popular new water treatment method, it cannot treat nitrobenzene The compound is completely mineralized into small inorganic molecules, which can only be used in combination with other processes as a pretreatment method for wastewater

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