CN1133593C - Electric ally caltalytic contact oxidizing technology - Google Patents

Abstract

The present invention relates to an electric catalysis contact oxidizing technology. In the formula, a catalyst is titanium dioxide or vanadium pentoxide, and filling materials are molecular sieves, activated carbon, zeolite or sand. Moreover, the filling materials and the catalyst are put into a reactor, and waste water is introduced into the reactor. Voltage is added to the process of a reaction, and oxygen is introduced to the reaction. The waste water stays in the reactor for 20 minutes to 10 hours, and the processed water is led out of the reactor. The technology has the advantages of short technological processes and low water treatment cost per ton, and completely solves the problems of decolorization of printing and dyeing waste water and thorough degradation of organic matters.

Description

Electrocatalytic contact oxidation process

The electrocatalysis contact oxidation method in the technical field is a method for treating printing and dyeing wastewater and wastewater containing refractory organics.

The dyes used in the printing and dyeing industry in the background technology are basically artificially synthesized chemical dyes, and because the chemical dyes have the characteristics of multiple varieties, complex structure, difficult decolorization, poor biodegradability and the like, the problems which are not well solved are always solved at home and abroad, the chromaticity of printing and dyeing wastewater brings great difficulty for wastewater treatment and recycling, becomes an obstacle for realizing wastewater recycling, and is a problem to be solved urgently in the field of environmental science research.

The waste water containing refractory organic matters brings great pollution to the environment due to poor biodegradability, and is a technical problem which is concerned about and needs to be solved for many years in the research field.

The two organic pollutants have certain treatment difficulty and high treatment cost. The traditional treatment method comprises a chemical coagulation method, a chemical oxidation method, an adsorption method, scrap iron filtration, biochemistry and other methods, and in the actual engineering, a satisfactory effect is difficult to obtain by only using one treatment means, so that the actual engineering adopts a plurality of unit combined processes, the result is that the treatment process route is long and complicated, the treatment cost is high, the indexes of pollutants after treatment still cannot reach the emission standards required by national control, and the standards mainly refer to the chromaticity and the COD value.

The invention relates to an electrocatalytic contact oxidation method, which aims to solve the problems of standard discharge or recycling of printing and dyeing wastewater and refractory organic wastewater, namely shortening the process flow and fundamentally solving the difficulties of decolorization and organic matter degradation which cannot be solved by the prior art.

The mechanism of the invention is that organic matters in the wastewater are difficult to be oxidized at normal temperature and even in the presence of a catalyst, but when voltage is applied, oxygen adsorbed on the surface of the catalyst used by the invention can form oxygen-containing free radicals, and the catalyst has the advantages ofThe filler used in the invention plays roles of electric polarization, adsorption and dispersion, so that the organic matters in the wastewater can be continuously oxidized and decomposed when enough oxygen is provided. The catalytic-oxidation reaction process is completed in one reactor, and the technical problems of decoloration of printing and dyeing wastewater and degradation of organic matters are thoroughly solved only by one unit operation, and the reaction formula is expressed as follows:

the technical scheme of the invention is that a catalyst and a filler are placed in a reactor, wastewater is introduced into the reactor, voltage is applied in the reaction process, air is introduced, the wastewater stays in the reactor for 20 minutes to 10 hours, and the treated water is led out of the reactor, wherein the catalyst is titanium dioxide or vanadium pentoxide, the filler is a molecular sieve, activated carbon, zeolite or sand grains, and the ratio of the catalyst to the filler is 1: 9.

The amount of the catalyst is 10-90% of the amount of water to be treated.

The reaction was carried out under the following conditions:

a. the temperature of the wastewater is 15-25 ℃,

b. the atmospheric pressure is 0.8 to 1.2 atmospheres,

c. the pH value of the wastewater is 3-8,

d. the concentration COD of the organic matters in the wastewater is below 2000mg/L,

e. the voltage is 5-50V,

f. the air is continuously introduced.

The shape of the titanium dioxide or vanadium pentoxide as the catalyst can be powder or granular, and the filler is as follows: molecular sieve, active carbon, zeolite or sand grains, wherein the filler plays the roles of electric polarization, adsorption and dispersion and increases the collision probability between reactants and a catalyst, and the reaction conditions are as follows: the water temperature of the wastewater is 0-40 ℃, the optimal temperature is 15-25 ℃, the atmospheric pressure is 0.8-1.2 atmospheric pressure, the pH value of the wastewater is 1-14, the optimal temperature is 6-8, the organic matter concentration COD of the wastewater is below 2000mg/L, the catalyst and the filler are uniformly mixed according to the proportion of 1: 9, or the catalyst can be fixed on the filler according to the same proportion, then the wastewater is put into a reactor together, the catalyst and the wastewater to be treated are in the proportion that the catalyst amount is 10% -90% of the wastewater amount to be treated, the voltage of 5-50V is applied to two ends of an electrode of the reactor to accelerate the speed of catalysis-oxidation, air is continuously introduced through an aeration pipe to ensure that enough oxygen exists in the reaction process, the retention time of the wastewater in the reactor is 20 minutes-10 hours, and the treated water is led out of the reactor.

The invention has the advantages that the degradation-resistant organic substances such as artificially synthesized dyes in the printing and dyeing wastewater can be completely oxidized in the presence of a catalyst, voltage and sufficient oxygen, the water quality index after treatment completely reaches the national discharge standard, and the technology is an excellent method for treating the printing and dyeing wastewater and the wastewater containing the degradation-resistant organic substances. The invention has the advantages of short process route, simple equipment, small occupied area and the like, not only reduces the cost per ton of water treatment, but also completely solves the problems of decoloration of printing and dyeing wastewater and full degradation of organic matters.

The present invention will be further described with reference to the following examples. The invention is implemented as follows:

the method of the invention is used for treating printing and dyeing wastewater of a certain factory at normal temperature and normal pressure, and comprises the following steps:

the first step is as follows: water quality investigation:

organic matter concentration COD: 1190mg/L

Wastewater chromaticity: 450 times of

pH of wastewater: 3

Temperature of wastewater: 20 deg.C

The second step is that: fixing 20 g of titanium dioxide on a 180 g molecular sieve, placing the titanium dioxide in a reactor, adding 1 liter of wastewater, applying a voltage of 20V to two ends of an electrode of the reactor to accelerate the speed of catalysis and oxidation, continuously introducing air through an aeration pipe to ensure that enough oxygen exists in the reaction, enabling the whole reactor to be like a boiling bed, allowing the wastewater to stay in the reactor for 30 minutes for full reaction, and finally leading the treated water out of the reactor.

The third step: the water quality inspection result after treatment is as follows:

organic matter concentration COD: 70mg/L

Chroma: 30 times of

pH value: 6

Water temperature after treatment: 20 deg.C

The water quality after treatment reaches the national second-level discharge standard.

Claims (3)

1. The electrocatalytic contact oxidation method is characterized in that a catalyst and a filler are placed in a reactor, wastewater is introduced into the reactor, voltage is applied in the reaction process, air is introduced, the wastewater stays in the reactor for 20 minutes to 10 hours, and the treated water is led out of the reactor, wherein the catalyst is titanium dioxide or vanadium pentoxide, the filler is a molecular sieve, activated carbon, zeolite or sand grains, and the ratio of the catalyst to the filler is 1: 9.

2. The catalytic contact oxidation process of claim 1, wherein the amount of the catalyst is 10% to 90% of the amount of water to be treated.

3. The electrocatalytic contact oxidation process according to claim 1 or 2, characterized in that the reaction is carried out under the following conditions:

a. the temperature of the wastewater is 15-25 ℃,

b. the atmospheric pressure is 0.8 to 1.2 atmospheres,

c. the pH value of the wastewater is 3-8,

d. the concentration COD of the organic matters in the wastewater is below 2000mg/L,

e. the voltage is 5-50V,

f. the air is continuously introduced.