阅读说明：本技术 一种促进废水中甲醛氧化的催化剂及其制备方法 (Catalyst for promoting formaldehyde in wastewater to be oxidized and preparation method thereof ) 是由 杨如清 于 2021-03-02 设计创作，主要内容包括：本发明提供一种促进废水中甲醛氧化的催化剂及其制备方法,包括：二氧化硅、二氧化锰、纳米铁、硫酸钙、银粉,这些组分的质量比为1：(1.8～2.2)：(2.4～2.8)：(0.8～1.2)：(0.005～0.008)；所述催化剂为固体多孔隙颗粒,粒径5～10mm。本发明的催化剂,在常温常压的条件下,与双氧水反应可以生成超氧自由基,可使废水中甲醛的氧化率可达99.9%以上,但废水中其它有机物的氧化率不到1%,因而有选择性地去除甲醛,不造成药剂浪费,同时不产生固废和废气,没有二次污染；同时,催化剂在催化氧化反应始末不发生化学性质的变化,且性能也不会发生衰减,可以反复长时间使用。(The invention provides a catalyst for promoting formaldehyde in wastewater to be oxidized and a preparation method thereof, wherein the catalyst comprises the following components: the composite material comprises silicon dioxide, manganese dioxide, nano iron, calcium sulfate and silver powder, wherein the mass ratio of the components is 1: (1.8-2.2): (2.4-2.8): (0.8-1.2): (0.005-0.008); the catalyst is solid porous particles with the particle size of 5-10 mm. The catalyst can react with hydrogen peroxide to generate superoxide radical under the conditions of normal temperature and normal pressure, so that the oxidation rate of formaldehyde in the wastewater can reach more than 99.9 percent, but the oxidation rate of other organic matters in the wastewater is less than 1 percent, and therefore, the formaldehyde is selectively removed, the medicament waste is not caused, and simultaneously, solid waste and waste gas are not generated, and no secondary pollution is caused; meanwhile, the catalyst does not change in chemical properties from the beginning to the end of the catalytic oxidation reaction, does not attenuate in performance, and can be repeatedly used for a long time.)

1. A catalyst for promoting the oxidation of formaldehyde in wastewater, comprising: the composite material comprises silicon dioxide, manganese dioxide, nano iron, calcium sulfate and silver powder, wherein the mass ratio of the components is 1: (1.8-2.2): (2.4-2.8): (0.8-1.2): (0.005-0.008).

2. The catalyst for promoting the oxidation of formaldehyde in wastewater according to claim 1, wherein the catalyst is solid porous particles with the particle size of 5-10 mm.

3. The method for preparing a catalyst for promoting the oxidation of formaldehyde in wastewater according to claim 1 or 2, comprising the steps of: (1) uniformly mixing the silicon dioxide, the manganese dioxide, the nano iron, the calcium sulfate and the silver powder, and melting at 1600-1900 ℃; (2) cooling to 540-580 ℃, injecting into a mold for condensation nucleation; (3) and sprinkling 5-10 ℃ of water when the surface temperature of the catalyst is reduced to 270-330 ℃, thus obtaining the catalyst.

4. The catalyst for promoting the oxidation of the formaldehyde in the wastewater as claimed in claim 1 or 2, which is used in combination with hydrogen peroxide to catalyze the oxidation reaction of the formaldehyde in the wastewater.

5. The catalyst for promoting the oxidation of formaldehyde in wastewater according to claim 4, wherein the ratio of the catalyst to 27.5% by mass of hydrogen peroxide in unit reaction time under the reaction condition that the pH of wastewater is 7.5-9.0 is (1-1.5): 1.

6. the catalyst for promoting the oxidation of formaldehyde in wastewater according to claim 5, wherein the pH value of the wastewater is 8.5-9.

Technical Field

The invention belongs to the field of organic chemical wastewater treatment, and particularly relates to a catalyst for promoting formaldehyde in wastewater to be oxidized and a preparation method thereof.

Background

The formaldehyde has biological toxicity, and is difficult to be treated by a biological method when the formaldehyde content of the wastewater is higher than 200mg/L, and the formaldehyde in the wastewater needs to be pretreated firstly. At present, the catalytic oxidation technology is adopted to carry out more methods for pretreating formaldehyde, such as: iron-carbon micro-electrolysis, Fenton oxidation, ozone activated carbon catalytic oxidation, wet oxidation, photocatalytic oxidation and the like. Although these methods can oxidize formaldehyde in wastewater, they can remove formaldehyde by oxidizing all organic substances in wastewater at the same time. However, oxidation of organic materials that do not need to be oxidized consumes most of the chemicals and energy, resulting in excessive operating costs.

Disclosure of Invention

The invention aims to provide a catalyst for promoting formaldehyde in wastewater to be oxidized, which aims to solve the following problems in the prior catalytic oxidation technology: (1) formaldehyde can not be oxidized in a targeted manner, and organic matters which do not need to be oxidized are simultaneously oxidized by the added oxidant, so that the waste of the medicament is caused; (2) the reaction conditions are harsh, such as high temperature, high pressure, strong ultraviolet irradiation, strong acid and the like, large energy consumption is needed, and the risk of accidents is increased; (3) the reaction is dangerous and solid waste or polluting waste gas, so that secondary pollution is caused; the above points all result in high investment and operation cost.

The purpose of the invention is realized by the following technical scheme:

the invention relates to a catalyst for promoting formaldehyde in wastewater to be oxidized, which is characterized by comprising the following components: the composite material comprises silicon dioxide, manganese dioxide, nano iron, calcium sulfate and silver powder, wherein the mass ratio of the components is 1: (1.8-2.2): (2.4-2.8): (0.8-1.2): (0.005-0.008).

Furthermore, the catalyst is solid porous particles with the particle size of 5-10 mm.

The invention discloses a preparation method of a catalyst for promoting formaldehyde oxidation in wastewater, which is characterized by comprising the following steps of: (1) uniformly mixing the silicon dioxide, the manganese dioxide, the nano iron, the calcium sulfate and the silver powder, and melting at 1600-1900 ℃; (2) cooling to 540-580 ℃, injecting into a mold for condensation nucleation; (3) sprinkling 5-10 ℃ of water when the surface temperature of the catalyst is reduced to 270-330 ℃ to obtain the catalyst; the method utilizes the instant vaporization of the soaked water to punch the interior of the catalyst into pores, utilizes the different coefficients of thermal expansion and cold contraction of the components in the catalyst to crack various fine lines under the instant cooling, and provides the surface area in the catalyst through the physical actions, thereby improving the reaction contact area of the catalyst and further improving the catalytic efficiency.

The catalyst for promoting the oxidation of formaldehyde in the wastewater is matched with hydrogen peroxide for use and is used for catalyzing the oxidation reaction of formaldehyde in the wastewater; in unit reaction time (for example, 1 hour), under the reaction condition that the PH of the wastewater is 7.5-9.0, the proportion of the catalyst to 27.5% hydrogen peroxide by mass concentration is (1-1.5): 1.

furthermore, the catalyst for promoting the oxidation of formaldehyde in the wastewater has certain requirements on the pH of the wastewater in the use process, the effect is general under an acidic condition, the effect is good under alkaline regulation, and the pH value of the wastewater is preferably 7.5-9, and more preferably 8.5-9.

Compared with the prior art, the invention has the following advantages:

the catalyst for promoting the oxidation of formaldehyde in the wastewater can react with hydrogen peroxide to generate superoxide radical under the conditions of normal temperature and normal pressure, and catalyze the formaldehyde in the wastewater to generate oxidation reaction and convert the formaldehyde into non-toxic chemical substances such as formic acid, carbon dioxide and the like, so that the oxidation rate of the formaldehyde in the wastewater can reach more than 99.9 percent, but the oxidation rate of other organic matters in the wastewater is less than 1 percent, thereby selectively removing the formaldehyde, not causing medicament waste, simultaneously not generating solid waste and waste gas, and having no secondary pollution; meanwhile, the catalyst does not change in chemical properties from the beginning to the end of the catalytic oxidation reaction, does not attenuate in performance, and can be repeatedly used for a long time.

Detailed Description

The invention is further illustrated by the following specific examples, which are intended to be illustrative only and not limiting.

Example 1

A catalyst for promoting the oxidation of formaldehyde in wastewater comprising: the composite material comprises silicon dioxide, manganese dioxide, nano iron, calcium sulfate and silver powder, wherein the mass ratio of the components is 1: 1.9: 2.5: 0.9: 0.006;

the preparation process comprises the following steps: (1) uniformly mixing silicon dioxide, manganese dioxide, nano iron, calcium sulfate and silver powder which are weighed according to a certain proportion, and melting at 1600 ℃; (2) cooling to 540 deg.C, injecting into mold for condensation nucleation; (3) when the surface temperature of the catalyst is reduced to 270 ℃, 10 ℃ water is splashed, the soaked water is instantly vaporized to puncture the inside of the catalyst to form holes, various fine grains can be cracked under instant cooling by utilizing different coefficients of thermal expansion and cold contraction of various components in the catalyst, and the surface area of the inside of the catalyst is provided through physical actions, so that the reaction contact area of the catalyst is increased, and solid porous catalyst particles with the average particle size of 7.6mm are obtained.

The catalyst is used for catalyzing the oxidation reaction of formaldehyde in wastewater: 1000mL of wastewater (the formaldehyde content in the wastewater is 1200mg/L, the methanol content is 1800mg/L, the glucose content is 2000mg/L, the urea content is 650mg/L, the melamine content is 2400mg/L, the phenol content is 520mg/L and the acetic acid content is 150 mg/L) is put into a 2000mL glass beaker; 1.6g of the catalyst prepared in example 1 was added, the pH of the wastewater was adjusted to 7.5, 1.6g of 27.5% hydrogen peroxide was added, and the reaction was carried out at 5 ℃ under normal atmospheric pressure for 1 hour, and then the wastewater in a beaker was taken for detection, and the results were: the formaldehyde content is 0.5mg/L, the methanol content is 1785mg/L, the glucose content is 1996mg/L, the urea content is 645mg/L, the melamine content is 2387mg/L, the phenol content is 520mg/L and the acetic acid content is 150 mg/L. The result shows that the catalyst has the best catalytic oxidation effect on formaldehyde, the removal rate reaches 99.96 percent, the catalytic oxidation on other organic matters is very little, and the removal rate is less than 1 percent. In the reaction process, formaldehyde is decomposed into carbon dioxide, so no waste gas is generated, and the waste water after the reaction is clear and no solid waste is generated.

Example 2

A catalyst for promoting the oxidation of formaldehyde in wastewater comprising: the silicon dioxide, the manganese dioxide, the nano iron, the calcium sulfate and the silver powder are as follows by mass: 1: 1.8: 2.4: 0.8: 0.005;

the preparation process comprises the following steps: (1) uniformly mixing silicon dioxide, manganese dioxide, nano iron, calcium sulfate and silver powder which are weighed according to a certain proportion, and melting at 1700 ℃; (2) cooling to 570 ℃, injecting into a mould for condensation and nucleation; (3) when the surface temperature of the catalyst is reduced to 290 ℃, 5 ℃ of water is splashed, the soaked water is instantly vaporized to puncture the inside of the catalyst to form holes, and various fine grains can be cracked under instant cooling by utilizing different coefficients of thermal expansion and cold contraction of various components in the catalyst, and the surface area in the catalyst is provided through the physical actions, so that the reaction contact area of the catalyst is increased, and the solid porous catalyst particles with the average particle size of 7.2mm are obtained.

The catalyst is used for catalyzing the oxidation reaction of formaldehyde in wastewater: 1000mL of wastewater (the content of formaldehyde in the wastewater is 5600mg/L, the content of methanol is 11000mg/L, the content of glucose is 4200mg/L, the content of urea is 1250mg/L, the content of melamine is 4600mg/L, the content of phenol is 1120mg/L, and the content of acetic acid is 2050 mg/L) is put into a 2000mL glass beaker, 9.6g of the catalyst prepared in example 2 is put into the beaker, the PH value of the wastewater is adjusted to 8.0, 8 g of hydrogen peroxide with the concentration of 27.5% is added, and the wastewater in the beaker is taken for detection after 1 hour of reaction at the temperature of 10 ℃ under normal atmospheric pressure, and the result is that: the formaldehyde content is 1.2mg/L, the methanol content is 10914mg/L, the glucose content is 4180mg/L, the urea content is 1240mg/L, the melamine content is 4556L, the phenol content is 1120mg/L, and the acetic acid content is 2050mg/L, and the result shows that the catalyst has the best catalytic oxidation effect on formaldehyde, the removal rate reaches 99.98%, the catalytic oxidation on other organic matters is very slight, and the removal rate is less than 1%. In the reaction process, formaldehyde is decomposed into carbon dioxide, so no waste gas is generated, and the waste water after the reaction is clear and no solid waste is generated.

Example 3

A catalyst for promoting the oxidation of formaldehyde in wastewater comprising: the composite material comprises silicon dioxide, manganese dioxide, nano iron, calcium sulfate and silver powder, wherein the mass ratio of the components is 1: 2: 2.6: 0.9: 0.006;

the preparation process comprises the following steps: (1) uniformly mixing silicon dioxide, manganese dioxide, nano iron, calcium sulfate and silver powder which are weighed according to a certain proportion, and melting at 1800 ℃; (2) cooling to 580 deg.C, injecting into mold for condensation and nucleation; (3) when the surface temperature of the catalyst is reduced to 300 ℃, 8 ℃ water is splashed, the soaked water is instantly vaporized to puncture the inside of the catalyst to form holes, various fine grains can be cracked under instant cooling by utilizing different coefficients of thermal expansion and cold contraction of various components inside the catalyst, and the surface area inside the catalyst is provided through physical actions, so that the reaction contact area of the catalyst is increased, and solid porous catalyst particles with the average particle size of 6.6mm are obtained.

The catalyst is used for catalyzing the oxidation reaction of formaldehyde in wastewater: 1000mL of wastewater (the formaldehyde content in the wastewater is 24000mg/L, the methanol content is 21000mg/L, the glucose content is 20000mg/L, the urea content is 4500mg/L, the melamine content is 6400mg/L, the phenol content is 5500mg/L, and the acetic acid content is 6500 mg/L) is taken and put into a 2000mL glass beaker, 45g of the catalyst prepared in the example 3 is put into the beaker, the PH value of the wastewater is adjusted to 8.5, 35g of hydrogen peroxide with the concentration of 27.5% is added, the wastewater in the beaker is taken and detected after 1 hour of reaction at the temperature of 15 ℃ and normal atmospheric pressure, and the result is that: the formaldehyde content is 2.4 mg/L, the methanol content is 20798mg/L, the glucose content is 19960mg/L, the urea content is 4458mg/L, the melamine content is 6342mg/L, the phenol content is 5490mg/L, and the acetic acid content is 6490mg/L, and the results show that the catalyst has the best catalytic oxidation effect on formaldehyde, the removal rate reaches 99.99%, the catalytic oxidation on other organic matters is very slight, and the removal rate is less than 1%. In the reaction process, formaldehyde is decomposed into carbon dioxide, so no waste gas is generated, and the waste water after the reaction is clear and no solid waste is generated.

Example 4

A catalyst for promoting the oxidation of formaldehyde in wastewater comprising: the composite material comprises silicon dioxide, manganese dioxide, nano iron, calcium sulfate and silver powder, wherein the mass ratio of the components is 1: 2: 2.6: 1: 0.008;

the preparation process comprises the following steps: (1) uniformly mixing silicon dioxide, manganese dioxide, nano iron, calcium sulfate and silver powder which are weighed according to a certain proportion, and melting at 1750 ℃; (2) cooling to 550 ℃, injecting into a mold for condensation and nucleation; (3) when the surface temperature of the catalyst is reduced to 320 ℃, 5 ℃ water is splashed, the soaked water is instantly vaporized to puncture the inside of the catalyst to form holes, and various fine grains can be cracked under instant cooling by utilizing different coefficients of thermal expansion and cold contraction of various components in the catalyst, and the surface area in the catalyst is provided through the physical actions, so that the reaction contact area of the catalyst is increased, and the solid porous catalyst particles with the average particle size of 5.7mm are obtained.

The catalyst is used for catalyzing the oxidation reaction of formaldehyde in wastewater: 1000mL of wastewater (the formaldehyde content in the wastewater is 80000mg/L, the methanol content is 25000mg/L, the glucose content is 30000mg/L, the urea content is 12000mg/L, the melamine content is 15600mg/L, the phenol content is 9600mg/L, and the acetic acid content is 15440 mg/L) is put into a 2000mL glass beaker, 170g of the catalyst prepared in example 4 is put into the beaker, the PH value of the wastewater is adjusted to 9.0, 115g of hydrogen peroxide with the concentration of 27.5% is added, the wastewater in the beaker is taken for detection after 1 hour of reaction at the temperature of 25 ℃ under normal atmospheric pressure, the formaldehyde content in the wastewater is 3.5mg/L, the methanol content is 24756mg/L, the glucose content is 29740mg/L, the urea content is 11890mg/L, the melamine content is 15456mg/L, the phenol content is 0mg/L, and the acetic acid content is 15431mg/L, the result shows that the catalyst has the best catalytic oxidation effect on formaldehyde, the removal rate reaches over 99.99 percent, the catalytic oxidation on other organic matters is very little, and the removal rate is less than 1 percent. In the reaction process, formaldehyde is decomposed into carbon dioxide, so no waste gas is generated, and the waste water after the reaction is clear and no solid waste is generated.