阅读说明：本技术 造纸废水的处理方法以及废水处理装置 (Method for treating papermaking wastewater and wastewater treatment apparatus ) 是由 俞黎萍 张玉芬 于 2021-09-27 设计创作，主要内容包括：本发明提供了一种造纸废水的处理方法以及废水处理装置。本发明的造纸废水的处理方法是将造纸废水用臭氧、双氧水和臭氧催化剂进行处理,其中,臭氧催化剂包括载体和活性组分,载体为颗粒状氧化铝,活性组分包括第一金属元素的氧化物和第二金属元素的氧化物,第一金属元素为铈,第二金属元素为铁、锰、铜、镍、锌、钛中的至少一种。根据本发明,能够有效地提高造纸废水的氧化效果。(The invention provides a method for treating papermaking wastewater and a wastewater treatment device. The papermaking wastewater treatment method comprises the step of treating the papermaking wastewater by using ozone, hydrogen peroxide and an ozone catalyst, wherein the ozone catalyst comprises a carrier and an active component, the carrier is granular alumina, the active component comprises an oxide of a first metal element and an oxide of a second metal element, the first metal element is cerium, and the second metal element is at least one of iron, manganese, copper, nickel, zinc and titanium. According to the invention, the oxidation effect of the papermaking wastewater can be effectively improved.)

1. The method for treating the papermaking wastewater is characterized in that the papermaking wastewater is treated by ozone, hydrogen peroxide and an ozone catalyst, the ozone catalyst comprises a carrier and an active component, the carrier is granular alumina, the active component comprises an oxide of a first metal element and an oxide of a second metal element, the first metal element is cerium, and the second metal element is at least one of iron, manganese, copper, nickel, zinc and titanium.

2. The method for treating paper-making wastewater according to claim 1, wherein the method for preparing the ozone catalyst comprises the steps of:

step (i): preparing a solution containing the active component;

step (ii): spray-dipping the solution on the particulate alumina;

step (iii): (iii) curing the particulate alumina treated in step (ii);

step (iv): impregnating the particulate alumina after the curing with hydrazine hydrate; and

step (v): (iv) drying and calcining the particulate alumina treated in step (iv) to obtain the ozone catalyst.

3. The method for treating paper making wastewater according to claim 1 or 2, comprising the steps of:

step (a): treating the papermaking wastewater with ozone and hydrogen peroxide; and

step (b): treating the papermaking wastewater treated in the step (a) with the ozone catalyst and ozone.

4. The method for treating papermaking wastewater according to claim 3, wherein in the step (a), the molar ratio of hydrogen peroxide to ozone is 0.5 to 1.5.

5. The method for treating papermaking wastewater according to claim 3, wherein in the step (b), the liquid hourly space velocity is 14h^-1The following.

6. The method for treating paper-making waste water according to claim 1 or 2, wherein the contaminants in the paper-making waste water include 2, 4-di-tert-butylphenol and/or 2,2' -methylenebis (4-methyl-6-tert-butylphenol).

7. The utility model provides a wastewater treatment device (10), characterized in that, wastewater treatment device (10) includes hydrogen peroxide solution introduction part (13), ozone generator (15) and connect in hydrogen peroxide solution introduction part (13) with ozone reactor (17) of ozone generator (15), be provided with the ozone catalyst in ozone reactor (17), the ozone catalyst includes carrier and active component, the carrier is granular alumina, the active component includes the oxide of first metallic element and the oxide of second metallic element, first metallic element is cerium, the second metallic element is at least one of iron, manganese, copper, nickel, zinc, titanium.

8. The wastewater treatment plant (10) according to claim 7, characterized in that the method of preparing the ozone catalyst comprises the steps of:

step (i): preparing a solution containing the active component;

step (ii): spray-dipping the solution on the particulate alumina;

step (iii): (iii) curing the particulate alumina treated in step (ii);

step (iv): impregnating the particulate alumina after the curing with hydrazine hydrate; and

step (v): (iv) drying and calcining the particulate alumina treated in step (iv) to obtain the ozone catalyst.

9. The wastewater treatment apparatus (10) according to claim 7 or 8, wherein the ozone reactor (17) includes a primary ozone reactor (171) connected to the hydrogen peroxide solution introduction part (13) and the ozone generator (15), and a secondary ozone reactor (172) connected to a water outlet of the primary ozone reactor (171), and the ozone catalyst is provided in the secondary ozone reactor (172).

10. The wastewater treatment apparatus (10) according to claim 7 or 8, characterized in that the wastewater treatment apparatus (10) further comprises a wastewater pretreatment section comprising a buffer tank (12) for homogenizing the quality of wastewater and a sand filtration tank (14) connected to an outlet of the buffer tank (12) and for removing suspended matter in wastewater,

the discharge hole of the hydrogen peroxide introduction part (13) is connected with a flow path between the water outlet of the buffer tank (12) and the water inlet of the sand filter tank (14), and the water outlet of the sand filter tank (14) is connected with the water inlet of the ozone reactor (17).

Technical Field

The invention relates to the field of wastewater treatment, in particular to a method for treating papermaking wastewater and a wastewater treatment device.

Background

At present, the domestic wastewater treatment process of large and medium-sized pulping and papermaking plants mainly comprises primary physical and chemical treatment, secondary biochemical treatment and tertiary Fenton (Fenton) chemical oxidation treatment. In the whole production process of the paper industry, waste water and waste liquid are generated in each workshop section and each workshop section, and the fluctuation of the quality and the quantity of the waste water and the pollution load is large due to the fact that the water consumption of the paper industry is dense and the quality and the condition of the waste water in different workshop sections are different. Therefore, a proper wastewater treatment process is selected according to actual conditions, the wastewater treatment cost is further reduced, a new technology for reducing the generation amount of solid wastes in the wastewater treatment process and energy utilization of the solid wastes is developed, technical support is provided for the engineering application of the subsequent reclaimed water recycling technology, and the method is a development direction in the future.

In addition, the supply of waste paper in paper mills is greatly changed under the influence of national environmental protection policies. Particularly, imported waste paper is constantly reduced, domestic waste paper use amount is constantly increased, and partial substitute fiber raw materials (such as wood flour and wood fiber) are used, so that the sewage components discharged by the paper machine are greatly changed, more pollutants which cannot be decomposed or are difficult to decompose are mixed in sewage, and the original sewage treatment system is difficult to meet the COD discharge standard requirement after upgrading and modification. In this regard, attention has been focused on advanced oxidation technologies for treating wastewater. At present, most of paper mills adopt Fenton oxidation as the tertiary treatment of paper-making wastewater, and certain effect is achieved. However, the Fenton oxidation technique has many disadvantages such as a long treatment reaction time, and a large amount of metallic iron ions and SO remaining in the treatment solution₄ ^2-Causing iron sludge pollution. Therefore, in order to fundamentally get rid of the problems of iron sludge pollution and disposal in fenton water treatment, it is urgently needed to develop a more environment-friendly treatment process.

Ozone can be rapidly degraded into oxygen in the air, the problem of ozone residue can be avoided, and the production cost can be effectively reduced. Therefore, the ozone catalytic oxidation treatment method is suitable for treating the organic matters which are difficult to biodegrade in the wastewater after the secondary biochemical treatment by adopting the ozone catalytic oxidation.

However, the papermaking wastewater does not have typical characteristic pollutants, and the organic components of the papermaking wastewater are very complex. For example, as shown by analyzing and detecting the paper-making wastewater of a certain paper mill by using a gas chromatography-mass spectrometer (GC-MS), several contaminants with relatively high content in the paper-making wastewater of a certain paper mill are respectively phenolic antioxidants, alkanoic acids, olefins, fatty amines, aniline and the like, and the total content of the contaminants is only 55%. Therefore, the effect of treating the papermaking wastewater by using the existing ozone-hydrogen peroxide process is not ideal.

Disclosure of Invention

In order to solve one or more of the above-mentioned problems occurring in the prior art, the present invention provides a method for treating paper-making wastewater and a wastewater treatment apparatus.

The method for treating the papermaking wastewater is a method for treating the papermaking wastewater by using ozone, hydrogen peroxide and an ozone catalyst, wherein the ozone catalyst comprises a carrier and an active component, the carrier is granular alumina, the active component comprises an oxide of a first metal element and an oxide of a second metal element, the first metal element is cerium, and the second metal element is at least one of iron, manganese, copper, nickel, zinc and titanium. The method for treating the papermaking wastewater adopts the novel ozone catalyst to treat the papermaking wastewater, and can effectively improve the oxidation effect of the papermaking wastewater. Among them, by providing the carrier of the ozone catalyst in the form of particles, it is possible to overcome the problems that the carrier in the form of powder is easily lost and cannot be applied to a process, as compared with the conventional carrier in the form of powder.

The preparation method of the ozone catalyst used in the treatment method of the papermaking wastewater can comprise the following steps: step (i): preparing a solution containing an active ingredient; step (ii): spraying and soaking the solution on granular alumina; step (iii): (iii) curing the particulate alumina treated in step (ii); step (iv): impregnating the cultured granular alumina with hydrazine hydrate; and step (v): and (iv) drying and roasting the granular alumina treated in the step (iv) to obtain the ozone catalyst. Hydrazine hydrate is introduced in the second step of impregnation in the preparation method of the ozone catalyst, so that the grain size of the active components is reduced, the number of the active components is increased, the active sites are more protruded, the activity of the ozone catalyst can be greatly improved, and the oxidation effect of the treatment method of the papermaking wastewater is improved.

The treatment method of the papermaking wastewater comprises the following steps: step (a): treating papermaking wastewater with ozone and hydrogen peroxide; and a step (b): treating the papermaking wastewater treated in the step (a) with an ozone catalyst and ozone. The COD treatment effect of the papermaking wastewater is better and the impact resistance is stronger by carrying out ozone-hydrogen peroxide treatment and then carrying out ozone catalyst-ozone treatment.

Wherein, in the step (a), the molar ratio of the hydrogen peroxide to the ozone is 0.5-1.5. By setting the molar ratio of hydrogen peroxide to ozone in step (a) within this range, the COD treatment effect of the papermaking wastewater can be further improved.

Wherein, in the step (b), the liquid hourly space velocity is 14h^-1The following. The liquid hourly space velocity of the method for treating papermaking wastewater reaches up to 14h^-1And the treatment cost can be greatly reduced.

Wherein the pollutants in the papermaking wastewater comprise 2, 4-di-tert-butylphenol and/or 2,2' -methylenebis (4-methyl-6-tert-butylphenol).

The invention also provides a wastewater treatment device, which comprises a hydrogen peroxide introduction part, an ozone generator and an ozone reactor connected with the hydrogen peroxide introduction part and the ozone generator, and is characterized in that an ozone catalyst is arranged in the ozone reactor, the ozone catalyst comprises a carrier and an active component, the carrier is granular alumina, the active component comprises an oxide of a first metal element and an oxide of a second metal element, the first metal element is cerium, and the second metal element is at least one of iron, manganese, copper, nickel, zinc and titanium. The waste water treatment device provided by the invention is used for treating the papermaking waste water, and the oxidation effect of the papermaking waste water can be effectively improved. Among them, by providing the carrier of the ozone catalyst in the form of particles, it is possible to overcome the problems that the carrier in the form of powder is easily lost and cannot be applied to a process, as compared with the conventional carrier in the form of powder.

The preparation method of the ozone catalyst comprises the following steps: step (i): preparing a solution containing an active ingredient; step (ii): spraying and soaking the solution on granular alumina; step (iii): (iii) curing the particulate alumina treated in step (ii); step (iv): impregnating the cultured granular alumina with hydrazine hydrate; and step (v): and (iv) drying and roasting the granular alumina treated in the step (iv) to obtain the ozone catalyst. Hydrazine hydrate is introduced in the second step of impregnation in the preparation method of the ozone catalyst, so that the grain size of the active components is reduced, the number of the active components is increased, the active sites are more protruded, the activity of the ozone catalyst can be greatly improved, and the performance of a wastewater treatment device is improved.

Wherein, the ozone reactor comprises a primary ozone reactor connected with the hydrogen peroxide leading-in part and the ozone generator and a secondary ozone reactor connected with the water outlet of the primary ozone reactor, and the ozone catalyst is arranged in the secondary ozone reactor. Therefore, by utilizing the wastewater treatment device, the COD treatment effect of the papermaking wastewater is better and the impact resistance is stronger by firstly carrying out ozone-hydrogen peroxide treatment and then carrying out ozone catalyst-ozone treatment.

Wherein, waste water treatment facilities still includes waste water preliminary treatment portion, and waste water preliminary treatment portion is connected and is used for getting rid of the sand filtration jar of the suspended solid in the waste water including the buffer tank that is used for the quality of water of even waste water and the delivery port with the buffer tank, and the discharge gate of hydrogen peroxide solution leading-in portion is connected in the flow path between the delivery port of buffer tank and the water inlet of sand filtration jar, and the delivery port of sand filtration jar is connected in ozone reactor's water inlet. Thus, the wastewater treatment effect can be improved by pretreating the wastewater.

Drawings

The above and other objects and features of the present invention will become more apparent from the following description of the embodiments taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic view showing the construction of a wastewater treatment apparatus of the present invention.

FIG. 2 is a schematic view showing the structure of still another wastewater treatment apparatus according to the present invention.

Description of the symbols

10 a wastewater treatment plant;

11 a tail gas destroyer;

12 a buffer tank;

13 a hydrogen peroxide introduction part;

14, a sand filter tank;

15 an ozone generator;

16 an ejector;

17 an ozone reactor;

171 a primary ozone reactor;

172 two-stage ozone reactor

Detailed Description

The inventors of the present invention have found that a novel ozone catalyst having excellent catalytic performance can be obtained by using cerium as a metal in combination with at least one of transition metals such as iron, manganese, copper, nickel, zinc, and titanium as an active component of the ozone catalyst. It is presumed that this is due to the fact that the redox reaction is essentially a process of electron gain and loss, and the transition metal exists in a plurality of valence states, such as iron oxide (Fe)²⁺/Fe³⁺) Manganese oxide (Mn)²⁺/Mn³⁺And Mn³⁺/Mn⁴⁺) Copper oxide (Cu)⁺And Cu²⁺) Nickel oxide (Ni)²⁺/Ni³⁺) Zinc oxide (Zn)⁺/Zn²⁺) Titanium oxide (Ti)³⁺/Ti⁴⁺) The multi-valence metal ions have different valence conversion modes in the oxidation-reduction reaction process, so that the transfer of electrons is better promoted, the electron transfer in the catalytic oxidation process of ozone can be enhanced, and the catalytic oxidation capacity of ozone is enhanced. Further, it has been found that the novel ozone catalyst is particularly excellent in the effect of treating papermaking wastewater with a very complicated organic component in the ozone-hydrogen peroxide process. The present invention has been accomplished based on this finding.

Specifically, the method for treating the papermaking wastewater is a method for treating the papermaking wastewater by using ozone, hydrogen peroxide and an ozone catalyst, wherein the ozone catalyst comprises a carrier and an active component, the carrier is granular alumina, the active component comprises an oxide of a first metal element and an oxide of a second metal element, the first metal element is cerium, and the second metal element is at least one of iron, manganese, copper, nickel, zinc and titanium.

The carrier of the ozone catalyst used in the method for treating paper-making wastewater of the present invention is in the form of particles. Through the design, compared with the prior powder carrier, the problems that the powder carrier is easy to run off and cannot be applied in engineering can be overcome. Wherein, the carrier is preferably spherical alumina with the diameter of 3-6mm or strip alumina with the diameter of 3-5mm and the length of 5-20 mm. By limiting the size of the carrier within the above range, the load efficiency of the carrier can be effectively improved to the maximum extent under the condition of satisfying engineering application.

In addition, the ozone catalyst used in the method for treating paper-making wastewater of the present invention can improve the excellent oxidation effect on paper-making wastewater by using the first metal element and the second metal element in combination. However, the inventors have further found that an ozone catalyst having particularly excellent performance can be obtained if the molar ratio of the first metal element to the second metal element is set in the range of 1:2 to 1: 4.

In addition, the second metal element is preferably manganese. By using a specific combination of cerium and manganese as an active component, the performance of the ozone catalyst can be further significantly improved as compared with a combination of cerium and another transition metal as an active component.

In addition, the mass ratio of the particulate alumina to the active component may be appropriately selected as needed. However, an excessively high amount of the particulate alumina relative to the active component may result in an excessively small amount of the active component supported by the particulate alumina per unit area, affecting the catalytic efficiency of the ozone catalyst; too low an amount of the particulate alumina relative to the active component leads to unnecessary waste of the active component and an increase in production cost. Therefore, the mass ratio of the particulate alumina to the active component is preferably 50:1 to 5: 1.

In addition, the method for preparing the ozone catalyst used in the method for treating paper-making wastewater of the present invention preferably comprises the steps of: step (i): preparing a solution containing an active ingredient; step (ii): spraying and soaking the solution on granular alumina; step (iii): (iii) curing the particulate alumina treated in step (ii); step (iv): impregnating the cultured granular alumina with hydrazine hydrate; and step (v): and (iv) drying and roasting the granular alumina treated in the step (iv) to obtain the ozone catalyst. Hydrazine hydrate is introduced in the second step of impregnation in the preparation method of the ozone catalyst, so that the grain size of the active components is reduced, the number of the active components is increased, the active sites are more protruded, the activity of the ozone catalyst can be greatly improved, and the effect of the treatment method of the papermaking wastewater is improved. In particular, the capability of oxidizing two antioxidant organic matters, namely 2, 4-di-tert-butylphenol and 2,2' -methylene-bis (4-methyl-6-tert-butylphenol), which are characteristic pollutants in papermaking wastewater is greatly improved.

The amount of hydrazine hydrate may be appropriately selected as needed. Preferably, the molar amount of hydrazine hydrate is 1 to 10 times the molar amount of the active component.

In addition, in step (i), it is preferable to prepare a solution by dissolving cerium nitrate and a nitrate of the second metal element in water. In the case that the raw material of the active component is mainly nitrate, the nitrate can generate NOx during the roasting process to pollute the environment. And the salt generated by the reaction of hydrazine hydrate and the precursor of the active component can not generate NOx in the roasting process, thereby avoiding environmental pollution.

The curing time in the step (iii) and the drying temperature, drying time, firing temperature and firing time in the step (v) may be appropriately set as required. Preferably, in the step (iii), the curing time is 4 to 10 hours. Preferably, in step (v), after drying at 100-150 ℃ for 3-10 hours, the material is calcined at 300-800 ℃ for 2-8 hours.

In addition, the method for treating papermaking wastewater of the present invention preferably comprises the steps of: step (a): treating papermaking wastewater with ozone and hydrogen peroxide; and a step (b): treating the papermaking wastewater treated in the step (a) with an ozone catalyst and ozone. The COD treatment effect of the papermaking wastewater is better and the impact resistance is stronger by carrying out ozone-hydrogen peroxide treatment and then carrying out ozone catalyst-ozone treatment.

Wherein, the mol ratio of the hydrogen peroxide to the ozone in the step (a) is preferably 0.5-1.5. It is particularly preferred that the molar ratio of hydrogen peroxide to ozone in step (a) is 0.5. By setting the molar ratio of hydrogen peroxide to ozone in step (a) within this range, the COD treatment effect of the papermaking wastewater can be further improved.

Wherein the liquid hourly space velocity in step (b) can reach 14h at most^-1Thus, the processing cost can be greatly reduced. This is because the liquid hourly space velocity is defined as the volume of wastewater treated per hour per unit volume of catalyst, and therefore the amount of water treated and the amount of ozone catalyst added determine the liquid hourly space velocity. And under the same condition, the lower the liquid hourly space velocity is, the better the treatment effect is. In the case of ensuring the COD removal effect, setting a higher liquid hourly space velocity means that the shorter the oxidation reaction time, the less the amount of ozone catalyst used, i.e., the lower the investment cost, for the same amount of treated water. In the method for treating papermaking wastewater of the present invention, the liquid hourly space velocity in step (b) is preferably 2h^-1Above and 14h^-1Hereinafter, more preferably 4 hours^-1Above and 14h^-1Hereinafter, 8h is particularly preferable^-1Above and 14h^-1The following.

In addition, the invention also provides a wastewater treatment device which comprises a hydrogen peroxide introduction part, an ozone generator and an ozone reactor which is connected with the hydrogen peroxide introduction part and the ozone generator and is provided with the novel ozone catalyst. The waste water treatment device provided by the invention is used for treating the papermaking waste water, and the oxidation effect of the papermaking waste water can be effectively improved.

Wherein, the optimized ozone reactor comprises a primary ozone reactor connected with the hydrogen peroxide leading-in part and the ozone generator and a secondary ozone reactor connected with the water outlet of the primary ozone reactor, and the ozone catalyst is arranged in the secondary ozone reactor. Therefore, by utilizing the wastewater treatment device, the COD treatment effect of the papermaking wastewater is better and the impact resistance is stronger by firstly carrying out ozone-hydrogen peroxide treatment and then carrying out ozone catalyst-ozone treatment.

Wherein, preferred effluent treatment plant still includes waste water preliminary treatment portion, and waste water preliminary treatment portion is connected and is used for getting rid of the sand filtration jar of the suspended solid in the waste water including the buffer tank that is used for the quality of water of even waste water and the delivery port with the buffer tank, and the discharge gate of hydrogen peroxide solution leading-in portion is connected in the flow path between the delivery port of buffer tank and the water inlet of sand filtration jar, and the delivery port of sand filtration jar is connected in ozone reactor's water inlet. Thus, the wastewater treatment effect can be improved by pretreating the wastewater.

The technical solution of the present invention is described in detail below by examples, but the scope of the present invention is not limited to the examples.

First, the following ozone catalysts of the present invention were prepared for use.

1. The ozone catalyst of the present invention having cerium and manganese as active components (hereinafter also referred to as ozone catalyst a) was prepared according to the following procedure.

Step (i): 16.3kg of manganese nitrate (wherein, the manganese element is 91mol), 7.5kg of cerium nitrate (wherein, the cerium element is 23mol) and 250kg of spherical alumina with the diameter of 3-5mm are weighed. Manganese nitrate and cerium nitrate were dissolved in 145L of deionized water to prepare solution A.

Step (ii): the solution A was spray-soaked on spherical alumina for 2 hours.

Step (iii): and (5) curing for 4 hours.

Step (iv): weighing 8kg of hydrazine hydrate, pouring the hydrazine hydrate into spherical alumina, diluting the hydrazine hydrate with deionized water until the liquid surface is just lack of aluminum peroxide, uniformly stirring, and filtering after 10 hours.

Step (v): after drying at 100 ℃ for 10 hours, it was calcined at 300 ℃ for 8 hours.

Thereby, the ozone catalyst a of the present invention was obtained.

2. The ozone catalyst of the present invention having cerium and iron as active components (hereinafter also referred to as ozone catalyst b) was prepared according to the following procedure.

Step (i): 180kg of iron nitrate (wherein the iron element is 744mol), 74.5kg of cerium nitrate (wherein the cerium element is 228mol) and 250kg of spherical alumina with the thickness of 3-5mm are weighed. Iron nitrate and cerium nitrate were dissolved in 145L of deionized water to prepare solution A.

Step (ii): the solution A was spray-soaked on spherical alumina for 2 hours.

Step (iii): and (5) preserving for 10 hours.

Step (iv): weighing 80kg of hydrazine hydrate, pouring the hydrazine hydrate into spherical alumina, diluting the hydrazine hydrate with deionized water until the liquid surface just exceeds the spherical alumina, uniformly stirring, and filtering after 10 hours.

Step (v): after drying at 150 ℃ for 2 hours, it was calcined at 800 ℃ for 2 hours.

Thereby, the ozone catalyst b of the present invention was obtained.

3. The ozone catalyst of the present invention having cerium and copper as active components (hereinafter also referred to as ozone catalyst c) was prepared according to the following procedure.

Step (i): 18.9kg of copper nitrate (wherein the copper element is 101mol), 14.9kg of cerium nitrate (wherein the cerium element is 46mol) and 250kg of spherical alumina of 3-5mm were weighed. Copper nitrate and cerium nitrate were dissolved in 145L of deionized water to prepare solution A.

Step (ii): the solution A was spray-soaked on spherical alumina for 2 hours.

Step (iii): and (5) preserving for 6 hours.

Step (iv): 31.8kg of hydrazine hydrate is weighed and poured into spherical alumina, then the hydrazine hydrate is diluted by deionized water until the liquid surface just passes through the spherical alumina, then the mixture is stirred uniformly and filtered after 10 hours.

Step (v): after drying at 120 ℃ for 4 hours, the mixture was calcined at 500 ℃ for 4 hours.

Thereby, the ozone catalyst c of the present invention was obtained.

4. The ozone catalyst of the present invention having cerium and nickel as active components (hereinafter also referred to as ozone catalyst d) was prepared according to the following procedure.

Step (i): 50kg of nickel nitrate (in which 274mol of nickel element is contained), 30kg of cerium nitrate (in which 92mol of cerium element is contained), and 300kg of 3-5mm spherical alumina were weighed. Nickel nitrate and cerium nitrate were dissolved in 145L of deionized water to prepare solution A.

Step (ii): the solution A was spray-soaked on spherical alumina for 2 hours.

Step (iii): and (5) preserving for 5 hours.

Step (iv): weighing 50kg of hydrazine hydrate, pouring the hydrazine hydrate into spherical alumina, diluting the hydrazine hydrate with deionized water until the liquid surface just passes through the spherical alumina, uniformly stirring, and filtering after 10 hours.

Step (v): after drying at 120 ℃ for 6 hours, it was calcined at 600 ℃ for 3 hours.

Thereby, the ozone catalyst d of the present invention was obtained.

Example 1

FIG. 1 shows the structure of a wastewater treatment apparatus 10 according to example 1 of the present invention. As shown in fig. 1, the wastewater treatment apparatus 10 includes an exhaust gas destruction device 11, a buffer tank 12, a hydrogen peroxide solution introduction part 13, a sand filtration tank 14, an ozone generator 15, an ejector 16, and an ozone reactor 17 filled with the prepared 140L ozone catalyst a. Among them, the buffer tank 12 and the sand filtration tank 14 constitute a wastewater pretreatment section of the present invention. Specifically, the outlet of the buffer tank 12 is connected to the inlet of the sand filter tank 14, and the outlet of the hydrogen peroxide solution introduction unit 13 is connected between the outlet of the buffer tank 12 and the inlet of the sand filter tank 14, and supplies hydrogen peroxide solution to the flow path. In addition, the water outlet of the sand filter tank 14 is connected with the water inlet of the ejector 16, the air outlet of the ozone generator 15 is connected with the air inlet of the ejector 16, and the water outlet of the ejector 16 is connected with the water inlet of the ozone reactor 17. The air outlet of the ozone reactor 17 is connected with the air inlet of the tail gas destructor 11.

The wastewater treatment apparatus 10 of fig. 1 is used to perform the treatment method of the present invention for treating paper-making wastewater by using an ozone catalyst-ozone-hydrogen peroxide solution process.

Specifically, after the paper making wastewater to be treated is uniform in water quality in the buffer tank 12, the paper making wastewater enters the sand filtration tank 14 from the buffer tank 12, suspended matters (SS) in the paper making wastewater in the sand filtration tank 14 are effectively removed, then the paper making wastewater enters the reactor 17 from the sand filtration tank 14 through the ejector 16 connected with the ozone generator 15 for oxidation reaction, and the generated tail gas is introduced into the tail gas destructor 11 for treatment. In this embodiment, the ozone reactor 17 used is a stainless steel column reactor having an inner diameter of 0.6m, a total height of 2m, and an effective height of 1 m. The ejector 16 functions to better achieve gas-water mixing to improve the solubility of ozone by generating micro-bubbles. The gas source of the ozone generator 15 is an oxygen cylinder.

Namely, the process flow of the wastewater treatment apparatus 10 is: water quality is uniformed in the surge tank 12 → suspended matter (SS) in the paper making wastewater is removed in the sand filtration tank 14 → the paper making wastewater is sufficiently mixed with ozone by the ejector 16 → oxidation is performed in the ozone reactor 17 → water is discharged.

Specifically, the amount of ozone added was 77 g/ton of water (77mg/L), wherein the ozone concentration was 120mg/L and the ozone intake amount was 1.26m³/h。

The formula for calculating the ozone adding amount is as follows:

the adding amount of the hydrogen peroxide added into the reaction system by the hydrogen peroxide introducing part 13 is H₂O₂And O₃The optimum molar ratio is determined to be 0.5. The amount of ozone added was 77 g/ton of water, that is, the amount of ozone added was 1.6 mol/ton of water. Therefore, the optimal adding amount of the hydrogen peroxide is 0.8 mol/ton of water, namely the optimal adding amount of the hydrogen peroxide is 27 g/ton of water.

The amount of treated water was set to 47m³/d(1.96m³1960L/h), namely the liquid hourly space velocity is 14h^-1。

The results of treating the papermaking wastewater by the wastewater treatment apparatus 10 are shown in table 1.

Comparative example 1

The process flow and process parameters were the same as in example 1, except that the hydrogen peroxide introduction part 13 was not provided, that is, hydrogen peroxide was not added to the reaction system. The results of the papermaking wastewater treated by this process are shown in table 1 as comparative example 1.

Comparative example 2

The process flow and process parameters were the same as in example 1 except that the ozone catalyst of the present invention was not filled in the ozone reactor 17 at all. The results of the papermaking wastewater treated by this process are shown in table 1 as comparative example 2.

Thus, the results of the performance evaluation tests of examples and comparative examples are shown in table 1:

TABLE 1 comparison of the treatment effects of papermaking wastewater

The antioxidant 1 is 2, 4-di-tert-butylphenol (structural formula:)

the antioxidant 2 is 2,2' -methylene bis (4-methyl-6-tert-butylphenol) (structural formula:)

the symbol "-" before the corresponding numeral indicates an increase

As can be seen from table 1, different kinds of organic substances are oxidized to different degrees by catalysis, among which aniline, alkanoic acids, amides and alkanols are easily oxidized, while other kinds of organic substances are oxidized to different degrees. However, the macroscopic removal rate of COD was the best achieved using example 1, and the amount of ozone added per mg of COD removed in this example was 1.4 mg. GB/T39308-containing 2020 advanced treatment technical Specification for refractory organic wastewater specifically states that the ozone catalytic oxidation method is used for treating COD per mg_crThe dosage of the ozone is 1mg-10 mg', namely the dosage of the ozone for removing each milligram of COD is 1mg-10 mg. This indicates that the ozone dosage using the present invention is very low, i.e., the running cost is very low. Therefore, the method for treating papermaking wastewater and the corresponding wastewater treatment device have excellent effect of treating papermaking wastewater.

Example 2

FIG. 2 shows the structure of a wastewater treatment apparatus 10 according to example 2 of the present invention. As shown in FIG. 2, the waste water treatment apparatus 10 of example 2 is different in that a primary ozone reactor 171 and a secondary ozone reactor 172 connected to the primary ozone reactor 171 are used in place of the reactor 17. Specifically, the water outlet of the jet device 16 is connected to the water inlet of the primary ozone reactor 171, the water outlet of the primary ozone reactor 171 is connected to the water inlet of the secondary ozone reactor 172, and the water outlet of the secondary ozone reactor 172 is connected to the air inlet of the tail gas destructor 11. Then, the prepared 140L of ozone catalyst a was filled in the secondary ozone reactor 172. In this embodiment, the primary ozone reactor 171 is a cylindrical reactor made of PVC having an inner diameter of 0.2m, an overall height of 2.3m and an effective height of 2m, and the secondary ozone reactor 172 is a cylindrical reactor made of stainless steel having an inner diameter of 0.6m, an overall height of 2m and an effective height of 1 m.

The method for treating paper-making wastewater using the combined process of ozone-hydrogen peroxide and ozone catalyst-ozone according to the present invention was performed using the wastewater treatment apparatus 10 of fig. 2.

Specifically, the gas-water mixture from the ejector 16 is first subjected to ozone-hydrogen peroxide treatment in the primary ozone reactor 171, then subjected to ozone catalyst-ozone treatment in the secondary ozone reactor 172, and finally the resulting exhaust gas is passed to the exhaust gas destructor 11 for treatment.

Wherein the treated water amount is 47m³/d(1.96m³1960L/h). The dosage of ozone is 91 g/ton water (91mg/L), wherein the ozone concentration is 120mg/L, and the ozone gas intake is 1.49m³/h。

The dosage of hydrogen peroxide in the primary ozone reactor 171 is as follows: h₂O₂And O₃The optimum molar ratio is 0.5. The amount of ozone added was 91 g/ton of water, that is, the amount of ozone added was 1.9 mol/ton of water. Therefore, the optimal adding amount of the hydrogen peroxide is 0.95 mol/ton of water, namely the optimal adding amount of the hydrogen peroxide is 32 g/ton of water.

The loading of the ozone catalyst in the secondary ozone reactor 172 is 140L, namely the liquid hourly space velocity is 14h^-1。

The removal rates of 2, 4-di-tert-butylphenol and 2,2' -methylenebis (4-methyl-6-tert-butylphenol), which are characteristic contaminants in papermaking wastewater, and COD are shown in table 2.

TABLE 2 comparison of the treatment effects of papermaking wastewater in different processes

The antioxidant 1 is 2, 4-di-tert-butylphenol (structural formula:)

the antioxidant 2 is 2,2' -methylene bis (4-methyl-6-tert-butylphenol) (structural formula:)

the symbol "-" before the corresponding numeral indicates an increase

In the corresponding form, the term "alone" means not detected

As can be seen from Table 1, the characteristic contaminants in the papermaking wastewater were fatty amine, aniline, 2, 4-di-t-butylphenol, alkanoic acid and 2,2' -methylenebis (4-methyl-6-t-butylphenol), in which the fatty amine, aniline and alkanoic acid were easily oxidized. In the three treatment processes of ozone catalyst-ozone-hydrogen peroxide (example 1), ozone catalyst-ozone (comparative example 1) and ozone-hydrogen peroxide (comparative example 2), although the macroscopic COD removal rate of the ozone catalyst-ozone-hydrogen peroxide process is the highest (55%), most of 2, 4-di-tert-butylphenol undergoes dimerization reaction during the treatment process to generate 2,2' -methylenebis (4-methyl-6-tert-butylphenol). But the ozone catalyst-ozone process has better removal effect on both antioxidants. To O₃-H₂O₂In the process, although a small amount of 2, 4-di-tert-butylphenol is subjected to dimerization reaction to generate 2,2' -methylenebis (4-methyl-6-tert-butylphenol), the ozone-hydrogen peroxide process has the best effect on treating the 2, 4-di-tert-butylphenol and has better macroscopic COD removal rate. In conclusion, the preliminary judgment: mixing ozone-hydrogen peroxide and ozone catalyst-ozoneThe two processes of oxygen are combined for use, the COD removal effect is probably best, and most of 2, 4-di-tert-butylphenol is oxidized in the first process of ozone-hydrogen peroxide treatment; in the second stage process of ozone catalyst-ozone treatment, a considerable part of two antioxidants can be oxidized, so that the COD removal rate of the combined process is obviously improved. And the amount of ozone added to the combined process to remove each mg of COD was 1.4 mg. GB/T39308-containing 2020 advanced treatment technical Specification for refractory organic wastewater specifically states that the ozone catalytic oxidation method is used for treating COD per mg_crThe dosage of the ozone is 1mg-10 mg', namely the dosage of the ozone for removing each milligram of COD is 1mg-10 mg. This indicates that the ozone dosage of the present application is very low, i.e., the running cost is very low.

As can be seen from Table 2 above, it is generally difficult to oxidize the characteristic contaminants 2, 4-di-tert-butylphenol and 2,2' -methylenebis (4-methyl-6-tert-butylphenol) in papermaking wastewater. However, when the ozone catalyst is used in the combined process of ozone-hydrogen peroxide and ozone catalyst-ozone, the capability of oxidizing characteristic pollutants 2, 4-di-tert-butylphenol and 2,2' -methylenebis (4-methyl-6-tert-butylphenol) in papermaking wastewater is greatly improved. This is because, in the ozone catalyst used in the present application, hydrazine hydrate is introduced in the second impregnation step during the preparation process, so that the grain size of the active component is reduced, thereby increasing the amount of the active component, and also making the active site more prominent, thereby greatly improving the activity of the ozone catalyst, and thus improving the ability of oxidizing two antioxidant organic substances, i.e., 2, 4-di-tert-butylphenol and 2,2' -methylenebis (4-methyl-6-tert-butylphenol).

Comparison of Effect with respect to different ozone catalysts

Using the wastewater treatment apparatus 10 of example 1, 140L of the prepared 140L ozone catalysts a-d were charged into the ozone reactor 17, respectively, and the treatment effects of the ozone catalysts a-d on the papermaking wastewater were compared by using the same process flow and process parameters as those of example 1. The results are shown in Table 3.

TABLE 3 COD removal Rate of each ozone catalyst

As can be seen from table 3, the ozone catalyst having a combination of cerium and manganese as an active component has the highest average COD removal rate and the best effect, compared to the ozone catalyst having a combination of cerium and another transition metal as an active component.

Comparison of Effect with different molar ratios of Hydrogen peroxide to ozone

The wastewater treatment apparatus 10 of example 2 was used to compare the treatment effects of papermaking wastewater using hydrogen peroxide and ozone at different molar ratios according to the same process flow and process parameters as those of example 2, except that the molar ratio of hydrogen peroxide to ozone in the primary ozone reactor 171 was changed. The results are shown in Table 4.

TABLE 4 COD removal Rate for different hydrogen peroxide to ozone molar ratios

Molar ratio of hydrogen peroxide to ozone	COD removal Rate (%)
		0.5	65
1.5	58
		1.0	60
0.75	63

As is clear from table 4, the molar ratio of hydrogen peroxide to ozone in the primary ozone reactor 171 is set within the range of 1.5 to 0.5, whereby the COD treatment effect of the paper making wastewater can be further improved. Wherein the best effect is achieved when the molar ratio of the hydrogen peroxide to the ozone is 0.5.

It should be noted that the papermaking wastewater used in the above tests was obtained from the effluent of a secondary sedimentation tank of a sewage treatment plant in a certain paper mill of Dongguan, Guangdong province, and the COD content thereof was 100 mg/L.

In summary, the ozone catalyst and the preparation method of the ozone catalyst provided by the invention have the following beneficial effects:

(1) the invention applies the novel ozone catalyst which takes the combination of cerium and transition metal as active components to the ozone-hydrogen peroxide process, and has particularly excellent oxidation effect on the papermaking wastewater. In addition, by providing the carrier of the ozone catalyst in the form of particles, it is possible to overcome the problem that the carrier in the form of powder is easily lost and cannot be applied to a process, as compared with the carrier in the form of powder in the past. In addition, the size of the carrier is limited to the above range, so that the loading efficiency of the carrier can be effectively improved to the maximum extent under the condition of meeting the engineering application.

(2) Aiming at the defect that the effect of treating the papermaking wastewater by adopting an ozone-hydrogen peroxide process in the prior art is not ideal, a customized ozone catalytic oxidation technology is provided according to characteristic pollutants in the papermaking wastewater, and the COD treatment effect is better and the impact resistance is stronger by combining the ozone-hydrogen peroxide process and the ozone catalyst-ozone process.

(3) The liquid hourly space velocity of the invention can reach 14h at most^-1. Because the relationship between the liquid hourly space velocity and the oxidation reaction time is:

when the liquid hourly space velocity is 14h^-1When the temperature of the water is higher than the set temperature,

therefore, the oxidation reaction time of the present application can be reduced to 4.3 min. The shorter the oxidation reaction time, the less catalyst is used, i.e. the lower the investment cost, for the same amount of water treated.

(4) In the preparation process of the ozone catalyst, hydrazine hydrate is introduced in the second step of impregnation, so that the grain size of the active component is reduced, the number of the active component is increased, and the active site is more protruded, thereby greatly improving the activity of the ozone catalyst, and particularly improving the capability of characteristic pollutants in paper-making wastewater to oxidize two antioxidant organic matters, namely 2, 4-di-tert-butylphenol and 2,2' -methylenebis (4-methyl-6-tert-butylphenol). In addition, in the case where the raw material of the active component is mainly nitrate, the nitrate may generate NOx during the firing process to pollute the environment. And the salt generated by the reaction of hydrazine hydrate and the precursor of the active component can not generate NOx in the roasting process, thereby avoiding environmental pollution.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention; it is intended that the following claims be interpreted as including all such alterations, modifications, and equivalents as fall within the true spirit and scope of the invention.