CN107021583B

CN107021583B - Porous titanium ozone aerator with ozone heterogeneous catalysis-electrocatalysis function

Info

Publication number: CN107021583B
Application number: CN201610071158.7A
Authority: CN
Inventors: 李新洋; 郑建中; 刘桂成
Original assignee: University of Chinese Academy of Sciences
Current assignee: University of Chinese Academy of Sciences
Priority date: 2016-02-02
Filing date: 2016-02-02
Publication date: 2021-06-04
Anticipated expiration: 2036-02-02
Also published as: CN107021583A

Abstract

A porous titanium ozone aerator with the functions of ozone heterogeneous catalysis and electrocatalysis. The ozone aerator is composed of a porous titanium substrate and a catalytic layer loaded on the substrate. The catalyst layer is oxides of Ti, Mn, Ce, Cu, Fe, Ni, Sn, Sb, Pb and the like or a composite of the metal oxides, and the oxide morphology can be nanoflower, nanowire, nanorod and nanotube. The porous titanium aerator is endowed with the cooperative catalytic capability of ozone heterogeneous catalysis and electrocatalytic oxidation, so that the high-efficiency catalytic reaction of three phases of gas, solid and liquid in the aerator of pollutants can be achieved, and the aims of efficiently mineralizing and removing the target pollutants are fulfilled. The porous titanium ozone aerator is used for drinking water treatment, wastewater treatment and other occasions using ozone, has the characteristics of strong oxidation capacity, high reaction speed, stable treatment effect, long service life, low investment, wide application range and the like, and has good application prospect.

Description

Porous titanium ozone aerator with ozone heterogeneous catalysis-electrocatalysis function

The invention relates to a porous titanium ozone aerator with ozone heterogeneous catalysis-electrocatalysis functions, in particular to a porous titanium ozone aerator which is loaded with a catalytic coating and has the ozone heterogeneous catalysis-electrocatalysis functions. The gas-liquid-solid three-phase catalytic reaction can be effectively realized on the surface of the porous titanium aerator through the synergistic catalytic effect of the catalyst, and the decomposition of target pollutants in the wastewater is promoted. The invention belongs to the technical field of ozone aerators in water treatment processes.

Background

Ozone has been widely used in the fields of sterilization, decolorization, degradation of organic substances, deodorization, and the like. In addition, the ozone mainly carries out direct oxidation reaction in the treatment process of the target pollutants, wherein the direct reaction generally means that the ozone directly reacts with organic matters, and the method has stronger selectivity and is generally more effective on unsaturated aliphatic hydrocarbon and aromatic hydrocarbon compounds, so that the method is more effective on bond breaking, ring opening and decomposition of the pollutants such as organic pollutants, but has no remarkable mineralization effect on the organic pollutants. Therefore, a certain amount of metal oxide (TixO) is added into the ozone system_y、Mn_xO_y、Cu_xO_y、Ce_xO_yEtc.) to catalyze ozone to generate oxidant hydroxyl free radical with stronger oxidation capacity, and mineralize organic matter without selectivity, so as to realize ozone oxidation process-heterogeneous ozone catalytic oxidation technology for strengthening pollutant mineralization and removal. Compared with the traditional ozone oxidation, the technology has the characteristics of strong oxidation capability, complete pollutant mineralization degree and the like. To the skillIn terms of the technique, the catalysts usually used are in the form of powders or granules (supported on a particulate support such as activated carbon or alumina). Ozone is introduced into a fluidized bed or a fixed bed filled with the catalyst through an aerator, and organic pollutants are subjected to gas, solid and liquid three-phase catalytic oxidation reaction on the surface of the catalyst and are mineralized and decomposed. But powder or particle supported catalysts are all present: 1) the powder catalyst is difficult to recover and has large loss, and 2) the particle catalyst is easy to rub and pulverize mutually. Importantly, the ozone is difficult to reach the uniform diffusion of the ozone and target pollutants on the surface of the particle catalyst in the packed bed of the particle-supported catalyst, especially in the stacking bed, the mass transfer resistance is large, and the effective utilization rate of the catalyst is reduced. In addition, the commonly used ozone aerator is made of inorganic sand stone, stainless steel and other materials, but has the problems of poor oxidation resistance, poor acid and alkali resistance, easy seepage of residual substances and ions, secondary pollution and the like.

In recent years, porous titanium, which has excellent characteristics of corrosion resistance, oxidation resistance, acid and alkali resistance, safety, no secondary pollution and the like, is gradually used as an ozone aerator in processes of using ozone, such as chemical production, drinking water and wastewater treatment, food processing and the like. According to the requirement of the size of aeration bubbles, the porous titanium aerator can be customized according to different pore size specifications, so that the application flexibility is strong, and the application range is wide. In particular, the porous titanium material is an ideal catalyst support material in view of its excellent three-dimensional porous structure and high specific surface area. Therefore, the porous titanium aerator is used as a carrier, and the double-effect catalyst with ozone heterogeneous catalysis and electrocatalysis is loaded on the porous titanium aerator, so that the three-dimensional, continuous and porous structure of the porous titanium can be fully exerted, more bearing area can be provided for the construction of an active layer, the catalytic activity and the degradation efficiency of target pollutants are promoted to be improved, meanwhile, the self flow type configuration and the pore channel effect of the porous titanium promote the gas and liquid to be fully transferred on a catalytic layer on the surface of the porous titanium by virtue of forced convection, and the high-efficiency gas, solid and liquid three-phase catalytic reaction efficiency is achieved. Meanwhile, the loaded ozone-electrocatalyst is tightly combined with the porous titanium and also has a three-dimensional porous structure, so that the problems of loss of the powder catalyst, pulverization of the particle catalyst, poor mass transfer and the like are effectively solved.

Although a related patent CN202465355U has reported a porous titanium ozone aerator, the focus is to improve the aeration effect of ozone by improving the configuration of the shape and to enhance the pressure resistance of the aerator. The research on endowing the porous titanium aerator with certain catalytic capability, particularly ozone heterogeneous catalysis and electrocatalytic capability has not been reported yet.

Disclosure of Invention

The invention aims to provide a porous titanium ozone aerator with ozone heterogeneous catalysis-electrocatalysis functions, and the porous titanium aerator is endowed with the ozone heterogeneous catalysis and electrocatalysis functions at the same time. In addition, the three-dimensional, continuous and porous structure of the porous titanium is fully utilized to provide more bearing area for the construction of the catalyst, and the improvement of catalytic activity and the degradation efficiency of target pollutants is promoted. Meanwhile, the self-circulation configuration and the channel effect of the porous titanium promote the gas and liquid to fully transfer mass on the catalyst layer on the surface of the porous titanium under the action of forced convection, so that the high-efficiency gas, solid and liquid three-phase catalytic reaction efficiency is achieved, and the high-efficiency mineralization and removal of target pollutants are realized. The loaded ozone-electrocatalyst is tightly combined with the porous titanium and has a three-dimensional porous structure, so that the problems of loss of the powder catalyst, poor mass transfer and the like can be effectively solved.

The technical scheme of the invention is as follows:

a porous titanium ozone aerator with ozone heterogeneous catalysis-electrocatalysis functions is characterized in that the ozone aerator is composed of a porous titanium substrate and a catalysis layer loaded on the substrate. The catalyst layer is oxides of Ti, Mn, Ce, Cu, Fe, Ni, Sn, Sb, Pb and the like or a composite of the metal oxides, and the catalyst layer can be in the shape of nanospheres, nanowires, nanorods and nanotubes.

The invention relates to a porous titanium ozone aerator with ozone heterogeneous catalysis-electrocatalysis functions, which is characterized in that: the ozone aerator is flat, tubular and spherical porous titanium, and the average pore size range is 2-200 mu m.

The loading method of the catalyst layer of the porous titanium ozone aerator with the ozone heterogeneous catalysis-electrocatalysis function comprises a hydrothermal method, an alcohol heating method, an anodic oxidation method, a dipping method-sintering method, a sol-gel method thermal decomposition method and an electrodeposition method.

Drawings

FIG. 1 is a schematic diagram of an ozone catalytic-electrocatalytic oxidation reaction device of a porous titanium ozone aerator

FIG. 2 is a SEM photograph of example 2.

FIG. 3 is a SEM photograph of example 3.

Detailed Description

Example 1: the porous titanium ozone aerator with the ozone heterogeneous catalysis-electrocatalysis function selects tubular porous titanium with the average pore diameter of 55 mu m as a substrate, and loads TiO by a hydrothermal method₂A catalytic layer on the porous titanium substrate, wherein the TiO₂The appearance of the nano flower array.

Example 2: the porous titanium ozone aerator with the ozone heterogeneous catalysis-electrocatalysis function selects tubular porous titanium with the average pore diameter of 45 mu m as a substrate, and MnO is loaded by a hydrothermal method₂A catalytic layer on the porous titanium substrate, wherein MnO is₂The appearance of the nano-rod array is formed.

Example 3: the porous titanium ozone aerator with the ozone heterogeneous catalysis-electrocatalysis function selects tubular porous titanium with the average pore diameter of 50 mu m as a substrate, and loads TiO by a hydrothermal method-sol gel method₂-SnO₂A composite catalytic layer on the porous titanium substrate, wherein the TiO₂-SnO₂The appearance of the composite catalyst layer forms a nanoflower array.

Example 4: the ozone catalysis-electrochemical oxidation effect test of the porous titanium ozone aerator with the ozone heterogeneous catalysis-electrocatalysis function is carried out in the embodiment. The porous titanium ozone aerators prepared in examples 1-3 were placed in a glass reactor for electrolytic tests (COD: 1000 mg/L, pH = 3) for treating rhodamine B dye, in which the electrolyte Na was₂SO₄The concentration was 0.1M. The porous titanium ozone aerator is used as an anode, and the platinum electrode is used as a cathode. In the test, the current density of 15 is applied to the porous titanium ozone aeratormA/cm²8 mg/L ozone gas was simultaneously applied to the reaction solution at a constant current, the reaction was carried out for 2.5 hours, and the COD removal rate was measured as an evaluation index.

Table 1 effect of porous titanium ozone aerator prepared in the example of the present invention on removing contaminants

Examples	1	2	3
				COD average removal rate (%)	81%	95%	99%

As can be seen from the table 1, the porous titanium ozone aerator with the ozone heterogeneous catalysis-electrocatalysis function has higher removal rate of organic pollutant rhodamine B in an ozone-electrocatalysis oxidation test and has excellent catalytic effect.

Claims

1. A porous titanium ozone aerator with ozone heterogeneous catalysis-electrocatalysis function is characterized in that the ozone aerator is composed of a porous titanium substrate and a catalysis layer loaded on the substrate;

the catalyst layer is Ti, Mn, Ce, Cu, Fe, Ni, Sn, Sb, Pb oxides or a composite of the metal oxides, and the catalyst layer is in the shape of nanospheres, nanowires, nanorods and nanotubes;

the ozone aerator is flat, tubular and spherical porous titanium, and the average pore size range is 2-200 mu m;

the loading method of the catalyst layer comprises a hydrothermal method, an alcohol heating method, an anodic oxidation method, a dipping method-sintering method, a sol-gel method thermal decomposition method and an electrodeposition method.