CN-122006469-A - Catalytic removal method of chlorinated volatile organic compound

Abstract

The invention provides a catalytic removal method of chlorinated volatile organic compounds. The catalytic removal method comprises the steps of carrying out catalytic removal on reaction gas by adopting a gas-solid phase electrocatalytic reaction, wherein the reaction gas comprises chlorinated volatile organic compounds, and a working electrode of the gas-solid phase electrocatalytic reaction comprises a Pd composite titanium dioxide electrode. The invention adopts the gas-solid phase electrocatalytic reaction to catalyze and remove the chlorinated volatile organic compounds, so that the gas pollutants can directly reach the surface of the electrode, thereby effectively bypassing the bottleneck of the gas-liquid mass transfer link, obviously improving the mass transfer and treatment efficiency and improving the catalysis effect.

Inventors

• ZHANG CHANGBIN
• HE XIAOTING
• QIAN WEIMING
• QIN XIAOXIAO
• CHEN XUEYAN

Assignees

• 郑州大学
• 中国科学院生态环境研究中心

Dates

Publication Date

20260512

Application Date

20260407

Claims (10)

1. 1. A catalytic removal process for chlorinated volatile organic compounds, characterized in that it comprises: The reaction gas is catalyzed and removed by adopting a gas-solid phase electrocatalytic reaction; The reaction gas comprises a chlorinated volatile organic compound, and the working electrode of the gas-solid phase electrocatalytic reaction comprises a Pd-composite titanium dioxide electrode.
2. 2. The catalytic removal method according to claim 1, wherein the volume concentration of the chlorinated volatile organic compound in the reaction gas is 10ppm to 5000ppm.
3. 3. The catalytic removal process according to claim 1 or 2, wherein the reaction gas further comprises oxygen and an equilibrium gas, the equilibrium gas comprising a protective gas; Preferably, the volume concentration of oxygen in the reaction gas is less than or equal to 4%.
4. 4. The catalytic removal method according to claim 1 or 2, wherein the flow rate of the reaction gas is 15mL/min to 50mL/min.
5. 5. The catalytic removal process according to claim 1, wherein in the Pd-composited titania electrode, pd is supported in the titania electrode, and the Pd loading is 0.1mg/cm 2 ~2mg/cm 2 .
6. 6. The catalytic removal method according to claim 1 or 5, wherein the method of preparing a Pd-composited titania electrode comprises: Carrying out liquid phase mixing on Pd salt and a titanium dioxide electrode, depositing a load, and then carrying out annealing treatment in a reducing atmosphere to obtain the Pd composite titanium dioxide electrode; Preferably, the preparation method of the titanium dioxide electrode comprises a hydrothermal re-sintering method; Preferably, the temperature of the annealing treatment is 200-450 ℃.
7. 7. The catalytic removal method of claim 1, wherein the gas-solid phase electrocatalytic reaction further comprises a counter electrode and an intermediate conductive layer, the intermediate conductive layer being located between the working electrode and the counter electrode.
8. 8. The catalytic removal process of claim 7, wherein the counter electrode is subjected to a water circulation treatment for recovering catalyzed chloride ions.
9. 9. The catalytic removal method according to claim 1, wherein the gas-solid phase electrocatalytic reaction has a current density of 5mA/cm 2 ~30mA/cm 2 , a voltage of-2V to-5V, and a temperature of 20 ℃ to 30 ℃; Preferably, the environmental humidity of the reaction environment in the gas-solid phase electrocatalytic reaction is 0% -80%.
10. 10. The catalytic removal method of chlorinated volatile organic compounds as claimed in claim 1, wherein the catalytic removal method comprises: And (3) introducing the reaction gas containing the chlorinated volatile organic compound into the Pd-composite titanium dioxide electrode, performing electrocatalytic removal in a gas-solid phase contact mode, and recovering chloride ions obtained by catalytic removal through the middle conductive layer into the opposite electrode terminal in a water circulation mode at the opposite electrode terminal.

Description

Catalytic removal method of chlorinated volatile organic compound Technical Field The invention belongs to the technical field of catalytic removal of volatile organic compounds, and relates to a catalytic removal method of chlorinated volatile organic compounds. Background Chlorinated volatile organic compounds (Cl-VOCs) are an important class of Volatile Organic Compounds (VOCs), widely exist in the industries of chemical industry, medicine, electronics and the like, and have large emission in the environment and extremely high toxicity. Cl-VOCs are not only easy to stay in the atmosphere and water environment, but also extremely easy to migrate and accumulate organisms, and form serious threat to the ecological system and human health. For example, part of Cl-VOCs have strong carcinogenicity, mutagenicity and teratogenicity, can induce various chronic diseases of respiratory system, nervous system and the like, can participate in photochemical reaction at the same time, promote the formation of ozone and haze, and further exacerbate environmental pollution. Therefore, achieving efficient control of such gaseous pollutants is of great environmental and public health importance. At present, although a certain progress is made in the aspect of Cl-VOCs removal by various methods such as adsorption, membrane separation, combustion, catalytic oxidation and biological treatment, the problems of low treatment efficiency, severe operation conditions, high running cost and the like of the technology generally exist, and development of a more efficient and cost-controllable treatment process is needed. Because the difficult degradation of chlorinated volatile organic compounds is the combined effect of structural stability, low bioavailability, environmental persistence, high toxicity and technical limitations, the treatment core is high-efficiency dechlorination, namely the toxicity is reduced and the biodegradability is improved by breaking C-Cl bonds, but the key scientific problems of high reaction energy barrier, selective control and the like are needed to be overcome. The existing electrocatalytic dechlorination technology can reduce Cl-VOCs into harmless chloride ions under the action of an external electric field, so that effective purification is realized, however, the electrocatalytic technology is still in a starting stage in the field of Cl-VOCs pollution treatment, and the main obstacle is that the mass transfer efficiency of the Cl-VOCs is extremely low. The efficient mass transfer process is a precondition for achieving effective removal of Cl-VOCs. In general, gaseous Cl-VOCs need to be dissolved in solution before being diffused to the electrode surface, but because they generally have strong hydrophobicity, the gas-liquid mass transfer process is limited and the efficiency is low. Therefore, how to realize the effective catalytic removal of the chlorinated volatile organic compounds (Cl-VOCs) and improve the catalytic efficiency is a technical problem to be solved urgently. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide a catalytic removal method of chlorinated volatile organic compounds. The invention adopts the gas-solid phase electrocatalytic reaction to catalyze and remove the chlorinated volatile organic compounds, so that the gas pollutants can directly reach the surface of the electrode, thereby effectively bypassing the bottleneck of the gas-liquid mass transfer link, obviously improving the mass transfer and treatment efficiency and improving the catalysis effect. In order to achieve the aim of the invention, the invention adopts the following technical scheme: The invention provides a catalytic removal method of chlorinated volatile organic compounds, which comprises the following steps: The reaction gas is catalyzed and removed by adopting a gas-solid phase electrocatalytic reaction; The reaction gas comprises a chlorinated volatile organic compound, and the working electrode of the gas-solid phase electrocatalytic reaction comprises a Pd-composite titanium dioxide electrode. When the conventional electrocatalytic removal is adopted for the chloro volatile organic compounds (Cl-VOCs), the chloro volatile organic compounds are required to be dissolved in the solution of the electrode and then diffused into the electrode, the mass transfer process seriously affects the removal efficiency, and the Cl-VOCs have higher hydrophobicity and extremely poor solubility, so that the catalytic effect is greatly reduced, and the catalytic removal effect is seriously affected. In this regard, the invention adopts the electrocatalytic method of a gas-solid phase system to carry out the catalytic removal of Cl-VOCs, the Cl-VOCs directly reach the surface of a Pd (palladium) composite titanium dioxide working electrode in a gaseous state, the bottleneck of a gas-liquid mass transfer link is bypassed, the mass transfer effect is improved, the Pd cat