10 advanced technologies in the water treatment industry

At present, the magnetization technology mainly includes magnetic agglomeration technology, ferric salt co-sedimentation technology, iron powder method, ferrite method, etc. The representative magnetic separation equipment is disk magnetic separator and high gradient magnetic filter. At present, magnetic separation technology is still in the laboratory research stage and can not be applied to practical engineering practice.

6. Ionized water treatment technology

Low temperature plasma water treatment technology, including high voltage pulse discharge plasma water treatment technology and glow discharge plasma water treatment technology, is the use of discharge directly in the aqueous solution to generate plasma, or the active particles in the gas discharge plasma into the water, which can make the pollutants in the water completely oxidized and decomposed.

The direct pulse discharge in aqueous solution can be operated at normal temperature and pressure, and the chemical oxidizing species in situ can be oxidized and degraded organic matter in aqueous solution without adding catalyst during the whole discharge process. This technology is economical and effective for the treatment of low concentration organic matter. In addition, the type of reactor using pulsed discharge plasma water treatment technology can be flexibly adjusted, the operation process is simple, and the corresponding maintenance cost is low. Due to the limitation of discharge equipment, the energy efficiency of this process to degrade organic matter is low, and the application of plasma technology in water treatment is still in the research and development stage.

7. Electrochemical (catalytic) oxidation

Electrochemical (catalytic) oxidation technology directly degrades organic matter through anodic reaction, or generates hydroxyl radical (˙OH), ozone and other oxidants to degrade organic matter through anodic reaction.

Electrochemical (catalytic) oxidation includes two - and three-dimensional electrode systems. Due to the micro-electric field electrolysis of three-dimensional electrode system, it has been highly respected. The three-dimensional electrode is filled with granular or other detritus working electrode material between the electrodes of the traditional two-dimensional electrolytic cell, and the surface of the loaded material is charged to become the third pole, and the electrochemical reaction can occur on the surface of the working electrode material.

Compared with the two-dimensional flat electrode, the three-dimensional electrode has a large specific surface, can increase the surface ratio of the electrolyzer, can provide a larger current intensity at a lower current density, small particle spacing and high mass transfer speed, high space-time conversion efficiency, so the current efficiency is high and the processing effect is good. Three-dimensional electrodes can be used to treat domestic sewage, pesticides, dyes, pharmaceuticals, phenolic wastewater and other difficult to degrade organic wastewater, metal ions, landfill leachate and so on.

8. Radiation technology

Since the 1970s, with the development of large-scale cobalt sources and electron accelerator technology, the radiation source problem in the application of radiation technology has been gradually improved. The use of radiation technology to treat pollutants in wastewater has attracted the attention of many countries.

Compared with traditional chemical oxidation, the use of radiation technology to treat pollutants does not need to add or only a small amount of chemical reagents, does not produce secondary pollution, has the advantages of high degradation efficiency, fast reaction speed, and thorough degradation of pollutants. Moreover, when ionizing radiation is used in combination with catalytic oxidation means such as oxygen and ozone, a "synergistic effect" will be produced. Therefore, radiation technology to deal with pollutants is a clean and sustainable technology, which is listed as the main research direction of peaceful use of atomic energy in the 21st century by the International Atomic Energy Agency.

9. Photochemical catalytic oxidation

Photochemical catalytic oxidation technology is developed on the basis of photochemical oxidation, compared with photochemical method, has a stronger oxidation capacity, can make organic pollutants more thoroughly degraded. Photochemical catalytic oxidation is a photochemical degradation in the presence of catalysts, and the oxidant produces free radicals with strong oxidation capacity under the radiation of light.

The catalysts are TiO2, ZnO, WO3, CdS, ZnS, SnO2 and Fe3O4. Homogeneous photocatalytic degradation is based on Fe2+ or Fe3+ and H2O2 as the medium, and hydroxyl free radicals are produced by photoassisted Fenton reaction to degrade pollutants. Heterogeneous catalytic degradation is to put a certain amount of photosensitive semiconductor materials in the pollution system, such as TiO2, ZnO, and so on, combined with light radiation, so that the photosensitive semiconductor under light irradiation excitation to produce electron-hole pairs, dissolved oxygen, water molecules adsorb on the semiconductor and electron-hole interaction, resulting in ˙OH and other strong oxidation capacity of free radicals. TiO2 photocatalytic oxidation technology has obvious advantages in oxidizing and degrading organic pollutants in water, especially difficult to degrade organic pollutants.