With the progress of science and technology, membrane separation technology is becoming more and more mature and its application scope is expanding. Among them, it is the most widely used in environmental engineering, which can effectively improve the effect of environmental pollution control and prevention. This paper discusses the specific application of various membrane separation technologies in environmental engineering.
Key words: membrane separation technology; Environmental engineering; App application
According to the separation process, membrane separation technology includes many types, such as microfiltration, ultrafiltration and nanofiltration. Through membrane separation technology, solid and gas pollutants in the environment can be effectively treated, which can prevent these pollutants from polluting the environment and improve the cleanliness of the environment. The purpose of environmental engineering is to alleviate the present situation of environmental pollution, prevent the aggravation of environmental pollution and improve environmental quality. After the application of membrane separation technology, it can effectively improve the effect of engineering development and achieve the purpose of improving environmental quality.
Application of 1. microfiltration technology in environmental engineering
When the particle size of particles, bacteria and other substances is 0. 1 ~ 10 1 μm, microfiltration technology is suitable for filtration. This technology belongs to screen filtration. The operating pressure is relatively low, and it can better adapt to liquids, so it is widely used in drinking water treatment projects. In the traditional filtration technology, it is necessary to install clarification filtration and secondary sedimentation tank in the filtration tank, which occupies a large area. However, after the application of microfiltration technology, clarification filtration and secondary sedimentation tank can be directly cancelled, which effectively reduces the area of the filtration tank, and the filtration treatment effect is still good under the condition of large water quality fluctuation. In addition, through membrane separation technology, wastewater can be well treated and closed cycle can be realized. The treated sewage can be recycled again, which saves water resources and improves the utilization efficiency of resources. At the same time, it can also effectively enhance environmental awareness.
Second, the application of ultrafiltration technology in environmental engineering
The filtration pore size of ultrafiltration membrane is very small, the minimum is 0.05nm and the maximum is 1nm. In environmental engineering, after the application of ultrafiltration technology, solid particles and suspended solids contained in substances can be effectively filtered and removed. At the same time, ultrafiltration technology can also be applied to the filtration of macromolecules and colloids with good filtration effect. Ultrafiltration technology is widely used in the treatment of electrophoretic paint wastewater. Through this membrane separation technology, metal ion impurities in wastewater can be effectively removed, the recycling of wastewater can be realized, the recycling efficiency of wastewater can be improved, and the biodegradability of wastewater regeneration can be significantly enhanced. It should be noted that in the application of ultrafiltration technology in environmental engineering, the flux of ultrafiltration membrane and its corresponding components is relatively large, and its high temperature resistance and oxidation resistance are very good. The current level of ultrafiltration technology can not effectively meet this requirement, and further research and development efforts are needed to achieve this goal.
Third, the application of reverse osmosis technology in environmental engineering
No matter what solute it is, reverse osmosis membrane has very high removal rate and very high effluent quality. In general, reverse osmosis technology is often used in desalination projects. At present, reverse osmosis technology has been widely used in the field of environmental protection, mainly in four aspects: one is to improve the quality of urban drinking water, the other is to treat urban sewage, the third is to treat industrial wastewater, and the fourth is to treat landfill leachate. In landfill leachate, the concentrations of ammonia nitrogen, alkalinity and heavy metals are very high, and when the concentration of ammonia nitrogen is very high, it will have great toxic and side effects. When the activated sludge method is used to treat landfill leachate, the treatment effect is very poor, while the reverse osmosis technology can significantly improve the treatment effect. At present, when reverse osmosis technology is applied in environmental engineering, there are still some problems, mainly in two aspects, one is membrane pollution, and the other is concentration polarization. In the future research, the key point is to develop pollution-resistant and low-cost membrane materials, so that the newly developed membrane materials have high temperature resistance, oxidation resistance and ultra-low pressure performance.
Fourth, the application of nanofiltration technology in environmental engineering
In 1980s, a typical reverse osmosis composite membrane appeared, and then, after further research and development, a new membrane separation technology-nanofiltration technology was developed, which is a molecular technology and located between ultrafiltration technology and reverse osmosis technology. The filtration process of nanofiltration technology is pressure-driven. In the process of operation, when the pressure is set, the minimum setting is usually 0.5MPa and the maximum setting is l.OMPa. Ion selectivity is a prominent feature of nanofiltration membrane. When removing divalent ions, the removal rate can exceed 95%, but when removing monovalent ions, the removal rate is only between 40% and 800/0. Based on the characteristics and removal rate of nanofiltration technology, it has been widely used in the removal of harmful substances in river water and groundwater and the decoloration of wastewater. Under low pressure, the flux of nanofiltration membrane is relatively high, and compared with reverse osmosis membrane, it only needs less investment and operation expenses. However, in the process of nanofiltration, nanofiltration membrane is more susceptible to pollution, and the influent quality is relatively high during pretreatment, and the treatment process is more complicated, which limits the application of nanofiltration technology to a certain extent.
Verb (abbreviation of verb) Application of liquid membrane technology in environmental engineering
The so-called liquid film means that emulsion particles are suspended in the liquid, and the emulsion particle layer is very thin. In the process of membrane separation, osmosis has certain selectivity, and pollutants in it are extracted and adsorbed through chemical reaction to realize purification. Compared with solid membrane, liquid membrane has faster mass transfer speed, higher selectivity and separation efficiency. In solution, if ions and organic matter are separated, this technology is suitable for membrane separation. At present, liquid membrane separation technology has been well applied in the fields of medicine and chemical industry, hydrometallurgy and wastewater treatment, and the wastewater can be reused after resource treatment.
Conclusion of intransitive verbs
In environmental engineering, the application of membrane separation technology can effectively reduce the pollution of wastewater, waste gas and solid particles to the environment, realize the recycling of wastewater and effectively enhance the environmental protection effect.
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