| As an emerging technology,ultrafiltration has been widely used in water treatment industry.Ultrafiltration has the advantages of high efficiency and low energy consumption,which is more popular.However,organic membrane fouling during the ultrafiltration caused by the natural organicmatter in natural water will lead to a rapid decrease in flux,which greatly limits the further development of ultrafiltration.The combination of ion exchange resin and ultrafiltration can effectively control the formation of membrane fouling.As a pretreatment method,the ion exchange resin can effectively reduce the consistence of organic matters,thereby slowing the membrane fouling;the integrated process coupled with the ultrafiltration process,in addition to reducing the concentration of organic matter,can also form a dynamic film on the film surface,which has better anti-fouling performance than the separated process.In this experiment,sodium alginate was used to simulate the polysaccharides in natural water.The effect of the combination of powder ion exchange resin and ultrafiltration technology on membrane fouling was explored.Sodium alginate was further separated into three blocks,the contribution of different blocks to membrane fouling was investigated,and the control mechanism of powder ion exchange resin on membrane fouling was analyzed from a microscopic level.The experimental results show that the contribution of the three blocks to membrane fouling is not the same.The membrane fouling of the MM block and the GG block is mainly reversible,while the MG block causes the heaviest irreversible membrane fouling.The membrane fouling behavior of SA ultrafiltration is the result of the cross-linking of the three blocks.After the five-cycle filtration experiment,under the dosage of 5m L / L resin,the PAEX-UF integrated process has the most significant effect on membrane fouling control.Compared with the ultrafiltration alone,the increased membrane resistance is reduced by 94.1%,and decreased by 54.7% compared to the separated process.The cumulative rate of irreversible fouling in ultrafiltration SA alone is 9.24×108 m-1min-1,while the cumulative rates of irreversible fouling in the integrated processes and separated processes are 1.22×108 m-1min-1 and 3.04×108 m-1min-1,The integrated process shows better anti-fouling performance for better control of irreversible fouling.In terms of effluent quality,the DOC removal rate of the integrated process reached 93.4%,while the removal rate of the separated process was 85.1%.The analysis of the membrane fouling control mechanism shows that the MG block in SA is the main cause of irreversible fouling.After cross-linking with the remaining blocks,a higher concentration of TEP can be formed,resulting in higher reversible fouling.Compared with UF alone,the addition of PAEX can remove the SA concentration from the source,so it can have a good control effect on reversible and irreversible fouling.Compared with the separated process,the integrated process has the same degree of reducing the load of organic fouling,but in the integrated process,the resin can form a dynamic layer of particles and pollutants on the surface of the membrane after adsorbing SA.The organic matter has a higher mass transfer performance,thereby adsorbing more organic matter.The results of the microscopic interface force show that the force between PAEX and the pollutant is greater than the force between the pollutant and the membrane,so the pollutant will be more closely adsorbed on the resin surface.While in the process of hydraulic backwashing,it will separate from the membrane surface along with the resin,so as to achieve better control of membrane fouling. |
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