Study on Nanofiltration Desalination and Separation for NaCl/Na2SO4 Mixed Salt Solutions
In order to explore the desalination and mass separation effect of nanofiltration technology in industrial high salt wastewater treatment,the nanofiltration membrane VNF1-4040 was used to study the desalination and separation process for NaCl and Na2SO4 mixed salt solutions.The influence of membrane flux,feed concentration and feed temperature on the desalination effect of nanofiltration with different mass concentration ratios was investigated.The results show that the nanofiltration membrane always has the better removal effect on Na2SO4 under the investigated conditions,and the rejection rate of Na2SO4 is higher than 97.5%.When the mass ratio of NaCl/Na2SO4 is 1∶9,it gets the best rejection rate of Na2SO4 compared with other mass ratio in the same environmental conditions.Lower membrane flux,higher feed concentration and feed temperature can lead to the better NaCl rejection rate,which means better desalination effect.When the membrane flux,feed concentration and feed temperature are 26 LMH,2 g/L and 10℃,the rejection rate of Na2SO4 reaches its peak being 98.41%,98.24%and 98.80%,respectively.In this experiment,nanofiltration membrane has a good separation effect on NaCl,and the proportion of NaCl concentration in the produced water remains above 96%.
nanofiltration membranehigh salt wastewaterNaCl/Na2SO4 mixed saltdesalination and separationnega-tive intercept
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