| With the expansion of desalination scale and the rapid development of industrialization process,the problem of concentrate seawater and wastewater treatment becomes more and more serious.This problem could be solved by nanofiltration process,and the zero liquid discharge?ZLD?aim would be achieved.In this process,the nanofiltration membranes should possess a high selectivity characteristic and a high pressure-resistant characteristic.Therefore,this article prepared different types of nanofiltration membranes by interfacial polymerization,and studied their selectivity characteristic.In addition,the article also studied the pressure-resistant characteristic by layered interfacial polymerization?LIP?process.The type of membranes prepared by piperazine?PIP?and 1,3,5-benzoyl chloride?TMC?got a better selectivity and pure water flux.And their selective coefficients were??NaCl/MgSO4?=148.96 and??NaCl/CaCl2?=13.11,respectively.Furthermore,the pure water flux of the membranes was up to 105.3 Kg/m2/h.Therefore,the PIP-TMC type of membranes were more suitable for high selective separation,and they had a higher cost-effectiveness on account of the higher pure water flux.Furthermore,a serious of PIP-TMC type membranes were prepared with different polyamide layers,based on the spin-coating LIP process.The separation performance was evaluated by different single inorganic salts solution and a kind of mixed salt solution.As a results,it showed that the selectivity characteristic increased with the polyamide layer number increased.In addition,the nanofiltration membranes were evaluated by a pressure-resistant test.It was indicated that the pressure-resistant ability increased with the layer number increased.Therefore,the spin-coating LIP can control the selectivity and pressure-resistant of membranes in a certain extent,and it can be used for preparing the composite nanofiltration membrane with high selectivity and high pressure-resistant. |
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