纳滤膜对浓海水中溴离子的截留影响研究

Bromide Ion Retention of Concentrated Seawater Nanofiltration

采用国产纳滤膜N40、N70对海水淡化浓海水中溴离子的截留行为进行研究,考察不同的运行通量、回收率、温度、运行方式对纳滤分离过程中溴离子透过率的影响。结果显示:纳滤膜对离子的截留顺序为SO_(4)^(2-)>Mg^(2+)>Ca^(2+)>F^(-)>Cl^(-)>Br^(-);N70纳滤膜对溴离子具有高的透过率,N40纳滤膜对溴离子无截留作用,但其对浓海水的软化作用和脱盐效果较N70差。溴离子透过率随运行通量增加先降低后趋缓,而水回收率对溴离子截留的影响较小;溴离子透过率随温度升高而增加,且恒通量运行时相比恒压力运行条件下透过率增加更为明显;恒通量运行且温度为35℃时,N70纳滤膜对溴离子的透过率为95.3%。

Domestic N40 and N70 nanofiltration membranes were adopted to study bromide ion rejection of concentrated seawater,and the influence of operating flux,water recovery and influent temperature were investigated.The results show that the order of ion retention was SO_(4)^(2-)>Mg^(2+)>Ca^(2+)>F^(-)>Cl^(-)>Br^(-)for NF membranes.N70 membrane had high permeation for bromide ion and N40 membrane presented no rejection for bromide ion,but the seawater softening and demineralization effect of N40 is lower than N70.The permeation rate of bromide ion decreased initially and then slowed down with the rising of operating flux.The water recovery has little effect on the retention of bromide ion,while bromide permeation rate increased with the growth of temperature,and the increase was more obvious during constant flux operation mode than constant pressure operation mode.The bromide ion permeation rate of N70 was 95.3%with constant flux operation mode at 35˚C.