反渗透膜前阻垢预处理工艺研究

Study on pretreatment process of scale inhibition to reverse osmosis membrane

反渗透(RO)处理工艺是当前高矿化度矿井水处理技术中应用最为广泛的一种处理方法,但膜污染问题一直制约着反渗透工艺的进一步发展。针对高矿化度矿井水反渗透处理过程中膜面易发生结垢污染,导致反渗透膜产水效率和使用寿命下降的问题,通过模拟配置高矿化度矿井水,采用全循环实验法,分别考察阻垢剂预处理与电子阻垢仪预处理对反渗透膜结垢污染的控制效果与运行成本,并对不同预处理条件下所得膜片截面SEM进行分析。实验结果表明,在无预处理条件下,采用反渗透工艺对模拟高矿化度矿井水配水进行处理,反渗透膜可发生严重的结垢污染,运行17 h后膜片截面厚度(133μm)明显高于清洁膜片厚度(115μm)。采用阻垢剂和电子阻垢仪进行反渗透膜前预处理,均会对反渗透膜结垢污染起到较好的控制效果,并且脱盐率均在90%以上。相较于电子阻垢仪预处理,采用阻垢剂进行预处理,反渗透膜结垢程度污染程度最轻,运行17 h后,膜通量仅衰减18.74%,且膜片截面厚度(118μm)更接近清洁膜片截面厚度(115μm)。但当采用阻垢剂进行膜前预处理时,反渗透设备停机后,若未对反渗透膜进行清洗,阻垢剂可残留在膜表面进而影响膜分离性能。而采用电子阻垢仪进行预处理,则反渗透膜分离性能几乎不受设备停机的影响,且其吨水运行成本明显低于阻垢剂预处理。

Reverse osmosis(RO)process is the most widely used method in the treatment of high mineralized mine water,but membrane fouling has been restricting the further development of RO process.During the RO treatment of high mineralized mine water,the scale pollution is easy to occur on membrane surface,which leads to the decrease of water production efficiency and service life of RO membrane.In this work,the control effects and operating cost of scale inhibitor pretreatment and electronic scale inhibitor apparatus pretreatment on RO membrane scaling were investigated respectively by simulating the component of high mineralized mine water and using the full cycle experiment method.And the SEM of RO membrane cross section under different pretreatment conditions was analyzed.The results showed that when the RO process was used to treat the simulated high mineralized mine water solution under the condition of no pretreatment,the RO membrane could be seriously polluted by scaling,and the membrane cross section thickness could reach 133μm that was significantly higher than clean membrane cross section thickness(115μm)after 17 hours.Using scale inhibitor and electronic scale inhibitor apparatus for pretreatment,the scale pollution of RO membrane could be well controlled,and the desalination rate was all above 90%.Compared with the electronic scale inhibitor apparatus pretreatment,the scale pollution degree of RO membrane was the lightest under the condition of scale inhibitor pretreatment.After 17 hours,the membrane flux was only decreased by 18.74%,and the membrane cross section thickness(118μm)was closer to that clean membrane cross section thickness(115μm).However,when the scale inhibitor was used for pretreatment,if the RO membrane was not cleaned after the RO equipment shut down,the scale inhibitor could remain on the mem-brane surface and affect the membrane separation performance.When electronic scale inhibitor apparatus was used for pretreatment,the separation performance of RO membrane was hardly affected by equipment shut down,and the operating cost per ton of water was signi-ficantly lower than that of scale inhibitor pretreatment.