表面改性纳米二氧化钛-芳香聚酰胺复合反渗透膜的制备与表征

PREPARATION AND CHARACTERIZATION OF SURFACE-MODIFIED NANO-TiO_2/AROMATIC POLYAMIDE COMPOSITE REVERSE OSMOSIS MEMBRANES

采用TMC对亲水纳米TiO2进行表面改性,然后添加在复合反渗透膜的聚酰胺层中,制备了改性纳米TiO2-聚酰胺复合反渗透膜。改性纳米TiO2使用红外光谱法(FTIR)和粒径分析仪进行表征;采用渗透试验,扫描电镜(SEM)、静态接触角仪、原子力显微镜等对复合膜的性能和结构分别测试和表征。结果表明,改性TiO2的表面接枝上酰氯基团,在有机溶剂中的分散性得到提高;SEM和AFM照片证实,TiO2在膜表面分布均匀,膜表面粗糙度增加;杂化复合膜亲水性也有一定程度的提高;膜性能测试结果证实了添加TiO2的复合膜水通量均高于纯聚酰胺膜,同时脱盐率变化很小。当改性TiO2的添加量为0.05%(m/v)时,水通量由11.21 L/(m2.h)提升到32.61 L/(m2.h),对NaCl截留率达到98.9%。试验结果表明,改性TiO2很好地分散在聚酰胺层,提高了水通量,还保持了高脱盐率,膜性能得到提高。

Hydrophilic nano-TiO2 particles were surface modified with trimesoyl chloride （TMC） and then added into polyamide layer of thin film composite membranes to prepare surface-modified Nano-TiO2-polyamide composite RO membranes for desalination. The modified Nano-TiO2 were characterized by fourier transform infrared spectroscopy （FT-IR） and submicron particle size analyzer. The properties and structure of membranes were characterized by the permeation experiment, scanning electron microscopy （SEM）, contact angle measurement, and atomic force microscope （AFM）, respectively. The results showed that TiO2 were successfully surface-modified with TMC. The SEM and AFM images depicted that the modified TiO2 were well dispersed in the polyamide thin film layer and the surface of membrane was rougher thanbefore. The results of contact angle measurement indicated that the hydrophilicity of membranes was increased after addition of the nano-TiO2 into composite membranes. The RO performance results verified that the flux of the modified-TiO2 composite membranes was all higher than that of the pure polyamide membranes under the same conditions, whereas the salt rejection was improved slightly. The flux of the hybrid composite membranes with 0.05% （m/v） TiO2 loading was increased from 11.21 L/ （m2.h） to 32.61 L/ （m2.h）, while the salt rejection was increased to 98.9%. The experimental results revealed that the modified TiO： was well dispersed in the polyamide thin film layer, and hence improved the water permeation while maintaining high salt rejection.