膜上荷电量对超滤膜的渗透性和牛血清蛋白透过率影响的研究

改变化学反应时间获取一系列荷电量不同的改性再生纤维素(RC)超滤膜,定量地考察了超滤膜上荷电量对膜的渗透性和牛血清蛋白(BSA)透过率的影响.研究结果表明:反电渗透现象造成荷电量不同的超滤膜上的水透过系数均减小,减小的程度与膜的荷电量和溶液离子强度有关;溶液pH值为7.0的条件下,荷负电的BSA与荷负电改性RC膜之间的静电相互作用,使BSA的透过率减小,减小的程度同样与膜的荷电量和溶液离子强度有关.研究结果提供了荷电量对超滤膜渗透性和BSA透过率影响的定量数据;揭示了相对于传统超滤膜而言,荷电超滤膜具有更好的渗透性和分离选择性相结合的优势.     

粉末活性炭导入超滤系统去除水中天然有机物的性能研究

通过对比研究单独超滤系统和粉末活性炭导入超滤膜系统(PAC leading-in UF)发现,投加PAC后通量下降趋势有所减缓,但并不能显著地减缓膜污染并获得高通量,说明PAC吸附的溶解性小分子有机物不是造成膜污染的主要因素,而是在膜表面形成了"次级膜".试验中发现导入系统可显著提高对天然水中腐殖酸的去除效果,去除率可达到94%.此外在导入系统投加钙盐后可明显改善膜污染,达到有效控制膜通量的下降趋势的目的.     

静电相互作用对荷电超滤过程中带电小分子清除的影响

研究了不同荷电量小分子(分子量为1 kD左右)通过表面带同种电荷但荷电量不同的超滤膜(截留分子量为10 kD)时的行为.实验结果表明,荷电超滤膜对带电小分子的截留作用与超滤膜荷电量、小分子带电量以及溶液离子强度密切相关.低离子强度条件下,荷电超滤膜对高荷电小分子的截留率很高,这主要是静电相互作用的结果.随着离子强度的增加,静电屏蔽作用增强,荷电超滤膜对带电小分子的截留作用也相应减小.结果还表明,表观透过率的实验值与基于滞膜模型的理论计算值有较好的吻合.     

Isotherms,kinetics and thermodynamic studies of adsorption of Ni and Cu by modification of Al2O3 nanoparticles with natural organic matter

In this study, removal of Ni and Cu ions from aqueous media was assessed by the adsorption of Al₂O₃ nanoparticles (ANPs), with surface modification by natural organic matter (NOM). The obtained materials (NOM–ANPs) were characterized by Fourier transform infrared spectroscopy. Then, batch adsorption methods were carried out as a function of contact time, adsorbate concentration, pH and temperature. Kinetic experiments revealed that the pseudo-second-order model exhibited the best correlation with the adsorption data, the estimated maximum adsorption capacity of Ni and Cu could reach 15.38 and 62.50 mg g^?1 respectively at 303 K, displaying higher efficiency for Ni and Cu removal than previously reported adsorbent materials reported in the literature. Thermodynamic studies exposed the feasibility and endothermic nature of the system. The experimental results show the technical feasibility of NOM–ANPs, its easy synthesis, economic and a promising advanced adsorbent in environmental pollution cleanup.