Karami Pooria, Khorshidi Behnam, Shamaei Laleh, Beaulieu Eric, Soares João B P, Sadrzadeh Mohtada
Department of Mechanical Engineering, 10-367 Donadeo Innovation Center for Engineering, Advanced Water Research Lab (AWRL), University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
Department of Chemical & Materials Engineering, 12-263 Donadeo Innovation Centre for Engineering, Group of Applied Macromolecular Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
ACS Appl Mater Interfaces. 2020 Nov 25;12(47):53274-53285. doi: 10.1021/acsami.0c15194. Epub 2020 Nov 10.
Despite growing demands for high-temperature wastewater treatment, most available polymeric membranes are limited to mild operating temperatures (<50 °C) and become less efficient at high temperatures. Herein we show how to make thermally stable reverse osmosis thin-film nanocomposite (TFN) membranes by embedding nanodiamond (ND) particles. Polyamide composite layers containing different loadings of surface-modified ND particles were synthesized through interfacial polymerization. The reactive functional groups and the hydrophilic surface of the NDs intensified the interactions of the nanoparticles with the polymer matrix and increased the surface wettability of the TFN membranes. Contact angle measurement showed a maximum decrease from 88.4° for the pristine membrane to 58.3° for the TFN membrane fabricated with 400 ppm ND particles. The addition of ND particles and ethyl acetate created larger surface features on the polyamide surface of TFN membranes. The average roughness of the membranes increased from 108.4 nm for the pristine membrane to 177.5 nm for the TFN membrane prepared with highest ND concentration. The ND-modified TFN membranes showed a higher pure water flux (up to 76.5 LMH) than the pristine membrane (17 LMH) at ambient temperature at 220 psi and room temperature. The TFN membrane with the highest loading of ND particles overcame the trade-off relation between the water flux and NaCl rejection with 76.5 LMH and 97.3% when 2000 ppm of NaCl solution was filtered at 220 psi. Furthermore, with increasing ND concentration, the TFN membrane showed a lower flux decline at high temperatures over time. The TFN400 prepared with 400 ppm of -phenylene diamine functionalized ND particles had a 13% flux decline over a 9 h filtration test at 75 °C. This research provides a promising path to the development of high-performance TFN membranes with enhanced thermal stability for the treatment of wastewaters at high temperatures.
尽管对高温废水处理的需求不断增长，但大多数现有的聚合物膜仅限于温和的操作温度（<50°C），在高温下效率会降低。在此，我们展示了如何通过嵌入纳米金刚石（ND）颗粒来制备热稳定的反渗透薄膜纳米复合（TFN）膜。通过界面聚合合成了含有不同负载量表面改性ND颗粒的聚酰胺复合层。NDs的反应性官能团和亲水表面增强了纳米颗粒与聚合物基体的相互作用，并提高了TFN膜的表面润湿性。接触角测量显示，从原始膜的88.4°最大下降到用400 ppm ND颗粒制备的TFN膜的58.3°。添加ND颗粒和乙酸乙酯在TFN膜的聚酰胺表面上产生了更大的表面特征。膜的平均粗糙度从原始膜的108.4 nm增加到用最高ND浓度制备的TFN膜的177.5 nm。在220 psi和室温的环境温度下，ND改性的TFN膜显示出比原始膜（17 LMH）更高的纯水通量（高达76.5 LMH）。当在220 psi下过滤2000 ppm的NaCl溶液时，具有最高负载量ND颗粒的TFN膜克服了水通量和NaCl截留率之间的权衡关系，水通量为76.5 LMH，截留率为97.3%。此外，随着ND浓度的增加，TFN膜在高温下随时间的通量下降更低。用400 ppm对苯二胺官能化的ND颗粒制备的TFN400在75°C下进行9小时过滤测试时通量下降了13%。这项研究为开发具有增强热稳定性的高性能TFN膜以处理高温废水提供了一条有前景的途径。
