Thompson Sam, Gutierrez Angela M, Bukowski Jennifer, Bhattacharyya Dibakar
Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA.
Sustainability and Analytical Equipment Facility, University of Kentucky, Lexington, KY 40506, USA.
Molecules. 2024 Sep 6;29(17):4229. doi: 10.3390/molecules29174229.
The widespread production and use of multi-fluorinated carbon-based substances for a variety of purposes has contributed to the contamination of the global water supply in recent decades. Conventional wastewater treatment can reduce contaminants to acceptable levels, but the concentrated retentate stream is still a burden to the environment. A selective anion-exchange membrane capable of capture and controlled release could further concentrate necessary contaminants, making their eventual degradation or long-term storage easier. To this end, commercial microfiltration membranes were modified using pore functionalization to incorporate an anion-exchange moiety within the membrane matrix. This functionalization was performed with primary and quaternary amine-containing polymer networks ranging from weak to strong basic residues. Membrane loading ranged from 0.22 to 0.85 mmol/g membrane and 0.97 to 3.4 mmol/g membrane for quaternary and primary functionalization, respectively. Modified membranes exhibited a range of water permeances within approximately 45-131 LMH/bar. The removal of PFASs from aqueous streams was analyzed for both "long-chain" and "short-chain" analytes, perfluorooctanoic acid and perfluorobutyric acid, respectively. Synthesized membranes demonstrated as high as 90% rejection of perfluorooctanoic acid and 50-80% rejection of perfluorobutyric acid after 30% permeate recovery. Regenerated membranes maintained the capture performance for three cycles of continuous operation. The efficiency of capture and reuse can be improved through the consideration of charge density, water flux, and influent contaminant concentration. This process is not limited by the substrate and, thus, is able to be implemented on other platforms. This research advances a versatile membrane platform for environmentally relevant applications that seek to help increase the global availability of safe drinking water.
近几十年来，多种用途的多氟碳基物质的广泛生产和使用导致了全球供水的污染。传统的废水处理可以将污染物降低到可接受的水平，但浓缩的截留液流仍然是环境负担。一种能够捕获和控制释放的选择性阴离子交换膜可以进一步浓缩必要的污染物，使其最终降解或长期储存更容易。为此，通过孔功能化对商业微滤膜进行改性，以在膜基质中引入阴离子交换部分。这种功能化是用含有伯胺和季胺的聚合物网络进行的，其碱性残基从弱到强。季铵化和伯胺功能化的膜负载量分别为0.22至0.85 mmol/g膜和0.97至3.4 mmol/g膜。改性膜的水渗透率范围约为45-131 LMH/bar。分别针对“长链”和“短链”分析物全氟辛酸和全氟丁酸，分析了从水流中去除全氟辛烷磺酸的情况。合成膜在渗透液回收率达到30%后，对全氟辛酸的截留率高达90%，对全氟丁酸的截留率为50-80%。再生膜在三个连续运行周期中保持了捕获性能。通过考虑电荷密度、水通量和进水污染物浓度，可以提高捕获和再利用效率。这个过程不受底物的限制，因此能够在其他平台上实施。这项研究推进了一个多功能膜平台，用于与环境相关的应用，旨在帮助增加全球安全饮用水的供应量。
