Yue Miao , Xiaowen Huo , Yingying Zhao , Xiuling Liu , Haitao Wang , Jun Li , Na Chang
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引用次数: 0
Abstract
The utilization of surfactants in the fabrication of thin-film composite (TFC) membranes has proven to be an effective way for the regulation of interfacial polymerization (IP) process in order to obtain ideal polyamide (PA) layers. However, the uncontrollable migration of surfactants and the variety in the aggregated state of surfactants result in difficulty in regulation of the morphology of PA layer. Here, nonionic surfactant Span80 is introduced in organic-phase before IP process, and the impact of the transformation of Span80 from single molecules to micelles, as well as the morphology the PA layers is systematically investigated. The function of Span80 in IP process and its impact on improving the uniformity, compactness, and separation performance of the PA layer are demonstrated by molecular simulations. As has been proved that Span80 single molecules or micelles tend to form a surfactant layer composed by Span80 single molecules at the water-organic interface due to the lower interaction energy during their migration from the organic phase to the interface. The formation of this monolayer significantly reduces the water-organic interfacial tension, which promotes the diffusion of piperazine monomer, and accelerates the IP process. As a result, with the increasing Span80 concentration, the morphology of PA layer transforms from granular structure to denser micro-spherical structure. The more uniform PA layer helps to improve the performance of this nanofiltration membrane, with the Li+/Mg2+ separation ratio increasing from 2.41 to 14.72, representing an approximately 6-fold enhancement in separation efficiency.
期刊介绍:
The Journal of Water Process Engineering aims to publish refereed, high-quality research papers with significant novelty and impact in all areas of the engineering of water and wastewater processing . Papers on advanced and novel treatment processes and technologies are particularly welcome. The Journal considers papers in areas such as nanotechnology and biotechnology applications in water, novel oxidation and separation processes, membrane processes (except those for desalination) , catalytic processes for the removal of water contaminants, sustainable processes, water reuse and recycling, water use and wastewater minimization, integrated/hybrid technology, process modeling of water treatment and novel treatment processes. Submissions on the subject of adsorbents, including standard measurements of adsorption kinetics and equilibrium will only be considered if there is a genuine case for novelty and contribution, for example highly novel, sustainable adsorbents and their use: papers on activated carbon-type materials derived from natural matter, or surfactant-modified clays and related minerals, would not fulfil this criterion. The Journal particularly welcomes contributions involving environmentally, economically and socially sustainable technology for water treatment, including those which are energy-efficient, with minimal or no chemical consumption, and capable of water recycling and reuse that minimizes the direct disposal of wastewater to the aquatic environment. Papers that describe novel ideas for solving issues related to water quality and availability are also welcome, as are those that show the transfer of techniques from other disciplines. The Journal will consider papers dealing with processes for various water matrices including drinking water (except desalination), domestic, urban and industrial wastewaters, in addition to their residues. It is expected that the journal will be of particular relevance to chemical and process engineers working in the field. The Journal welcomes Full Text papers, Short Communications, State-of-the-Art Reviews and Letters to Editors and Case Studies