Fabrication of polyamide thin-film nanocomposite membranes with enhanced surface charge for nitrate ion removal from water resources

Abstract

Exclusion due to membrane surface charge is considered as one of the main separation mechanisms occurring in charged membranes, which can be varied through various approaches to affect membrane rejection performance. In this study, thin-film composite (TFC) polyamide (PA) membranes were fabricated via interfacial polymerization of m-phenylenediamine (m-PDA) and 2,4-diaminobenzene sulfonic acid with trimesoyl chloride (TMC) on a polysulfone sub-layer. The ability of the prepared membrane to remove nitrate ions from water resources has been investigated. In order to improve membrane permeability, zeolite-PA thin film nanocomposite (TFN) membranes were fabricated by incorporating natural zeolite nanoparticles obtained through ball milling of an Iranian natural zeolite powder in the interfacial polymerization process. The size, morphology and specific surface area of the as-obtained nanozeolite were characterized using particle size analysis, FE-SEM and BET. The functional groups, morphology and surface charge of the membrane were characterized using ATR-FTIR, SEM and zeta potential analyses. Also, field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS) were used to determine the distribution of nanozeolite in TFN membranes. The influence of zeolite addition to surface roughness was accessed by atomic force microscopy. The performance of TFC and TFN membranes was evaluated in terms of pure water flux and nitrate rejection. The results showed that in case of sulfonated diamine, nitrate ions rejection was enhanced from 63% to 85% which could be attributed to surface charge enhancement. TFN permeability was almost doubled by the addition of nanozeolite.

Thin‐Film Nanocomposite Nanofiltration Membranes Incorporated with Graphene Oxide for Phosphorus Removal

“…However, the membrane properties can be improved by modifying the thin layer using hydrophilic nanoparticles . The nanoparticles that have been previously used for TFN membrane synthesis include zeolite , titanium dioxide (TiO 2 ) , , graphene oxide (GO) , , silver , silica , and metal‐organic frameworks (MOFs) , . Previous studies showed that the incorporation of nanoparticles generally help to boost up the water permeation flux, mainly attributed to alteration of membrane surface hydrophilicity , .…”

“…Previous studies showed that the incorporation of nanoparticles generally help to boost up the water permeation flux, mainly attributed to alteration of membrane surface hydrophilicity , . Other positive features of adding nanomaterials into the matrix of composite membranes involve increased solute rejection rates , better antibacterial properties , and stronger resistance against organic/inorganic fouling .…”

Research on English Movie Resource Information Mining Based on Dynamic Data Stream Classification

“…e model uses a basic 3-layer topology, namely, the input layer, the hidden layer, and the output layer. e input layer has 7 nodes, which represent 7 relevant factors that affect the task price [16,40]. Concept drift refers to the phenomenon that the concepts implicit in the data change over time.…”

“…In the film industry, through the analysis of massive amounts of film and television data, the application system can effectively push the works that users may like. Recently, some film production companies have tried to use the results of data analysis to design castings and scripts, and their works have been very successful [11][12][13][14][15][16][17][18]. Movie data contains a wealth of information, but the current mining and analysis work for it often only focuses on specific information, which affects the integrity of the results to a certain extent.…”

Concentration of viruses and electron microscopy

“…Hybrid NF membranes are also of interest due to their performance under suboptimal conditions. Various polymers, such as po lyethersulfone (Maximous et al, 2009), polydimethylsiloxane (Yousefi et al, 2017), polyvinylidene fluoride (Dong et al, 2013), and polysulfone (Ghaee et al, 2017) were tested as top layer materials for hybrid membranes. The use of polymers for obtaining hybrid NF membranes makes it possible to change pore sizes, chemical properties, and charges of membrane surfaces.…”