Water purification via interfacially polymerized thin film composite membranes

Thin film composite polyesteramide nanofiltration membranes were fabricated with interfacial polymerization from carboxylated chitosan and trimesoyl chloride on a microporous polysulfone support membrane. Salt rejection was improved by building a multiple-layer structure that was formed by sequentially repeating the cycles of the interfacial reactions. The chemical structure, surface morphology and charge were characterized for the polyesteramide top layer. The effects of the concentrations of the reactant solutions and the number of cycles of reactant depositions and reactions on the separation performance were investigated. The single-layer polyesteramide membrane produced from 3.5 wt% carboxylated chitosan and 0.7 wt% TMC has a negatively charged surface and shows favorable separation performance: pure water permeation flux of 7.3 L/(m2 h) at 0.6 MPa gauge feed pressure, and salt rejection of 95.0% for Na2SO4, 65.7% for MgSO4, 33.2% for MgCl2 and 66.3% for NaCl. The multiple-layer polyesteramide membranes show a more negatively charged surface and higher salt rejection than the single-layer polyesteramide membranes. The single-layer polyesteramide membrane PS-[(C-CS)1.0/TMC] with a relatively loose structure shows good retention for the reactive black 5 anionic dye. This study opens an interesting research area to explore a new type of thin film composite nanofiltration membrane.

Preparation of Thin Film Composite Nanofiltration Membrane by Interfacial Polymerization with 3,5-Diaminobenzoylpiperazine and Trimesoyl Chloride

One process involved in biorefinery for generation of value‐added products is fermentation. After fermentation, the downstream bioproduct purification process is conventionally performed by organic solvent extraction, which is environmentally‐hazardous and costly. Membrane‐based separation is a cost‐efficient and environmentally‐benign method for bioproduct separation and purification. In this study, a thin film composite (TFC) nanofiltration (NF) membrane was prepared and the pore size and charge of the polyamide layer were controlled by introducing iminodiacetic acid (IDA), a charged monoamine monomer, with piperazine (PIP) during interfacial polymerization (IP). The newly‐developed NF membrane was found to have a molecular weight cut‐off (MWCO) of 500 to 1350 Da, allowing the permeation of the fermentation product, while rejecting other higher molecular weight compounds. IDA addition in the aqueous amine solution during IP effectively engineered the MWCO values and pore sizes of TFC NF membranes for specific applications, such as separation of fermentation bioproducts. This study successfully showed that IDA reduced the diffusivity of PIP during IP, which negatively affected the polyamide formation and membrane performance. The optimal PIP:IDA concentration ratio was determined by MWCO and effective pore diameter for effective bioproduct separation and purification, which could not be performed by the current commercially‐available NF membranes.

In situ manipulation of properties and performance of polyethyleneimine nanofiltration membranes by polyethylenimine-dextran conjugate

Few-layers MoS2 nanosheets modified thin film composite nanofiltration membranes with improved separation performance

Interfacial polymerization of thin film selective membrane layers: Effect of polyketone substrates

CO2/CH4 separation using inside coated thin film composite hollow fiber membranes prepared by interfacial polymerization

Development of a novel high flux and fouling-resistant thin film composite nanofiltration membrane by embedding reduced graphene oxide/TiO2

With the blooming of oil and gas industries, oily saline wastewater treatment becomes a viable option to resolve the oily water disposal issue and to provide a source of water for beneficial use. Reverse osmosis (RO) has been touted as a promising technology for oily saline wastewater treatment. However, one great challenge of RO membrane is fouling phenomena, which is caused by the presence of hydrocarbon contents in the oily saline wastewater. This study focuses on the fabrication of antifouling RO membrane for accomplishing simultaneous separation of salt and oil. Thin film nanocomposite (TFN) RO membrane was formed by the layer by layer (LbL) assembly of positively charged TNS (pTNS) and negatively charged TNS (nTNS) on the surface of thin film composite (TFC) membrane. The unique features, rendered by hydrophilic TNS bilayer assembled on TFC membrane in the formation of a hydration layer to enhance the fouling resistance by high concentration oily saline water while maintaining the salt rejection, were discussed in this study. The characterization findings revealed that the surface properties of membrane were improved in terms of surface hydrophilicity, surface roughness, and polyamide(PA) cross-linking. The TFC RO membrane coated with 2-bilayer of TNS achieved >99% and >98% for oil and salt rejection, respectively. During the long-term study, the 2TNS-PA TFN membrane outperformed the pristine TFC membrane by exhibiting high permeability and much lower fouling propensity for low to high concentration of oily saline water concentration (1000 ppm, 5000 ppm and 10,000 ppm) over a 960 min operation. Meanwhile, the average permeability of uncoated TFC membrane could only be recovered by 95.7%, 89.1% and 82.9% for 1000 ppm, 5000 ppm and 10,000 ppm of the oily saline feedwater, respectively. The 2TNS-PA TFN membrane achieved almost 100% flux recovery for three cycles by hydraulic washing.

Support membrane pore blockage (SMPB): An important phenomenon during the fabrication of thin film composite membrane via interfacial polymerization

Development of a novel thin film composite membrane by interfacial polymerization on polyetherimide/modified SiO2 support for organic solvent nanofiltration

Polyvinyl alcohol as the barrier layer in thin film composite nanofiltration membranes: Preparation, characterization, and performance evaluation

Improved performance of thin-film composite membrane with PVDF/PFSA substrate for forward osmosis process

Interfacially polymerized thin-film composite polyamide membranes: Effects of annealing processes on pervaporative dehydration of aqueous alcohol solutions

Novel poly(ester amide) nanofiltration membranes fabricated utilizing 4-hydroxypiperidine as a co-reactive monomer for monovalent/divalent anionic salt separation