Preparation Of Thin Film Composite Membranes Research Articles

Novel thin film composite membrane fabricated by mixed matrix nanoclay/chitosan on PVDF microfiltration support: Preparation, characterization and performance in dye removal

Novel thin film composite (TFC) membrane was prepared by organoclay/chitosan nanocomposite coated on the commercial polyvinylidene fluoride (PVDF) microfiltration membrane. The procedure was set to prepare a PVDF/chitosan TFC membrane without applying a cross-linker agent. Various quantities of two different grades of organoclay (Cloisite 15A and 30B) were added into chitosan solution to find the optimum value and to compare the effect of organic modifier of clay nanoparticles on the prepared TFC characteristics. The membranes were examined with aqueous dye solution regarding to the performance qualification. The results showed that formation of coating layer decreased the water flux in all the prepared TFC membranes. Methylene blue dye removal increased with applying organoclay particles in chitosan coating. Cloisite 15A and 30B showed different properties in elimination of various dyes as well as alteration of feed acidity. The morphology of fabricated TFC membranes was compared to each other using scanning electron microscopy (SEM). The coating layer containing Cloisite 30B was denser rather than that of Cloisite 15A. X-ray diffraction pattern of prepared nanocomposites containing organoclay and chitosan indicated greater d-spacing for Cloisite 15A rather than 30B. The investigation of functional groups in clay/chitosan nanocomposite coating was performed by Fourier transform infrared spectroscopy (FTIR). The chemical structure (functional groups) of prepared TFC membranes offered adsorption as dominating dye removal mechanism.

PTFE/polyamide thin-film composite membranes using PTFE films modified with ethylene diamine polymer and interfacial polymerization: Preparation and pervaporation application

Plasma polymerization of ethylene diamine (EDA) on PTFE film surfaces is applied to modify PTFE surfaces to become hydrophilic and to incorporate amino groups onto PTFE surfaces. The surface-modified PTFE films are utilized as substrates for interfacial polymerization of EDA and trimesoyl chloride to prepare PTFE/polyamide thin-film composite (TFC) membranes. The effect of plasma power for plasma polymerization on the morphology and performances of the PTFE/PA TFC membranes are examined and discussed. The presence of amino groups on the PTFE substrates provides chemical linkages between PTFE and PA layers in interfacial polymerization to make the PTFE/PA TFC membranes are stable for pervaporation separations. A high permeation flux of 1910 g/h m 2 and a separation factor of 290 are observed with the PTFE/PA TFC membranes for pervaporation dehydration on a 70 wt% isopropanol aqueous solution at 70 °C. This approach explores a new method to prepare PTFE-based TFC membranes via interfacial polymerizations. The prepared TFC membranes could be potentially utilized in pervaporation and nanofiltration separations.

Novel thin-film composite membranes with improved water flux from sulfonated cardo poly(arylene ether sulfone) bearing pendant amino groups

A new class of polymeric amine, namely, sulfonated cardo poly(arylene ether sulfone) (SPES-NH 2) was synthesized and used for the preparation of thin-film composite membrane. The TFC membranes were prepared on a polysulfone supporting film through interfacial polymerization with trimesoyl chloride (TMC) solutions and amine solutions containing SPES-NH 2 and m-phenylenediamine (MPDA). The resultant membranes were characterized with water permeation performance, chemical structure, hydrophilicity of active layer and membrane morphology including top surface and cross-section. The membrane prepared under the optimum condition showed the salt rejection and water flux reached 97.3% and 51.2 L/m 2 h, respectively. The high salt rejection and water flux was attributed to the rigid polymer backbone and the presence of strong hydrophilic sulfonic groups.

Study of reverse osmosis separation and permeation rate for sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide) membranes of different ion exchange capacities

AbstractThe reverse osmosis performance of thin‐film composite membranes prepared from sulfonated polyphenylene oxide polymer with different ion‐exchange capacities was studied using various electrolyte solutes. The effect of the solvent used for the preparation of the polymer solution for surface coating was also studied. It was found that the preparation of thin‐film composite membranes with high selectivities and high fluxes was possible by adjusting properly the ion‐exchange capacity and the solvent. It was also found that the membrane performance was governed primarily by the ion‐exchange reaction between the solute cation and the proton in SO3H and the Donnan equilibrium. © 1995 John Wiley & Sons, Inc.