Polypropylene membranes modified with interpenetrating polymer networks for the removal of chromium ions

Abstract

Polypropylene (PP) membranes incorporating poly [(ar-vinylbenzyl) trimethylammonium chloride] P(ClVBTA), and poly[sodium (styrene sulfonate)] P(SSNa) were modified via an "in situ" radical polymerization synthesis. Two methods were used for impregnation of the reactive solution: pressure injection and plasma superficial activation with argon gas. The following conditions were varied: the monomer concentrations, number of injections, and cross-linked concentration. The modified polypropylene membranes were then characterized using scanning electron microscopy/energy dispersive X-ray spectroscopy, Fourier transform-infrared spectroscopy, electrokinetic potential, and Donnan dialysis for the chromium ions transport. The modified membranes exhibited a hydrophilic character with a water uptake capacity between 15% and 20% and a percent modification between 2.5% and 4.0%. This was compared with the results of an unmodified polypropylene membrane as the blank and the mentioned polypropylene membrane has not the capacity to uptake water because this kind of material is highly hydrophobic. Hexavalent chromium ions were efficiently transported by the modified membranes containing P(ClVBTA) via a plasma method and it achieved 59.2% extraction at pH 9.0 using a 1-mol L 21 NaCl extraction agent. Therefore, unmodified polypropylene membrane shows an extraction percentage close to 10% from the hexavalent chromium ions at pH 9.0. In the same way, the trivalent chromium transport using membranes modified with P(SSNa) achieved 49.0% extraction at pH 2.0 using 1 3 10 21 mol L 21 HNO 3 and 1 mol L 21 NaCl as the extraction agents. Moreover, the unmodified polypropylene membrane reached a value close to 10% from the trivalent chromium ions using 1 3 10 21 mol L 21 HNO 3 and 1 mol L 21 NaCl.

Donnan Dialysis Assisted by Interpenetrating Polymer Networks for Chromium Ion Transport in Aqueous Media

“…It is also reported that poly[(ar-vinylbenzyl) trimethylammonium chloride], P(ClVBTA), is effective for removing chromium ions. 25,26 Poly[sodium (styrene sulphonate)], P(SSNa), is an efficient cation exchange polymer. P(SSNa) works to remove metal cations using a polymer-enhanced ultrafiltration technique.…”

“…APS (1 mol %) was used as the radical initiator. The "in situ" free-radical polymerization was performed inside the membrane pores at 70°C for 24 h. 26 The samples were dried in an oven at 50°C and stored in a silica dryer for 24 h. Table 1 shows the experimental design of IPN formation. For MC6 and MA7 membranes, both sides of the polypropylene membrane contacted the plasma argon for 1 min using plasma activation.…”

Preparation and performance of acrylic acid grafted PES ultrafiltration membrane via plasma surface activation

“…acrylic acid (AA)) on the surface of polymer membranes can also be effective in improving their antifouling properties. 33–36…”

“…acrylic acid (AA)) on the surface of polymer membranes can also be effective in improving their antifouling properties. [33][34][35][36] In this study, PES ultrafiltration membranes were modified via remote NH 3 plasma treatment, remote Ar-NH 3 plasma treatment, 37 and remote Ar-NH 3 plasma-initiated grafting of AA to obtain a modified PES ultrafiltration membrane with excellent separation and antifouling properties. Hydrophilicity before and after modification was characterised using water contact angle (WCA) measurements.…”

Generation of thiolated porous surfaces by interpenetrating polymeric networks: study of their surface properties.

“…Actualmente, se han reportado diversas técnicas de modificación de membranas poliméricas, las cuales se pueden dividir principalmente en dos estrategias, la primera consiste en la modificación del polímero precursor previa a la síntesis de la membrana; mientras que la segunda estrategia se basa en la modificación de la matriz polimérica post-síntesis de la membrana [2,11]. De este modo, una técnica de modificación post-síntesis es la generación redes poliméricas interpenetrantes (RPIs), la cual surge como una estrategia simple, eficiente y de fácil implementación para la generación de estructuras poliméricas entrecruzadas o interpenetradas total o parcialmente, caracterizadas por no poseer uniones de tipo covalente entre sí [3,12]. De esta forma es posible el desarrollo de membranas que combinen tanto las propiedades del polímero de soporte como del agente modificante, obteniéndose membranas con propiedades superiores, tales como resistencia térmica, mecánica, entre otras [2][3].…”