6TH International Congress on Technology - Engineering - Kuala Lumpur3 - Malaysia (2018-07-19)

Functional Polymers With Ability To Remove Inorganic Contaminants

Metal ions and oxyanions pollution in water concern to worldwide due the toxic effect on humans. Currently, there are available several technologies to remove metal from aqueous sources, such differential precipitation, solvent extraction, distillation, ion exchange, membranes, and adsorption, etc. Adsorption and ion exchange are the most developed due the easy operation, sledge-free, etc. Being the polymer-based the widely studied and recently the polymer nanocomposites. Membrane filtration easily allows this separation by means of the method known as the liquid-phase polymer-based retention (LPR) technique. Applications of water-soluble polymers, WSPs, to the homogeneous enrichment or selective separation of various metal ions from dilute solutions are been reported. Ultrafiltration is found as the most suitable technique for LPR studies1-2. Polymer-clay nanocomposites researches have presented a great attention from scientific community because nanocomposites materials present enhanced properties (mechanical, thermal, and barrier properties) compared with starting material (unloaded polymers)3. Diverse clays materials have been used as filler in nanocomposites; montmorillonite, kaolinite, vermiculite, among others. In addition, if the polymer contains functional groups able to retain oxyanions, the material can be considered an anion exchange polymer-clay nanocomposite. Under the experimental conditions and through the washing or enrichment methods Cr(VI) removal experiments were carried out at different pH (3, 6, and 9) using water-soluble cationic polymers (WSCPs) containing quaternary ammonium salts with chloride or methylsulfate counterions. The results showed highest retention capacity of oxyanions depending on the pH. Maximum retention capacity for inorganic pollutants was determined by the enrichment method. The removal of V(V) and Mo(VI) by water-soluble polymers in conjunction with ultrafiltration membranes was above 90 % and there was not observed an important effect of the polymer size fraction and the common interferents on the removal. The recovery of the water-soluble polymer was achieved by changing the acidity of the media. For the batch equilibrium procedure under these conditions, the composites exhibited a high sorption reaching almost a 100% of oxyanion removal. Also, the sorption of materials presented a fast kinetics reaching the maximum sorption after less than 30 min of contact. Selectivity experiments were carried out using an arsenic solution in the presence of sulfate anions and the nanocomposites did not exhibit significant decrease in sorption capacity. According to the results, LPR technique and nanocomposites resulted to be very efficient to remove oxy anion contaminants from aqueous solution. It depended strongly from the pH. Keywords: Functional polymers, inorganic pollutants, membranes, removal. REFERENCES 1. B.L. Rivas, E.D. Pereira, M. Palencia, J. S?nchez,“Water-Soluble Functional Polymers in Conjunction with Membranes to Remove Pollutant Ions from Aqueous Solutions” Progr. Polym. Sci., 36, 294-322 (2011). 2. B.L. Rivas, E.D. Pereira, I. Moreno-Villoslada, “Water-Soluble polymer-metal ion interactions” Progr. Polym. Sci., 28, 173-208 (2003). 3. A.A. Zagorodni, Ion Exchange Materials Properties and Applications, 1st ed., Elsevier BV, Amsterdam, 2007. ACKNOWLEDGMENTS Authors thank to FONDECYT (Grant No 1150510) the financial support.
Bernabé L. Rivas, Julio S?nchez, Bruno Urbano