Pectin-Based Polymer Hydrogel as a Carrier for Release of Agricultural Nutrients and Removal of Heavy Metals from Wastewater

A pectin-based hydrogel was used as a remover of Cu2+ and Pb2+ ions from water and wastewater and in the release of phosphate, potassium, and urea. The swelling studies in either aqueous or saline solutions were analyzed at different pressures, and the prediction of profile of water and solute transports was further analyzed on basis of transport process by diffusion in swellable polymer networks. The hydrogel composed of 0.10 g mL(-1) final polymer concentration showed an excellent absorption capacity for removal of Cu2+ and Pb2+ from the solution: 120 mg Cu2+ and 130 mg Pb2+ per g hydrogel, both at pH 5.5. The hydrogel help to conserve water in a pressure range in which a variety of horticultural plants can absorb it. The release process of urea, phosphate, and potassium from the hydrogels is controlled by non-Fickian mechanism with a tendency to macromolecular relaxation. This type of hydrogel is an interesting system for applications in which the efficient use of water is required and release of fertilizers for agriculture. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 3146-3154, 2010