Application of Conducting Polymer Composites With Cellulose Fibers on Water Softening

Hard water is unsuitable for industrial and domestic purposes given its high levels of calcium and magnesium divalents which generate scale, oxidation and are antagonistic of optimal performance of detergents and industrial equipment. Conventional methods for water softening generate by-products that need to be treated, which makes these methods economically and environmentally unsustainable and open the opportunity to develop new technology for this application. The ion exchange behavior during the charge and discharge processes (i.e. oxidation / reduction), of conducting polymers and the combination of these materials with other such as fibers, to develop new hybrid materials that exhibit the inherent properties of both components, has been the object of many studies in the last years. The aim of this study is to evaluate the applicability of vegetable cellulose microfibers as a base to obtain a conducting polymer composite membrane with polypyrrole and to analyze the membrane performance to remove ions dissolved in hard water. The application of conducting polymer composite on water softening is based on the use of pyrrole’s electrochemical properties jointed to the flexibility and relatively high surface areas associated with cellulose, to promote an ion exchange reaction between the composite membrane and the hard water. The cellulose membranes obtained from banana plant waste (raquis), were uniform with individual and well separated fibers. The fibers were successfully encapsulated by a continuous coating of polypyrrole through in situ oxidative chemical polymerization. The amount of polypyrrole deposited on the fiber increased with increasing concentrations of the monomer, which was easily identified through the observation of differences on the intensity of the light to dark colour shift that coated the fibers after the polymerization. The applicability of the conducting polymer composite on water softening was tested using an experimental device, finding reductions on the conductivity for hard water within 23 to 66 μs/cm after 6 hours of the assay.