Iron oxide coating of geosynthetic fibers for water treatment applications

摘要

Polypropylene fibers present favorable physical, hydraulic and specific surface areaproperties for use as a raw material or substrate in developing a novel iron-oxide-coated mediumfor the adsorption of heavy metals from drinking water. However, polypropylene fibers have notbeen explored for their ability to retain iron oxide coating under realistic flow rates for watertreatment. This study evaluated the ability of polypropylene to retain its coating under flow ratesused in water treatment, through column studies. A full factorial experimental design was used toevaluate the effects of flow rate, packing scheme (in-plane or cross-plane) and location within thecolumn on iron retention. The polypropylene mat achieved an iron density of 86 mg Fe/g mediumof material and retained 73% of this coating after being subjected to hydraulic flows in the crossplanedirection several times those used in water treatment. This is substantially higher than theamount of iron retained on sand as reported by previous researchers. Further investigation shouldevaluate pre-treatment methods which may facilitate strong chemical bonds between the iron andfiber to create a more consistent coating.