(376as) Zero Valent Iron Nps Impregnated UF Membrane for Nitrobenzene Reduction and Fluoride Rejection

Piyal Mondal, Mihir Kumar Purkait*

Iron nanoparticle (NPs) impregnated PVDF-co-HFP membrane was prepared by a novel method of phase inversion technique where instead of water, 0.5 (M) FeSO₄ solution was used as non-solvent. The phase inversed casted membrane was then dipped into a solution (70 ºC) of clove extract (optimized with respect to total flavonoid and phenolic content). Green synthesis of iron nanoparticles on the membrane surface and within the pores occurs where iron salt solution remains during phase inversion process. The surface and cross-sectional FESEM morphology images confirms the formation and well homogenous distribution of iron NPs over the membrane and within the pores.

Clove extract acts as reducing agent for the iron salt. Freshly prepared zero valent iron NPs impregnated membrane was then used for nitrobenzene reduction (initial concentration 100 ppm) and fluoride removal study. After each run of nitrobenzene reduction study zero valent iron gets oxidized. In order to reuse and retain the reduction capacity of the membrane 0.1N HCl and H₂SO₄ mixture was passed through the membrane and again it was dipped in the prepared clove extract solution.

It was observed that aniline formation was 19.5 ppm during 1^st run at first 10 min of operation and gradually the value decreases to 14.4 ppm and 13.7 ppm at the end of 2^nd and 3^rd run respectively. Moreover the iron oxide formed on the membrane surface and membrane pores contributed well towards the fluoride rejection study due to increased surface area of iron NPs. The maximum fluoride removal was observed 72.4% during 1^st run for 20 ppm stock solution and it gradually decreases with lower initial fluoride concentration (69.4% for 10 ppm solution and 55.2% for 5 ppm solution). Similarly with run order the values gradually decreases . Hence, through this investigation a reusable membrane for nitrobenzene reduction and fluoride rejection was fabricated by a new technique where FeSO₄ solution used as non solvent additive during phase inversion process.