Ultrafiltration membrane for effective removal of chromium ions from potable water

M R Muthumareeswaran,Gopal Prasad Agarwal,Mansour Alhoshan

doi:10.1038/srep41423

M R Muthumareeswaran, Gopal Prasad Agarwal + Show 1 more

Open Access

https://doi.org/10.1038/srep41423

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Abstract

The objective of the present work was to investigate the efficacy of indigenously developed polyacrylonitrile (PAN) based ultrafiltration (UF) membrane for chromium ions removal from potable water. The hydrolyzed PAN membranes effectively rejected chromium anions in the feed ranging from 250 ppb to 400 ppm and a rejection of ≥90% was achieved for pH ≥ 7 at low chromate concentration (≤25 ppm) in feed. The rejection mechanism of chromium ions was strongly dependent on Donnan exclusion principle, while size exclusion principle for UF did not play a major role on ions rejection. Feed pH played a vital role in changing porosity of membrane, which influenced the retention behavior of chromate ions. Cross-flow velocity, pressure did not play significant role for ions rejection at low feed concentration. However, at higher feed concentration (≥400 ppm), concentration polarization became important and it reduced the chromate rejection to 32% at low cross flow and high pressure. Donnan steric-partitioning pore and dielectric exclusion model (DSPM-DE) was applied to evaluate the chromate ions transport through PAN UF membrane as a function of flux by using optimized model parameters and the simulated data matched well with experimental results.

Highlights

Microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO) which depends on applied pressure and pore size of membrane
The key objective of this study was to demonstrate a process for chromium rejection from water via indigenously developed surface modified Polyacrylonitrile (PAN) ultrafiltration membrane, as a feasible method of chromium removal from potable water with low operating pressure
The solution pH played a significant role on rejection properties of chromate ions and more than 90% rejection was achieved at pH ≥ 7 at a low chromium concentration (i.e. ≤25 ppm) in feed; which approached to beyond detectable limits for concentration of 50 ppb

Summary

Introduction

Microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO) which depends on applied pressure and pore size of membrane. The separation processes in MEUF were dependent on electrostatic forces, in which chromate ions was bound to the surface of opposite charged micelles. Bohdziewicz[15] examined the effective removal of chromium ions in PEUF processes, in which chromate ions removed >95% in the presence of hexadecylpyridine chloride complex via 17% of PAN based UF membrane. Korus and Loska[16] examined the effective removal of chromium species in PEUF membrane process. In this case, the sodium polyacrylate was bound with chromite and chromate in turn was bound with polyethylenimine, which retained more than 90% of both species. Chromate ions transport through surface modified PAN ultrafiltration membrane was studied by DSPM-DE model to understand the relationship between the parameters of membrane, solutes, and their interaction

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