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Improvement of Ultrafiltration for Treatment of Phosphorus-Containing Water by a Lanthanum-Modified Aminated Polyacrylonitrile Membrane
journal contribution
posted on 2020-03-26, 00:13 authored by Kok Yuen Koh, Sui Zhang, J. Paul ChenPhosphorus
contamination in fresh water has posed a great risk
to aquatic ecosystems and human health due to extensive eutrophication.
In this paper, we are reporting a lanthanum (La)-modified aminated
polyacrylonitrile (PAN) adsorptive membrane for effective decontamination
of phosphorus from the simulated water. The PAN membrane was first
aminated to introduce the amine group as an active site for La and
then followed by the in situ precipitation of La particles. The kinetics
study showed that the rapid adsorption occurred within the initial
4 h with the equilibrium established at 8 h. The membrane worked well
in the acidic pH region, with optimal pH 4 and 5 without and with
the pH control, respectively. The maximum adsorption capacities were
50 and 44.64 mg/g at pH 5 and 7, respectively. The adsorption of phosphorus
was not affected by the existence of commonly existing anions except
fluorides in water. In the filtration study, it was observed that
the removal of phosphorus remained the optimum, although the operating
pressure was increased from 1 to 3 bar. The modified membrane was
able to treat 0.32 L of a 10 mg/L phosphate solution to meet the maximum
allowable limit of 0.15 mg/L for the trade effluent. The mechanism
study revealed that the removal was primarily associated with the
ion exchange between a phosphorus ion and a hydroxyl group from the
La particles.