Arsenate removal from aqueous solutions using micellar-enhanced ultrafiltration

Abstract

In this study, arsenate (As-V) removal using micellar enhanced ultrafiltration (MEUF) modified by cationic surfactants was studied by a dead-end polyacrylonitrile (PAN) membrane apparatus. The UF membrane has been produced by a phase inversion process. The prepared membrane was characterized and analyzed for morphology and membrane properties. The influence of operating parameters such as initial concentrations of As-V, surfactants, pH, membrane thickness, and co-existing anions on the removal of As-V, surfactant rejection, and permeate flux have been studied. The experimental results show that from the two different cationic surfactants used the CPC (cetyl-pyridinium chloride) efficiency (91.7%) was higher than that of HTAB (hexadecyltrimethyl-ammonium bromide) (83.7%). The highest As-V removal was 100%, and was achieved using initial feed concentrations of 100-1000 μg/L , at pH 7 with a membrane thickness of 150 μm in a dead-end filtration system. This efficiency for As-V removal was similar to that obtained using a cross-flow system. Nevertheless, this flux reduction was less than the reduction achieved in the dead-end filtration process. The PAN fabricated membrane in comparison to the RO and NF processes selectively removed the arsenic and the anions, in the water taken from the well, and had no substantial effect on the cations.

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“…Their production and extraction methods are continually being optimized to increase efficiency and reduce costs, contributing to a more sustainable and circular economy. Further research is needed to optimize production, develop new formulations, and evaluate their long-term environmental impact [66] that have area of application not only for waste water but sea water also [67].…”

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“…distribution in the aqueous and the micellar phases. Bahmani et al [80,81] reported that micelles composed of CPC resulted in higher arsenic removal (91.7%) compared to CTAB micelles (83.7%), and an increasing removal of both As (V) and NO 3as the CPC concentration was increased, however with an associated decrease in permeate flux.…”

Reusable Nanocomposite Membranes for Highly Efficient Arsenite and Arsenate Dual Removal from Water

“…Currently, different methods with varying degrees of sophistication have been applied for As removal, including filtration, [ 10 ] precipitation, [ 11 ] ion exchange, [ 12 ] electrocoagulation, [ 13 ] biological processes, [ 14 ] membrane separation, [ 15 ] adsorption, [ 16 ] among others. It is important to note that if the removal of As(V) negatively charged species is challenging by itself, the development of technical approaches to retain the As(III) neutral forms is even more difficult.…”

“…[8] The predominance of each arsenic form is dependent on water properties, such as pH and oxidation/reduction potential, but in the most usual conditions found in surface and underground water, As(V) is found as negative oxyanions (i.e., H 2 ) in oxidative conditions, while As(III) is stabilized as the neutral H 3 AsO 3 form in water environments with low oxygen content. [9] Currently, different methods with varying degrees of sophistication have been applied for As removal, including filtration, [10] precipitation, [11] ion exchange, [12] electrocoagulation, [13] biological processes, [14] membrane separation, [15] adsorption, [16] among others. It is important to note that if the removal of As(V) negatively charged species is challenging by itself, the development of technical approaches to retain the As(III) neutral forms is even more difficult.…”