Abstract
A novel polyacrylonitrile (PAN)-based ultrafiltration (UF) hollow-fiber membrane was newly synthesized for nanofiltration (NF) applications. This semi-fully NF hollow-fiber membrane was characterized using a variety of analysis techniques. The membrane exhibited higher negative charge and hydrophilicity and lower surface roughness compared to the pristine UF hollow-fiber membrane. Experiments to study the performance and fouling were simulated under laboratory conditions in a cross-flow system and in–out mode using organic compounds, namely, humic acid and sodium alginate. The removal efficiencies of humic acid and sodium alginate were 65% and 73%, respectively, in the pristine hollow-fiber membrane and 93% and 95%, respectively, in the proposed membrane. The flux decline by natural organic matter was less in the case of the proposed membrane compared to that in the pristine membrane. To mitigate organic fouling on the proposed membrane, sodium hypochlorite (NaClO) was used as a chemical enhanced backwashing agent. At a NaClO concentration of 1 mg/L with a backwashing time of 30 s, an optimal flux recovery of 92.1% of the initial permeability of the PAN-NF hollow-fiber membrane was achieved with less membrane degradation. The results of this study will provide practical insight and act as a technical guide for NF-based plant engineers/operators.
Highlights
Published: 23 July 2021Filtration using nanofiltration (NF) membranes is a pressure-driven process employed to remove multivalent cations and low-molecular-weight species selectively with low energy consumption [1,2]
Tubular membrane modules are less susceptible to fouling by particulate matter and require facile cleaning approaches; they offer packing densities only up to 800 m2 /m3, Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
Performance of the PAN-NF HF Membrane removing these contaminants in the PAN-NF HF membranes may be si Figure 2 shows the removal levels of natural organic matter (NOM) (HA and sodiumalginate alginate (SA)) by both the pristine and hydrophobic
Summary
Filtration using nanofiltration (NF) membranes is a pressure-driven process employed to remove multivalent cations and low-molecular-weight species selectively with low energy consumption [1,2]. Due to their higher water permeability and low osmotic pressure, NF membranes are extensively used instead of reverse osmosis (RO) for water softening, treatment of brackish water, surface water, drinking water, and separation processes in the chemical and pharmaceuticals fields [3,4]. Spiral wound membrane modules consume high energy These membranes do not allow back flushing, they are highly susceptible to fouling caused by suspended solids [8]. Tubular membrane modules are less susceptible to fouling by particulate matter and require facile cleaning approaches; they offer packing densities only up to 800 m2 /m3 , Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
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