Conductive hollow-fiber membrane using electroless plating surface nickel coating for submerged electrochemical membrane filtration

초록

Surface coating of a polyethylene (PE) membrane was performed using nickel (Ni) via an electroless plating technique combined with an air-blowing method to activate the membrane pore structures. The optimum plating time for formulating the Ni-coating layer was 6 min, considering both membrane permeability and surface conductivity. The membrane fouling caused by sodium alginate was investigated using a submerged electrochemical membrane reactor (SEMR) operated under an electric field. A reduction in membrane fouling was observed, which resulted from the ability of the Ni-coating layer formed on the PE membrane to enhance charge repulsion. The fouling mitigation varies depending on the external voltage applied to the SEMR used to treat the sodium alginate. The effect of charge exclusion on the reduction in membrane fouling was enhanced by increasing the external voltage. However, as the external voltage was higher than -1.5 V, no beneficial impact of the external voltage on fouling mitigation was observed. The membrane anode reactor accelerated membrane fouling with negatively charged sodium alginates toward the Ni-coating layer of the membrane, which is positively charged at a neutral solution pH. Our bench-scale SEMR test confirmed that the intermittent voltage was better than the continuous voltage mode in terms of energy saving. Moreover, there was no difference in the transient behavior of transmembrane pressure (TMP) between the intermittent (1 min on/off and 3 min on/off) and continuous voltages. Multiple chemical cleaning events did not damage the Ni-coating layer, suggesting that the electroless plating technique combined with the air-blowing method for surface coating with a conductive metal on the polymeric membrane should be substantial.

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