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Membrane fouling is the major challenges that hinders the widespread application of membrane bioreactor (MBR). Recently, application of electricity in electrically-enhanced MBR (EMBR) to suppress membrane fouling has gained much attention among research communities. This paper presents an overview of developments on EMBR for fouling suppression in wastewater treatment. The flow of electricity has stimulated several electrokinetic processes including electrophoresis/electrochemical process, and electrocoagulation which are the major fouling suppression mechanisms employed in EMBR. In electrophoresis, the membrane fouling is suppressed by the increased electrorepulsive force between negatively-charged foulants and cathode membrane under the influence of an electric field. Besides, electric field also induces simultaneous electrochemical oxidation and reduction which generate chemicals to degrade pollutant in wastewater. On top of that, use of active anode is reminiscent of electrocoagulation which produces cation coagulants in EMBR that capable to neutralize charge of the foulants and promotes flocs formation. This increases flocs size and sedimentation rate thereafter reduces adhesion of foulants on the membrane surface. Lastly, bioelectricity generation of microbial fuel cell (MFC) integrated with MBR to attain self-sustained EMBR has been studied. Self-sustained EMBR combines the advantages of MFC and MBR in treating wastewater and energy recovery simultaneously. Overall, it is evidenced that MBR and electrokinetic processes have a synergetic enhancement effect in EMBR system.

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In this study, hematite graphene oxide (αFe2O3-GO) powder nanocomposites and thin-film hematite graphene oxide (αFe2O3-GO) were synthesized for application in the removal of Rhodamine B (RhB) from textile wastewater. αFe2O3-GO nanomaterials were placed onto the FTO substrate to form a thin layer of nanocomposites. Different analysis including XRD, FTIR, Raman spectra, XPS, and FESEM were done to analyze the morphology, structure, and properties of the synthesized composites as well as the chemical interactions of αFe2O3 with GO. The photocatalytic performance of two synthesized composites was compared with different concentrations of αFe2O3-GO. The results showed that powder nanocomposites are more effective than thin-film composites for the removal of RhB dye. αFe2O3-GO-5% powder nanocomposites removed over 64% of dye while thin-film nanocomposites had less removal efficiencies with just under 47% removal rate. The reusability test was done for both materials in which αFe2O3-GO-5% powder nanocomposites removed a higher rate of dye (up to 63%) in more cycles (6 cycles).

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Oil palm fronds (OPF) is one of the largest biomass sources in Malaysia that has been underutilized. In this work, OPF has been used as a precursor to synthesize carbon dots (CDs) via microwave irradiation method. The impacts of irradiation power and duration and the reacting solution have been investigated. It was discovered that CDs with the highest photoluminescence intensity was obtained at microwave irradiation power of 385 W for 30 s. Irradiation at lower or higher power resulted in incomplete or over carbonization that reduced the fluorescence property. In addition, CDs synthesized with diethylene glycol (DEG) as reacting solution possessed higher photoluminescence intensity as compared to ultrapure water solution. This could be attributed to more complete CDs formation that happened at higher temperature, which could only be achieved by DEG solution (higher boiling point). The CDs were then tested as a sensor for lead (II) ions. The UV-vis absorbance was found to be reduced with the presence of lead (II) ions. This indicated that the lead (II) ions might interact with CDs and disrupted with the absorbance of UV light. Overall, OPF could be a potential precursor for the synthesis of low-cost and easily available CDs for environmental applications.