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Fulfilling the demand of clean potable water to the general public has long been a challenging task in most developing countries due to various reasons. Large-scale membrane water treatment systems have proven to be successful in many advanced countries in the past two decades. This paves the way for developing countries to study the feasibility and adopt the utilization of membrane technology in water treatment. There are still many challenges to overcome, particularly on the much higher capital and operational cost of membrane technology compared to the conventional water treatment system. This review aims to delve into the progress of membrane technology for water treatment systems, particularly in developing countries. It first concentrates on membrane classification and its application in water treatment, including membrane technology progress for large-scale water treatment systems. Then, the fouling issue and ways to mitigate the fouling will be discussed. The feasibility of membrane technologies in developing countries was then evaluated, followed by a discussion on the challenges and opportunities of the membrane technology implementation. Finally, the current trend of membrane research was highlighted to address future perspectives of the membrane technologies for clean water production.

BACKGROUND In this work, a series of graphene oxide–polyethersulfone (GO–PES) composite flat sheet (FS) and hollow fiber (HF) membranes were fabricated by blending 0.5 and 1.0 wt% of GO into the PES matrix and utilized for oil–water separation. GO was first prepared and characterized by using Fourier‐transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X‐ray diffraction (XRD) and thermogravimetric analysis (TGA) before being used as membrane fillers. RESULTS Interestingly, although similar dope composition was used for the fabrication of HF and FS membranes, their morphology and pore size varied significantly owing to the way the membranes were fabricated. Significant enhancement of hydrophilicity was observed for both composite FS and HF membranes, where the water contact angle value decreased from 74.8° to 42.2° and 71.4° to 49.8°, respectively. The flux of the composite membranes increased up to 150% of the bare membranes especially when 1.0 wt% of GO was added. Although higher oil rejection (~99%) was observed for HF membranes that possess smaller pores, the permeation flux was maintained due to the improved flow dynamic. Lower oil rejection (up to 50%) was observed for FS membranes, which might be due to its big pore sizes particularly at the bottom surface. As more oil droplets formed on the membrane surface and prevented water molecules to pass through the membrane, fouling might occur rapidly. CONCLUSIONS The results obtained in this work suggest that surface hydrophilicity, pore size of membranes and oil–water separation performances was greatly affected by membrane shape. Owing to many advantages of HF membranes, this type of membrane has great potential for commercial applications. © 2020 Society of Chemical Industry

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Abstract. Production of industrial wastewater is increasing as the oil and gas industry grows rapidly over the years. The constituents in the industrial wastewater such as organic and inorganic matters, dispersed and lubricant oil and metals which have high toxicity become the major concern to the environment and ecosystem. There are many technologies are being used for oil removal from industrial wastewater. However, there are still needs to find an effective technology to treat oily wastewater before in can be discharge safely to the environment. Membrane technology is an attractive separation technology to treat oily wastewater. The aim of this study is to fabricate polyvinylidene/titanium dioxide (PVDF/TiO2) composite membrane with further treatment using hot pressed method to enhance the adhesion between TiO2 with the membrane surfaces. In this study the structural and physical properties of fabricated membrane were conducted using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) respectively. The photocatalytic degradation of oil was measured using UV-Vis Spectroscopy. The FTIR results confirmed that, hot pressed PVDF/TiO2 membrane TiO2 was successfully deposited onto PVDF membranes surface and XRD results shows that the XRD pattern of PVDF//TiO2 found that the crystalline structure was remained unchanged after hot pressed. Clear water was obtained after synthetic oily wastewater was exposed to visible light for at least 6 hours. In conclusion, PVDF/TiO2 composite membrane can be a potential candidate to degrade oil in oily wastewater and suggested to possess an excellent performance if perform simultaneously with membrane separation process.

Foam flooding is an established approach in Enhanced Oil Recovery (EOR) to recover a significant quantity of the residual oil left in the reservoir after primary and secondary recovery. However, foam flooding faces various problems due to low viscosity effect, which reduces its efficiency in recovering oil. Using surfactant to stabilize CO2foam may reduce mobility and improve areal and vertical sweep efficiency, but the potential weaknesses are such that high surfactant retention in porous media and unstable foam properties under high temperature reservoir conditions. Nanoparticles have higher adhesion energy to the fluid interface, which potentially stabilize longer lasting foams. Thus, this paper is aimed to investigate the CO2foam stability and mobility characteristics at different concentration of nanosilica, brine and surfactant. Foam generator has been used to generate CO2foam and analyze its stability under varying nanosilica concentration from 100 - 5000 ppm, while brine salinity and surfactant concentration ranging from 0 to 2.0 wt% NaCl and 0 – 10000 ppm, respectively. Foam stability was investigated through observation of the foam bubble size and the reduction of foam height inside the observation tube. The mobility was reduced as the concentration of nanosilica increased with the presence of surfactant. After 150 minutes of observation, the generated foam height reduced by 10%. Liquid with the presence of both silica nanoparticles and surfactant generated more stable foam with lower mobility. It can be concluded that the increase in concentration of nanosilica and addition of surfactant provided significant effects on the foam stability and mobility, which could enhance oil recovery.