W.N.W. Salleh

An overview on cellulose-based material in tailoring bio-hybrid nanostructured photocatalysts for water treatment and renewable energy applications

A combination between the nanostructured photocatalyst and cellulose-based materials promotes a new functionality of cellulose towards the development of new bio-hybrid materials for various applications especially in water treatment and renewable energy. The excellent compatibility and association between nanostructured photocatalyst and cellulose-based materials was induced by bio-combability and high hydrophilicity of the cellulose components. The electron rich hydroxyl group of celluloses helps to promote superior interaction with photocatalyst. The formation of bio-hybrid nanostructured are attaining huge interest nowadays due to the synergistic properties of individual cellulose-based material and photocatalyst nanoparticles. Therefore, in this review we introduce some cellulose-based material and discusses its compatibility with nanostructured photocatalyst in terms of physical and chemical properties. In addition, we gather information and evidence on the fabrication techniques of cellulose-based hybrid nanostructured photocatalyst and its recent application in the field of water treatment and renewable energy.

Physicochemical characterization of cellulose nanocrystal and nanoporous self-assembled CNC membrane derived from Ceiba pentandra

This research involves the rare utilisation of the kapok fibre (Ceiba pentandra) as a raw material for the fabrication of cellulose nanocrystal (CNC) and self-assembled CNC membranes. The isolation of CNC from Ceiba pentandra began with the extraction of cellulose via the chemical alkali extraction by using 5wt% NaOH, followed by the typical acidified bleaching method and, finally, the CNC production through acid hydrolysis with 60wt% H2SO4 at the optimum time of 60min. The prepared CNC was then employed for the preparation of self-assembled membrane through the water suspension casting evaporation technique. The obtained CNC membrane was characterised in terms of its composition, crystallinity, thermal stability, as well as, structural and morphological features with the use of several techniques including FTIR, XRD, AFM, TEM, FESEM, and TGA. The FESEM and AFM analyses had illustrated the achievement of a self-assembled CNC membrane with a smooth surface and a well-distributed nano-porous structure, with the porosity of 52.82±7.79%. In addition, the findings proved that the self-assembled CNC membrane displayed good adsorption capability indicated by the recorded efficiency of 79% and 85% for 10mg/L and 5mg/L of methylene blue in an aqueous solution, respectively.

A review on the fabrication of electrospun polymer electrolyte membrane for direct methanol fuel cell

Proton exchange membrane (PEM) is an electrolyte which behaves as important indicator for fuel cells performance. Research and development (R&;D) on fabrication of desirable PEM have burgeoned year by year, especially for direct methanol fuel cell (DMFC). However, most of the R&;Ds only focus on the parent polymer electrolyte rather than polymer inorganic composites. This might be due to the difficulties faced in producing good dispersion of inorganic filler within the polymer matrix, which would consequently reduce the DMFCs performance. Electrospinning is a promising technique to cater for this arising problem owing to its more widespread dispersion of inorganic filler within the polymer matrix, which can reduce the size of the filler up to nanoscale. There has been a huge development on fabricating electrolyte nanocomposite membrane, regardless of the effect of electrospun nanocomposite membrane on the fuel cells performance. In this present paper, issues regarding the R&;D on electrospun sulfonated poly (ether ether ketone) (SPEEK)/inorganic nanocomposite fiber are addressed.

Graft copolymerization of acrylonitrile onto recycled newspapers cellulose pulp

The extraction of recycled newspapers (RNP) cellulose pulp began by a series of chemical alkali extraction, 5 wt% NaOH at 125°C for 2 h. Subsequently, the bleaching of alkalized pulp was carried out by using 2 wt% NaClO2 solutions in the presence of 60 wt% of nitric acid, for 4 h at 100°C. The graft copolymerization of acrylonitrile onto the bleached cellulose pulp was initiated by using ceric ammonium nitrate. The grafting conditions were optimized by varying the ceric ammonium nitrate (CAN) initiator concentration, acrylonitrile (ACN) concentration and reaction time. The successfully of the grafting process were determined by calculating the grafting yield (%GY) and grafting efficiency (%GE). The morphological and chemical structure of resulting grafted and ungrafted recycled newspaper cellulose pulp were characterized by using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy.The extraction of recycled newspapers (RNP) cellulose pulp began by a series of chemical alkali extraction, 5 wt% NaOH at 125°C for 2 h. Subsequently, the bleaching of alkalized pulp was carried out by using 2 wt% NaClO2 solutions in the presence of 60 wt% of nitric acid, for 4 h at 100°C. The graft copolymerization of acrylonitrile onto the bleached cellulose pulp was initiated by using ceric ammonium nitrate. The grafting conditions were optimized by varying the ceric ammonium nitrate (CAN) initiator concentration, acrylonitrile (ACN) concentration and reaction time. The successfully of the grafting process were determined by calculating the grafting yield (%GY) and grafting efficiency (%GE). The morphological and chemical structure of resulting grafted and ungrafted recycled newspaper cellulose pulp were characterized by using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy.

P84 Co-Polyimide Based-Tubular Carbon Membrane: Effect of Heating Rates on Helium Separations

Helium is one of the most valuable gases with unique features and properties as well as widely used in various applications. Generally, most of the helium sources was extracted from natural gas and it is very crucial to develop efficient technology for helium recovery from natural gas sources, in order to overcome the deficit of the helium supply. Up to now, there are various available traditional separation methods for helium recovery, however these methods possessed several disadvantages such as expensive in cost and energy intensive. Recently, gas separation by using membranes have been utilized and showed potential in recovering and purifying helium from natural gas. This method directly separating the helium from the methane through natural gas liquefaction process where in this process the helium is recovered from the nitrogen rejection unit (NRU) exit gas. Due to the potential benefits that can be obtained from this membrane-based separation method, this current study is aiming to provide more comprehensive scientific reports on the effects of preparation parameters on the performance of tubular carbon membranes (TCMs) for helium separation. In this study, the carbonization heating rate was varied from 1 to 7°C/min by controlling the final temperature at 800°C under Argon environment for all polymeric tubular membranes. The permeation performance of the resultant TCMs have been determined by using a single permeation apparatus. It is necessary to fine-tuning the carbonization conditions in order to obtain the desired permeation properties. From the results, it can be concluded that the most optimum heating rate was found to be at 3°C/min with 463.86±3.12 selectivity of He/N2 separation.

Hybrid membrane filtration-advanced oxidation processes for removal of pharmaceutical residue

Reports of pharmaceuticals exist in surface water and drinking water around the world, indicate they are ineffectively remove from water and wastewater using conventional treatment technologies. The potential of adverse effect of these pharmaceuticals on public health and aquatic life, also their continuos accumulation have raised the development of water treatment technologies. Hybrid treatment processes like membrane filtration and advance oxidation processes (AOPs) are likely to give rise to efficient simultaneous degradation and separation mechanisms. Conventional membrane filtration techniques can remove the majority of contaminants, but the smallest, undegraded, and stabilized pharmaceutical wastes persist in the treated water. After some 20 years, researchers have recognized the important role of AOPs in the treatment of pharmaceutical wastewater because these technologies are capable of oxidizing recalcitrant, toxic, and non-biodigradable compounds into numerous by-products and finally, inert end-products via the intermediacy of hydroxyl and other radicals. Evidently, membranes are subjected to the fouling phenomenon by the contaminants in wastewater, hence resulting in a reduction of clean water flux and increase in energy demand. In such situations, these membrane hybrid AOPs exert a complementary effect in the elimination of membrane fouling, thus enhancing the performance of the membrane. Therefore, in this review, we describe the basic aspects of the removal and transformation of certain pharmaceuticals via membranes and AOPs. In addition, information and evidences on membrane hybrid AOPs in the field of pharmaceutical wastewater treatment is also presented.

Preparation and characterisation of polyethersulfone/ hydrous ferric oxide mixed matrix membranes with improved hydrophilicity for treatment of oily waste water

The rapid growth in oil and gas industry has led to the large production of oily wastewater. The massive amount of oily wastewater derived from the industry has raised concerns in community especially its adverse impact to the environment. Membrane technology has been in the spotlight in recent advancement to treat the oily wastewater. The major obstacle regarding the membrane technology is fouling due to surfactant adsorption and/or oil droplets plugging the pore, which would lead to a severe decline of the flux and rejection rate. HFO nanoparticles are incorporated into the PES membrane matrix with the aim to improve the hydrophilicity, water permeability as well as the antifouling properties of the membrane. HFO is abundant and easily obtained making it the perfect candidate in developing economical and energy saving membrane operation. Hydrous ferric dioxide (HFO) nanoparticles were synthesised via chemical precipitation method and incorporated in polyethersulfone (PES) to fabricate nanocomposite mixed matrix membranes (MMMs) for ultrafiltration (UF). The resulting membranes were characterised by SEM, FTIR, contact angle goniometer, before further subjected to water permeation test. It was found that contact angle of membrane decreased remarkably with an increase in HMO nanoparticle loading (state the value/ percentage decrement). The pore size at the skin layer however decreased as observed by SEM. As for the UF experiments, pure water permeation rate increased remarkably with increasing nanoparticle loading.