Suzylawati Ismail

Water recycling from palm oil mill effluent (POME) using membrane technology

Malaysia is the largest producer and exporter of palm oil. Palm oil processing is carried out in palm oil mills where oil is extracted from a palm oil fruit bunch. Large quantities of water are used during the extraction of crude palm oil from the fresh fruit bunch, and about 50% of the water results in palm oil mill effluent (POME). POME is a thick brownish liquid that contains high amounts of total solids (40,500 mg/L), oil and grease (4000 mg/L), COD (50,000 mg/L) and BOD (25,000 mg/L). The disposal of this highly polluting effluent is becoming a major problem if it is not being treated properly besides a stringent standard limit imposed by The Malaysian Department of Environment for effluent discharged. A POME treatment system based on membrane technology shows high potential for eliminating the environmental problem, and in addition, this alternative treatment system offers water recycling. The treated effluent has a high quality and crystal clear water that can be used as the boiler feed water or as the source of drinking water production. In our current research, a pilot plant was designed and constructed for POME treatment; two stages of treatment have been conducted whereby coagulation, sedimentation and adsorption play their roles at the first stage as a membrane pretreatment process, and ultrafiltration and reverse osmosis membranes are combined for the membrane separation treatment. Results from the total treatment system show a reduction in turbidity, COD and BOD up to 100%, 98.8% and 99.4%, respectively, with a final pH of 7. Thus, the results show that this treatment system has a high potential for producing boiler feed water that can be recycled back to the plant.

Membrane Antifouling Methods and Alternatives: Ultrasound Approach

Membranes are widely used in separation processes. Various industries use membranes as part of their production processes. However, one of the main problems in membrane separation processes is fouling. The fouling mechanism is briefly reviewed in this paper. Fouling can be controlled before it happens. Alternatively, membranes can be cleaned after fouling occurs. Several control methods such as feed pre-treatment, material selection and membrane surface modification can be applied. Cleaning methods can be categorized into several techniques: chemical, mechanical, hydrodynamic, electrical and ultrasonic cleaning methods. This paper focuses on the ultrasonic cleaning method, which is an additional force that aids filtration. The mechanism of the ultrasonic wave that reduces fouling by cavitation and acoustic streaming is reviewed. The advantages and disadvantages of ultrasound irradiation as a cleaning method are also discussed in this paper. The apparatus design and factors that influence the effectiveness of ultrasound treatments, including frequency, power intensity, feed properties, membrane properties, cross-flow velocity, temperature and pressure, are analysed. Recently, ultrasound irradiation combined with other techniques has gained increasing attention. It has been discovered that a combination of other cleaning methods with ultrasound irradiation led to the removal of the fouling layers from the membrane surface.

Carbon Nanotubes (CNTs) Nanocomposite Hydrogels Developed for Various Applications: A Critical Review

Interest in the development of polymeric hydrogels impregnated with carbon-nanotubes (CNTs) is growing rapidly in recent times owing to their usefulness in many fields of human endeavor. This review paper serves as an archive of literature reports of several researchers who have worked on polymeric hydrogels embedded with CNTs for diverse applications. The review covers up to date research advancement on the synthesis and characterization properties of CNTs nanocomposite hydrogels. Besides, this review discusses extensively the various fields in which polymeric hydrogels infused with CNTs have been applied. This unprecedented compilation of CNTs nanocomposite hydrogels information into a single revision allows a straightforward comparison of studies performed for diverse applications.

Preparation and characterisation of PES-ZnO mixed matrix membranes for humic acid removal

AbstractZinc oxide nanoparticles (ZnO-NPs) were incorporated into polyethersulfone (PES) matrix to prepare mixed matrix membranes. The separation performance of mixed matrix membranes with respect to humic acid (HA) removal was significantly improved through the addition of ZnO-NPs. The membranes were synthesised by dispersing various amounts of hydrophilic ZnO-NPs (0–3.75 wt.%) into a dope solution containing PES, polyvinylpyrrolidone (PVP) and dimethylacetamide in the appropriate proportions. SEM and AFM were employed to investigate the dispersion of the ZnO-NPs within the polymer matrix and characterise the surface properties of the particles. The pure water flux, HA flux and rejection rate, and the fouling resistance were investigated to evaluate the membrane performance. The characterisation results indicated that all of the PES/ZnO membranes possessed a smaller pore size than that of the pristine PES membrane. The HA rejection rates were observed to increase with the amount of added ZnO. In particul...

Model-based analysis of polymeric membranes performance in high pressure CO2 removal from natural gas

Penetrant-induced plasticization is known to be one of the main challenges of high-pressure membrane separation of CO2 from natural gas. Therefore, a procedure that integrates experimental and mathematical models was developed to analyze the performance of polymeric membranes for removal of CO2 at high feed pressure. A semi-empirical model for estimating plasticization pressure and permeability parameters at plasticization from permeation test data was proposed and tested on more than 90 polymeric membranes. Three model parameters (α1, α2 , and α3) were obtained and used to evaluate membrane performance in terms of plasticization pressure as well as permeability and productivity loss at plasticization pressure. Results from the analysis revealed that this set of parameters can be simply employed to evaluate membrane performance at high pressure.

Optimization of PES/ZnO mixed matrix membrane preparation using response surface methodology for humic acid removal

The application of response surface methodology (RSM) in preparation and optimization of membranes is important in order to reduce the effort and time needed to achieving an optimum performance. RSM was used to develop an optimum polyethersulfone (PES)/ZnO mixed matrix (MM) membrane for humic acid removal. The MMs were synthesized by dispersing various amounts of hydrophilic ZnO nanoparticles (NPs) into a solution containing PES, polyvinylpyrrolidone (PVP) and dimethylacetamide (DMAc). Flat sheet MM membranes were prepared via the phase inversion method using the central composite design (CCD). The effects of four preparation parameters, such as PES, ZnO, PVP weight percentages and solvent evaporation time, were investigated. Pure water flux (PWF), humic acid flux (HAF) and humic acid rejection (HAR) were selected as a model responses. It was shown that PES and PVP were mainly affected on both PWF and HAF. Furthermore, the interaction effect between PES and ZnO-NPs shows a significant effect on PWF, while the quadratic effects of both solvent’s evaporation time and ZnO-NPs weight percentage coupled with the interaction effect between PES and PVP weight percentage shows the most significant parameters that affects HAR. The optimization method was subjected to maximize all of the PWF, HAF and HAR. It was also determined that the optimized membrane can be synthesized from a solution containing 17.25 wt% PES, 3.62 wt% ZnO and 3.75 wt% PVP with 15 s of solvent evaporation time. The optimum values of PWF, HAF and HAR were 222.3 (L/m2 h), 94.7 (L/m2 h), and 96.34%, respectively. Thus, it can be concluded that the CCD technique is capable of optimizing PES-ZnO membrane performance.

Membrane Separation of CO2 from Natural Gas: A State-of-the-Art Review on Material Development

Natural gas (NG) processing and membrane technology are two very important fields that are of great significance due to increasing demand for energy as well as separation of gas mixtures. While NG is projected to be the number one primary source of energy by 2050, membrane separation is a commercially successful competitor to other separation techniques for energy efficient gas separation processes [1]. Most of the NG produced in the world is coproduced with acid gases such as CO2 which need to be removed to increase the caloric value of NG. A comprehensive review of research efforts in CO2 separation from natural gas is required to capture details of the current scientific and technological progresses on the development of new membrane materials with better separation performance, and the improvement of properties of the existing ones. This paper presents the progress that has been achieved in eliminating the limitations that dominate the large scale application of membrane materials at the present time. Various polymers that have been developed to resist plasticization and the method employed to fabricate these polymers are highlighted. Also the range of plasticization pressures (together with corresponding selectivities and permeabilities at these pressures) that have so far been achieved by these fabrication methods is presented. It is believed that this review will serve as a good reference source especially for research in design and development of membrane materials with better resistance to CO2-induced plasticization.

Thin coated adsorbent layer: characteristics and performance study

AbstractAdsorption is the most versatile and widely applied method for water and wastewater treatment due to their economic, simple in operation and efficient process. The aim of this study is to introduce a new approach on adsorption application that are tailored to operator’s requirement and make full use of the existing facilities. The current work will evaluate the feasibility performance of a thin coated adsorbent layer specifically design for colour removal in wastewater. This laboratory-scale experiments reported on the preparation of adsorbent coating layer named Paintosorp. Paintosorp coated on the surface of the glass and tested for its adsorption performance using methylene blue (MB) dye in batch scale. The adsorption process was investigated by varying the initial dye concentration, pH and temperature. The percentage removal of MB was found to be 99% for all concentrations of 50, 100, 150 and 200 mg/l upon achieved equilibrium within 4–20 h for the surface area approximately 0.03 m2 of coated ...

Recent Advancement in Membrane Technology for Water Purification

The present chapter deals with the recent advances in the fabrication of polymer supported nanocomposite membranes for water purification. Fabrication of compositing membrane using conducting polymers in the form of polymer-matrix or surface based thin-film open an innovative way to used nanocomposite materials in diverse field. The improvement of PANI based nanocomposite membranes should be designed by tailored their morphological and physico-chemical properties, thus introducing unique functionalities in order to meet the specific wastewater treatment applications. This review provides a brief description of the current status of PANI nanocomposite membrane which projected higher demand to be applied in water purification systems owing to the significant enhancement on permeability, antifouling and mechanical properties.

Performance of fly ash based polymer gels for water reduction in enhanced oil recovery: Gelation kinetics and dynamic rheological studies

The complexity of well and reservoir conditions demands frequent redesigning of water plugging polymer gels during enhanced oil recovery (EOR). In the present study, we developed coal fly ash (CFA) based gels from polyacrylamide (PAM) polymer and polyethyleneimine (PEI) crosslinker for water control in mature oil fields. The CFA acts as an inorganic additive to fine-tune gelation performance and rheological properties of PAM/PEI gel system. Hence, effects of various CFA (0.5 to 2 wt%), PAM (2 to 8.47 wt%) and PEI (0.3 to 1.04 wt%) concentrations on gelation kinetics and dynamic rheology of pure PAM/PEI gel and PAM/PEI-CFA composite gels were studied at a representative reservoir temperature of 90 oC. Experimental results reveal that gelation time of pure PAM/PEI gel increases with increasing CFA addition. Further observation demonstrates that increasing PAM and PEI concentrations decreases the gelation times of PAM/PEI-CFA composite gels. Gelation time was found to be within 3-120 hours. Understanding the property of reaction order enables better prediction of gelation time. Dynamic rheological data show that viscoelastic moduli (G′ and G″) of various PAM/PEI-CFA composite gels improved better as compared to the pure PAM/PEI gel across the strain-sweep and frequency-sweep tests. SEM analysis of selected samples at 72 hours and 720 hours of gelation activity consolidated gelation kinetics and dynamic rheological results. These polymer gels are excellent candidates for sealing water thief zones in oil and gas reservoirs.