Dayang Radiah Awang Biak

Review of technologies for oil and gas produced water treatment

Produced water is the largest waste stream generated in oil and gas industries. It is a mixture of different organic and inorganic compounds. Due to the increasing volume of waste all over the world in the current decade, the outcome and effect of discharging produced water on the environment has lately become a significant issue of environmental concern. Produced water is conventionally treated through different physical, chemical, and biological methods. In offshore platforms because of space constraints, compact physical and chemical systems are used. However, current technologies cannot remove small-suspended oil particles and dissolved elements. Besides, many chemical treatments, whose initial and/or running cost are high and produce hazardous sludge. In onshore facilities, biological pretreatment of oily wastewater can be a cost-effective and environmental friendly method. As high salt concentration and variations of influent characteristics have direct influence on the turbidity of the effluent, it is appropriate to incorporate a physical treatment, e.g., membrane to refine the final effluent. For these reasons, major research efforts in the future could focus on the optimization of current technologies and use of combined physico-chemical and/or biological treatment of produced water in order to comply with reuse and discharge limits.

An application of the theory of planned behaviour to study the influencing factors of participation in source separation of food waste.

Tremendous increases in biodegradable (food waste) generation significantly impact the local authorities, who are responsible to manage, treat and dispose of this waste. The process of separation of food waste at its generation source is identified as effective means in reducing the amount food waste sent to landfill and can be reused as feedstock to downstream treatment processes namely composting or anaerobic digestion. However, these efforts will only succeed with positive attitudes and highly participations rate by the public towards the scheme. Thus, the social survey (using questionnaires) to analyse publics view and influencing factors towards participation in source separation of food waste in households based on the theory of planned behaviour technique (TPB) was performed in June and July 2011 among selected staff in Universiti Putra Malaysia, Serdang, Selangor. The survey demonstrates that the public has positive intention in participating provided the opportunities, facilities and knowledge on waste separation at source are adequately prepared by the respective local authorities. Furthermore, good moral values and situational factors such as storage convenience and collection times are also encouraged publics involvement and consequently, the participations rate. The findings from this study may provide useful indicator to the waste management authorities in Malaysia in identifying mechanisms for future development and implementation of food waste source separation activities in household programmes and communication campaign which advocate the use of these programmes.

Application of membrane-coupled sequencing batch reactor for oilfield produced water recycle and beneficial re-use.

Oil and gas field wastewater or produced water is a significant waste stream in the oil and gas industries. In this study, the performance of a membrane sequencing batch reactor (MSBR) and membrane sequencing batch reactor/reverse osmosis (MSBR/RO) process treating produced wastewater were investigated and compared. The MSBR was operated in different hydraulic residence time (HRT) of 8, 20 and 44 h. Operation results showed that for a HRT of 20 h, the combined process effluent chemical oxygen demand (COD), total organic carbon (TOC) and oil and grease (O&G) removal efficiencies were 90.9%, 92% and 91.5%, respectively. The MSBR effluent concentration levels met the required standard for oil well re-injection. The RO treatment reduced the salt and organic contents to acceptable levels for irrigation and different industrial re-use. Foulant biopsy demonstrated that the fouling on the membrane surface was mainly due to inorganic (salts) and organic (microorganisms and their products, hydrocarbon constituents) matters.

Stirring time effect of silver nanoparticles prepared in glutathione mediated by green method.

BackgroundThis study aims to investigate the influence of different stirring time for synthesis of silver nanoparticles in glutathione (GSH) aqueous solution. The silver nanoparticles (Ag-NPs) were prepared by green synthesis method using GSH as reducing agent and stabilizer, under moderate temperature at different stirring times. Silver nitrate (AgNO3) was taken as the metal precursor while Ag-NPs were prepared in the over reaction time.ResultsFormation of Ag-NPs was determined by UV–vis spectroscopy where surface plasmon absorption maxima can be observed at 344–354 nm from the UV–vis spectrum. The synthesized nanoparticles were also characterized by X-ray diffraction (XRD). The peaks in the XRD pattern confirmed that the Ag-NPs possessed a face-centered cubic and peaks of contaminated crystalline phases were unable to be located. Transmission electron microscopy (TEM) revealed that Ag-NPs synthesized were in spherical shape. Zeta potential results indicate that the stability of the Ag-NPs is increases at the 72 h stirring time of reaction comparison to GSH. The Fourier transform infrared (FT-IR) spectrum suggested the complexation present between GSH and Ag-NPs. The use of green chemistry reagents, such as peptide, provides green and economic features to this work.ConclusionsAg-NPs were successfully synthesized in GSH aqueous solution under moderate temperature at different stirring times. The study clearly showed that the Ag-NPs synthesized in the long times of stirring, thus, the kinetic of GSH reaction is very slow. TEM results shows that with the increase of stirring times the mean particle size of Ag-NPs become increases. The FT-IR spectrum suggested the complexation present between GSH and Ag-NPs. These suggest that Ag-NPs can be employed as an effective bacteria inhibitor and can be applied in medical field.

Purification of histidine-tagged nucleocapsid protein of Nipah virus using immobilized metal affinity chromatography

Nucleocapsid (N) protein of Nipah virus (NiV) is a potential serological marker used in the diagnosis of NiV infections. In this study, a rapid and efficient purification system, HisTrap 6 Fast Flow packed bed column was applied to purify recombinant histidine-tagged N protein of NiV from clarified feedstock. The optimizations of binding and elution conditions of N protein of NiV onto and from Nickel Sepharose 6 Fast Flow were investigated. The optimal binding was achieved at pH 7.5, superficial velocity of 1.25 cm/min. The bound N protein was successfully recovered by a stepwise elution with different concentration of imidazole (50, 150, 300 and 500 mM). The N protein of NiV was captured and eluted from an inlet N protein concentration of 0.4 mg/ml in a scale-up immobilized metal affinity chromatography (IMAC) packed bed column of Nickel Sepharose 6 Fast Flow with the optimized condition obtained from the method scouting. The purification of histidine-tagged N protein using IMAC packed bed column has resulted a 68.3% yield and a purification factor of 7.94.

Rice bran lipase catalyzed esterification of palm oil fatty acid distillate and glycerol in organic solvent

Rice bran lipase (RBL) was delipidated to enhance its stability in organic solvent and its esterification activity at elevated temperature. The esterification activity of delipidated RBL increased as temperature was increased from 45 to 65°C. The esterification activity of delipidated RBL at 65°C was about 14 times greater than that of the non-delipidated RBL. As temperature was further increased to 75°C, the non-delipidated RBL lost all esterification activity, whereas the delipidated RBL retained approximately 48% of its esterilication activity. The delipidated RBL maintained a relative esterification activity greater than 80% after 16 h of incubation in hexane, whereas the non-delipidated RBL maintained a relative esterification activity of only 50%. A method for production of acylglycerol using delipidated RBL to esterify palm oil fatty acid distillate (PFAD) with glycerol in hexane was successfully developed. The effects of reaction temperatures and type of water removal agents (silica gel and molecular sieve) on the degree of esterification were also examined. A 4 h reaction at 65°C, catalyzed by delipidated RBL and using silica gel as the water removal agent resulted in 53.8% esterification. Thin layer chromatography analysis suggested that the esterified product was primarily comprised of mono-and di-acylglycerols.

Direct recovery of recombinant nucleocapsid protein of Nipah virus from unclarified Escherichia coli homogenate using hydrophobic interaction expanded bed adsorption chromatography

A direct recovery of recombinant nucleocapsid protein of Nipah virus (NCp-NiV) from crude Escherichia coli (E. coli) homogenate was developed successfully using a hydrophobic interaction expanded bed adsorption chromatography (HI-EBAC). The nucleic acids co-released with the recombinant protein have increased the viscosity of the E. coli homogenate, thus affected the axial mixing in the EBAC column. Hence, DNase was added to reduce the viscosity of feedstock prior to its loading into the EBAC column packed with the hydrophobic interaction chromatography (HIC) adsorbent. The addition of glycerol to the washing buffer has reduced the volume of washing buffer applied, and thus reduced the loss of the NCp-NiV during the washing stage. The influences of flow velocity, degree of bed expansion and viscosity of mobile phase on the adsorption efficiency of HI-EBAC were studied. The dynamic binding capacity at 10% breakthrough of 3.2mg/g adsorbent was achieved at a linear flow velocity of 178 cm/h, bed expansion of two and feedstock viscosity of 3.4 mPas. The adsorbed NCp-NiV was eluted with the buffer containing a step gradient of salt concentration. The purification of hydrophobic NCp-NiV using the HI-EBAC column has recovered 80% of NCp-NiV from unclarified E. coli homogenate with a purification factor of 12.5.

Palm Oil Derived Trimethylolpropane Triesters Synthetic Lubricants and Usage in Industrial Metalworking Fluid

Trimethylolpropane triesters are biodegradable synthetic lubricant base oil alternative to mineral oils, polyalphaolefins and diesters. These oils can be produced from trimethylolpropane (TMP) and fatty acid methyl esters via chemical or enzymatic catalyzed synthesis methods. In the present study, a commercial palm oil derived winter grade biodiesel (ME18) was evaluated as a viable and sustainable methyl ester source for the synthesis of high oleic trimethylolpropane triesters (HO-TMPTE). ME18 has fatty acid profile containing 86.8% oleic acid, 8.7% linoleic acid with the remaining minor concentration of palmitic acid, stearic acid and linolenic acid. Its high oleic property makes it superior to produce synthetic lubricant base oil that fulfills both the good low temperature property as well as good oxidative stability. The synthetic base oil produced had a viscosity of 44.3 mm(2)/s at 40°C meeting the needs for ISO 46 oils. It also exhibited an excellent viscosity index of 219 that is higher than some other commercial brands of trimethylolpropane trioleate. Properties of base oil such as cloud point, density, acid value, demulsibility and soap content were also examined. The oil was then used in the formulation of tapping oil and appraised in term of adaptability, stability and field test performance.

Physicochemical Properties of Jatropha Oil-Based Polyol Produced by a Two Steps Method

A low cost, abundant, and renewable vegetable oil source has been gaining increasing attention due to its potential to be chemically modified to polyol and thence to become an alternative replacement for the petroleum-based polyol in polyurethane production. In this study, jatropha oil-based polyol (JOL) was synthesised from non-edible jatropha oil by a two steps process, namely epoxidation and oxirane ring opening. In the first step, the effect of the reaction temperature, the molar ratio of the oil double bond to formic acid, and the reaction time on the oxirane oxygen content (OOC) of the epoxidised jatropha oil (EJO) were investigated. It was found that 4.3% OOC could be achieved with a molar ratio of 1:0.6, a reaction temperature of 60 °C, and 4 h of reaction. Consequently, a series of polyols with hydroxyl numbers in the range of 138–217 mgKOH/g were produced by oxirane ring opening of EJOs, and the physicochemical and rheological properties were studied. Both the EJOs and the JOLs are liquid and have a number average molecular weight (Mn) in the range of 834 to 1457 g/mol and 1349 to 2129 g/mol, respectively. The JOLs exhibited Newtonian behaviour, with a low viscosity of 430–970 mPas. Finally, the JOL with a hydroxyl number of 161 mgKOH/g was further used to synthesise aqueous polyurethane dispersion, and the urethane formation was successfully monitored by Fourier Transform Infrared (FTIR).

Alternative for rapid detection and screening of pork, chicken, and beef using dielectric properties in the frequency of 0.5 to 50 GHz

Dielectric property at high microwave frequency region has been utilized for possible rapid detection and screening of different types of meat, especially for halal authentication. This investigation focused on both raw and sterilized (processed) beef, pork, and chicken samples. Dielectric response that consists of dielectric constant and dielectric loss factor was measured over the range of 0.5 to 50 GHz. All raw and sterilized meat samples could be differentiated by the dielectric values. Two distinct peaks were observed only for both raw and sterilized pork samples at the frequency around 7.43 and 31.19 GHz. These peaks can potentially be linked to compounds that exist only in pork such as DNA, microbes, enzyme, proteins, amino acids, and many others. Dielectric values for sterilized samples were lower than raw samples due to molecule structural changes that occurred in the samples. The dielectric results promise a great potential of utilizing dielectric properties as a rapid on-site detection approach prior to subsequent laborious analysis.