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The interaction between methyl ester sulfonate (MES) surfactant and polyacrylamide (PAM) polymer in alkaline-surfactant-polymer (ASP) flooding due to electrostatic charges and hydrophobicity of both elements at the interface was investigated. In the ASP flooding, sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) were used as alkali. At high PAM concentrations, the strong hydrophobic interaction between the PAM backbone and the carbon chain of MES destabilizes surfactant packing at the interface, increasing interfacial tension (IFT). The higher conductivity value of the ASP slug (15 mS/cm) compared to the alkali-surfactant (AS) slug (7 mS/cm) indicates a strong electrostatic interaction caused by the rapid mobilization of free surfactant molecules across the PAM backbone at the water-oil interface. The lowest IFT value for ASP flooding was 0.28 mN/m. Sand pack flooding tests showed that the optimum PAM concentration in ASP flooding was 1,000 ppm, resulting in a 20–35% oil recovery. A negative effect of PAM on the oil recovery was observed at a higher PAM concentration of 9,000 ppm. IFT and mobility ratios were irregularly related to the oil recovery. At 1,000 ppm PAM, the oil recovery for ASP slug with MES and commercial surfactant sodium dodecyl sulfate (SDS) was 25% and 20%, respectively, indicating that MES is superior to SDS.

The immense demand of plastics worldwide has created a substantial pollution problem that appears not to have an end. New governmental policies and customers preferences towards environmental friendly materials require continued research on biodegradable materials derived from biological resource. In this work, residual palm oil (RPO) recovered from palm oil mill waste effluent was mixed with algae oil (AO) to produce rigid foam polyurethanes (bio-RFPU) at different ratios (AO/RPO) 10/90, 20/80, 30/70, 40/60 and 50/50 by one pot epoxidation and ring opening followed by polymerization with Methylene diphenyl diisocyanate (MDI). Prior to polymerization, significant improvement of 49% was found in the hydroxyl number of the RPO(AO) polyol when AO content was increased from 10 to 50%. Similarly, the homogeneous structure of the cell and the thermal stability of the final bio-RFPU was increased in the samples with 50% AO. Different characterization techniques such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and compression/flexural tests were conducted, and the results presented. The thermal degradation profile of the samples containing 40 and 50% of AO was found to be similar to RFPU with fire retardant and insulation properties. The compressive strength and the biodegradability of the bio-RFPU increased 60% when AO was increased between samples with 10 and 50% AO. Therefore, the developed bio-RFPUs is expected to have great potential as core materials in industrial applications such as sandwich panels as well as in other insulation material.

Artocarpus heterophyllus (jackfruit) leaves (JL) are a waste product that is commonly used as livestock feed. Jackfruit leaves have been revealed to possess many medicinal values such as antioxidant and anti-inflammatory properties. In this study, different drying treatments (shade (SD), sun (SN), and oven (OV)) and ethanol/water ratios (E/W) were investigated to evaluate the impact on drying kinetics, color, and antioxidant properties of jackfruit leaves. Results showed that the Newton model was the best fitted mathematical model for the JL drying kinetics. The moisture effective diffusivities ranged from 2.920 × 10-10 to 6.814 × 10-10 m2/s over the temperature range studied. Shade drying was able to preserve the green pigment better than OV and SN drying treatments. Treatment with ethanol/water ratio at 80% and oven-dried (OV80) revealed the highest phenolic content (195.05 ± 1.21 mg gallic acid equivalent (GAE)/g extract weight (EW)), flavonoid content (11.02 ± 0.17 mg artocarpin equivalent (AE)/g EW), and antioxidant activities (90% scavenging activity and reducing power of 1043.84 ± 5.28 µM trolox equivalent (TE)/g EW) compared to SD and SN treatments. The OV80 also possessed the highest artocarpin, squalene, and β-sitosterol contents determined. The OV80 was selected for improving antioxidant and colour stability, and has the potential to be developed into functional biopolymer production.

In the effort to produce renewable and biodegradable polymers, more studies are being undertaken to explore environmentally friendly sources to replace petroleum-based sources. The oil palm industry is not only the biggest vegetable-oil producer from crops but also one the biggest producers of residual oil that cannot be used for edible purposes due to its low quality. In this paper the development of biopolymers from residual palm oil, residual palm oil with 10% jatropha oil, and residual palm oil with 10% algae oil as additives were explored. Polyols from the different oils were prepared by epoxydation with peroxyacetic acid and alcoholysis under the same conditions and further reacted with poly isocyanate to form polyurethanes. Epoxidized oils, polyols and polyurethanes were analyzed by different techniques such as TGA, DSC, DMA, FTIR and H-NMR. Overall, although the IV of algae oil is slightly higher than that of jatropha oil, the usage of algae oil as additive into the residual palm oil was shown to significantly increase the hard segments and thermal stability of the bio polyurethane compared to the polymer with jatropha oil. Furthermore, when algae oil was mixed with the residual palm oil, it was possible to identify phosphate groups in the polyol which might enhance the fire-retardant properties of the final biopolymer.

This research aimed to improve the stability of Chlorella-Alginate Beads (CABs) by zeolite molecular sieves 13X. Dissolution time of synthesized Zeolite-Algal-Alginate Beads (ZABs) in a chelating agent revealed a significant improvement on the beads stability (78.5 ± 0.5 min) compared to the control beads (51.5 ± 0.5 min) under the optimum conditions of zeolite/alginate (1.5:1), pH 5 and 2% of beads. Monitoring cell growth during 5 days of incubation showed good biocompatibility of zeolite 13X. Scanning electron microscopy (SEM) indicated rough surface and spherical shapes of ZABs. Energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR) of ZABs confirmed the presence of zeolite 13X within the matrix. The zeta potential value of ZABs indicated that the beads were relatively stable. The findings of this research showed that zeolite molecular sieves 13X have the potential to improve the stability of algal-alginate beads compared to common beads.

Owing to the annually increasing market value of pure agarwood oil, the extracted agarwood oil from Aquilaria malaccensis was emulsified in an aqueous solution using non-ionic surfactant (Tween 80). The surfactant concentration of 0.0167% was determined as the critical micelle concentration (CMC) with an interfacial tension value of 0.014 mNm-1. The adsorption of surfactant at the oil/water interface at the CMC value, however, reduced the zeta potential of the emulsified oil from –45 to –43 mV, and increased its size from 85 to 89 nm. Outside of the CMC value, the emulsified oil droplets tended to coalesce, owing to insufficient coverage of the surfactant at oil/water interface and Ostwald ripening. The droplet size distribution and zeta potential value of the emulsified oil droplets produced at the CMC were the most stable over a month of storage. No significant changes in the emulsified droplet size occurred when the pH conditions varied from pH 3 to 10. The emulsified droplets images obtained from transmission electron microscopy analysis showed a reduction in the layer thickness of the surfactant from 30 to 10 nm in acidic condition and 30 to 19 nm in alkaline condition. The agarwood oil emulsification at CMC value enhance the stability of chemically unstable compounds from degradation.

The interest in utilizing algae for wastewater treatment has been increased due to many advantages. Algae-wastewater treatment system offers a cost-efficient and environmentally friendly alternative to conventional treatment processes such as electrocoagulation and flocculation. In this biosystem, algae can assimilate nutrients in the wastewater for their growth and simultaneously capture the carbon dioxide from the atmosphere during photosynthesis resulting in a decrease in the greenhouse gaseousness. Furthermore, the algal biomass obtained from the treatment process could be further converted to produce high value-added products. However, the recovery of free suspended algae from the treated effluent is one of the most important challenges during the treatment process as the current methods such as centrifugation and filtration are faced with the high cost. Immobilization of algae is a suitable approach to overcome the harvesting issue. However, there are some drawbacks with the common immobilization carriers such as alginate and polyacrylamide related to low stability and toxicity, respectively. Hence, it is necessary to apply a new carrier without the mentioned problems. One of the carriers that can be a suitable candidate for the immobilization is zeolite. To date, various types of zeolite have been used for the immobilization of cells of bacteria and yeast. If there is any possibility to apply them for the immobilization of algae, it needs to be considered in further studies. This article reviews cell immobilization technique, biomass immobilization onto zeolites, and algal immobilization with their applications. Furthermore, the potential application of zeolite as an ideal carrier for algal immobilization has been discussed.

Crude palm oil (CPO) and palm-pressed mesocarp fibre oil (PPMFO) consist of minor components such as Vitamin E, phytosterols, squalene, and carotene that play numerous health function in human. However, limitations are present in current separation processes to separate or enrich minor components from plant sources. In this study, interest is focusing on the enrichment efficiency of the minor components from CPO and PPMFO through proposed sequential adsorption-desorption strategy. The strategy started with the adsorption-desorption properties evaluation of six adsorbents. Both Diaion HP20 and Sepabeads SP850 showed better adsorption-desorption properties than silica gel, Florisil, Diaion HP2MG and Amberlite XAD-7HP. Diaion HP20 was selected as the suitable adsorbent to perform a series of selective desorption process using three different solvents: methanol, IPA, and n-hexane in Soxhlet extraction. Vitamin E, phytosterols, and squalene from CPO were obtained in the 1st fraction using methanol solution and their concentration increased from the initial concentration with the enrichment factor (EF) of 3.4, 3.9, and 1.8, respectively, which slightly higher than those minor components obtained from PPMFO, 1.2, 1.8, and 1.4, respectively. The carotene from both CPO and PPMFO was enriched in the 3rd fraction by using n-hexane solution with an enrichment factor of 1.1 and 1.5, respectively. In conclusion, the obtained result revealed the efficiency of the proposed sequential adsorption-desorption strategy to enrich the minor components from CPO and PPMFO.

Dry mangosteen leaves are one of the raw materials used to produce marker ink. However, research using this free and abundant resource is rather limited. The less efficient one-factor-at-a-time (OFAT) approach was mostly used in past studies on plant-based marker ink. The use of statistical analysis and the regression coefficient model (mathematical model) was considered essential in predicting the best combination of factors in formulating mangosteen leaf-based marker ink. Ideally, ink should have maximum color lightness, minimum viscosity, and fast-drying speed. The objective of this study to study the effect of glycerol and carboxymethyl cellulose (CMC) on the color lightness and viscosity of mangosteen-leaves-based marker ink. The viscosity, color lightness, and drying properties of the ink were tested, the significant effect of glycerol and CMC (responses) on ink properties was identified and the prediction model on the optimum value of the responses was developed by using response surface methodology (RSM). The microstructure of mangosteen leaves was analyzed to study the surface morphology and cell structure during dye extraction. A low amount of glycerol used was found to increase the value of color lightness. A decrease in CMC amounts resulted in low viscosity of marker ink. The optimum formulation for the ink can be achieved when the weight percents of glycerol, benzalkonium chloride, ferrous sulphate, and CMC are set at 5, 5, 1, and 3, respectively. SEM micrographs showed the greatest amount of cell wall structure collapse on samples boiled with the lowest amount of glycerol.

Although the commercial prospects for biodiesel have grown, some concern remains with respect to its resistance to oxidative degradation during storage. The presence of double bonds in the molecule induces a high level of reactivity with oxygen when it makes direct contact with air. Consequently, biodiesel storage over extended periods can lead to increased degradation of fuel properties, which can compromise fuel quality. This work used enriched biodiesel samples prepared by enriching palm oil methyl ester (PME) with methyl oleate (MO) at specified volumetric proportions (% v/v) PME80/MO20, PME70/MO30, PME60/MO40, and PME50/MO50 to determine the effects of long storage under two different conditions. The samples were stored either unexposed to air and daylight or exposed to air and daylight for 200 days. At regular intervals, the following physicochemical properties of the samples were measured: kinematic viscosity (KV), acid value (AV), higher heating value (HHV), and peroxide value (PV). Sample...

Potable water from several residential areas on the east coast of Malaysia was filtered using a polyethersulphone (PES) membrane to separate the coarse and fine iron-oxide particles inside the pipelines. The as-received samples consisted of a wide distribution of particle sizes, ranging from 5 μm to 400 nm. The concentration of fine iron-oxide particles inside a distribution system was extremely low. Hence, a specific method is necessary to concentrate and separate the fine particles from the coarse ones. To study the fine particles from the bulk, excess pressure was applied to the membrane filter so that the clogged particles were released into the permeate. A 100 kDa PES membrane was used to separate the particles, because the samples consisted of a wide molecular-weight cut-off range from 89 g/mol goethite (α-FeOOH) to 231 g/mol hematite (Fe2O3). After the filtration process, the size distribution of permeated particles reduced to 550–400 nm. Through X-ray diffraction analysis, numerous polymorphs such as α-FeOOH, Fe3O4, Fe2O3 and maghemite were detected from the samples. The zeta potential value of the permeated particles changed from −18.5 to −13 mV, suggesting that the dispersity of permeated iron-oxide particles became unstable, but remained adequate for electrophoretic deposition (EPD). The fibrous carbon electrode used in the EPD process, could remove up to 87% of the permeated iron-oxide particles compared to solid carbon electrodes (

The potential application of Zeolite 13X-Algal-Alginate Beads (ZABs) for copper biosorption was evaluated and compared with Blank-Alginate Beads (BABs) and Chlorella-Alginate Beads (CABs). Different process parameters were investigated including contact time, pH and initial metallic ion concentration. The findings indicated that the maximum biosorption capacity of ZABs was 85.88 mg/g biosorbent achieved at 180 min, pH 5 and initial metallic ion concentration of 150 mg/l whereas the maximum capacity of 70.02 and 77.32 mg/g biosorbent was obtained for BABs and CABs, respectively. ZABs showed higher stability than BABs and CABs in biosorption-desorption cycles. The kinetic and equilibrium data were analyzed via reaction/diffusion and Langmuir/Freundlich models, respectively. Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR) indicated bonded metal ion to the ABs. Hence, this study confirmed an improvement in stability and biosorption capacity of microalgal-alginate beads.

Biodiesel is a renewable alternative diesel fuel derived from different feedstocks that may have significantly different fatty acid profiles and physiochemical properties. This study aimed to gain further insight into the use of biodiesel in a single-cylinder direct-injection diesel engine. The influences of the properties and compound structure of neat and enriched components of biodiesel on engine performance and exhaust emissions were compared with that of petrodiesel under full load conditions. The enriched blends for testing were prepared by adding methyl oleate (MO) to palm oil methyl ester (PME) at specified volumetric ratios (vol/vol%): PME80:MO20, PME70:MO30, PME60:MO40, and PME50:MO50. Furthermore, various physiochemical properties of neat and enriched blends were evaluated against the ASTM D6751 standard. The impact of key fuel properties of neat and enriched blends associated with the performance of engine and exhaust emissions was discussed. The experimental results exhibited that enriched blends yielded a lower brake torque with higher brake specific fuel consumption (BSFC) than the petroleum diesel because of lower calorific value. Intrinsic reductions in the carbon monoxide (CO) and hydrocarbon (HC) emissions, and exhaust gas temperature (EGT) were also observed, as well as a slight increase in nitrogen oxide (NOx) emission. In addition, enriched blends showed a noticeable improvement in BSFC, with a slight increase in CO emission, HC emission, EGT, and NOx emission over individual PME as a result of lower ignition quality and lower oxygen content. Consequently, biodiesel that possesses more saturated components, and higher oxygen content yields lower EGT, as well as decreased CO, HC, and NOx emissions. However, as a consequence, BSFC is increased.

Biodiesel is a renewable, alternative diesel fuel derived from various oils or fats through transesterification. Biodiesel usually consists of alkyl esters of the parent oil. Palm-oil methyl ester (PME) is a prominent biodiesel in Southeast Asian countries such as Malaysia and Indonesia, which have a surplus production of palm oil. However, given the substantial amount of saturated fatty acids in palm oil, its methyl ester has poor cold-flow characteristics. In the present study, the physicochemical properties of specified blends of technical-grade methyl oleate (MO) and PME, namely, PME80/MO20, PME70/MO30, PME60/MO40, and PME50/MO50 (vol/vol%) were studied. The aim was to determine the optimum blend and achieve better cold-flow properties than neat PME. Differential scanning calorimetry analysis showed that increasing the MO proportion until 50% (vol%, vol%) led to maximum improvements in cloud point and cold filter plugging point, which were reduced to 70.38% and 91.69%, respectively. Important fuel properties (i.e., cetane number (CN), kinematic viscosity, density, gross heating value, net heating value, flash point, oxidation stability, and acid value) were also examined. All fuel properties of PME–MO blends were observed within the specified permissible limits of biodiesel standard (ASTM D 6751).

In this study, the recovery of residual oil from the spikelet of oil palm empty fruit bunches (OPEFB) was conducted. Residual oil was present in the OPEFB due to mechanical processes such as the loading of fruit into the sterilizer cage, sterilization and threshing, in which a certain portion of the oil from the fruitlet was impregnated mainly on the surface of the spikelet rather than on the stalk of OPEFB. The highest residual oil content was found mainly in the small OPEFB (28.49 ± 5.20% dry basis). The oil extraction process was introduced as hydro solvent-assisted steam extraction, which comprises of four main steps, i.e., flooding, injection, soaking and draining. The overall process resulted in above 83% residual oil removal from the spikelet. The proposed method can be an option to be implemented in the palm oil mill because it is a chemical-free, environment-friendly and novel process.