International Journal of Engineering
Volume:31 Issue: 8, Aug 2018

Gelatin is considered as a partially degraded product of collagen and it is a biodegradable polymer which can be used to produce scaffolds for tissue engineering. Three-dimensional, porous gelatin scaffolds were fabricated by thermally induced phase separation and freeze-drying method. Their porous structure and pore size were characterized by scanning electron microscopy. Scaffolds with different pore sizes were obtained by adjusting the concentration of the gelatin. Scaffolds with 3.75% (w/v) gelatin and 5% (w/v) gelatin produced pore range of 100 to 450µm. The average pore size increased with the increase in gelatin concentration. Meanwhile, the properties of the scaffolds in terms of water uptake were studied. The results showed that when the concentration of the gelatin solution was changed from 3.75% to 5%, the water adsorption of the formed scaffolds decreased by 104%. The concentration of gelatin increase caused a reduction in water uptake.

This study analyzed the inhibition activity of Swietenia mahagoni seeds extract on α-glucosidase and α-amylase enzymes inhibition assays. Swietenia mahagoni seeds were extracted by using Supercritical Carbon Dioxide (SC-CO2) extraction at pressures of 20- 30 MPa and temperatures of 40- 60°C. The oil yields obtained were analyzed with α- glucosidase and α- amylase enzymes inhibition assays. All data obtained were expressed as mean ± standard deviation for triplicate experiments. One way analysis was used for statistical significance by using Statistica software version 7.0 (StartSoft, EUA) and IC50 (extract concentration causing 50% enzyme inhibitory) was determined by using GraphPad Prism 6.0 software. Swietenia mahagoni seeds extract have a strong inhibition of α-glucosidase enzyme activity (98.4% ± 0.2) but a moderate inhibition of α- amylase enzyme activity (34.9% ± 1.2). These findings implied that Swietenia mahagoni seeds extract could be an effective natural antidiabetic agent.

Biodiesel which were synthesis from transesterification reaction in the present of heterogeneous base catalyst has been intensively studied over the last decades. This catalyst has an excellent result in producing high percentage conversions of biodiesel without further purification and cleaning process which contribute to the water pollution and high water content in biodiesel product. So, this study was conducted to synthesize and characterize series of heterostructure Ni/Mg/Al2O3 catalysts with different parameters to test their effectiveness towards the catalytic transesterification reaction. Series of Ni/Mg/Al2O3 catalysts were synthesized by wetness impregnation method supported on γ-alumina beads. Three parameters were studied include calcination temperatures, dopant ratios to based and numbers of alumina coating. The activity of the catalyst in transesterification reaction was evaluated at 65ºC of reaction temperature, 3 hours of reaction time, 6% w/w of catalyst loading and 1:24 molar ratio of oil to methanol. The potential catalyst was characterized by N2 Adsorption Analysis, TEM (BIO-TEM) and CO2-TPD. Meanwhile, the performance of the catalyst was evaluated using GC-FID. From the data obtained, Ni/Mg(20:80)/Al2O3 catalyst calcined at 800°C and three times alumina coating have the highest weak and moderate basic sites that contribute to the highest percentage conversion of low grade palm oil to biodiesel compared to others. Besides that, BIO-TEM result shows that the particle was unhomogeneous shape with a mixture of square sheet and one dimensional heterostructure nano-rod particles was observed. The data obtained from CO2-TPD and N2 Adsorption Analysis (NAA) prove that high basicity of the Ni/Mg(20:80)/Al2O3 catalyst (2.80389 mmol/g) and high surface area (125 m2/g) had lead to the 78.53% of biodiesel conversion.

This study explores the potential of titanium oxide impregnated on calcium oxide (CaO-TiO2) as catalyst in transesterification of vegetable palm oil (VPO) to produce biodiesel. The biodiesel yield increased with catalyst calcination temperature and reaction time, and the usage of CaO-TiO2 led to higher biodiesel production when compared to reaction catalyzed by CaO. Biodiesel yield of 93.33% was recorded when CaO-TiO2 was used at optimized reaction conditions. Catalyst characterizations showed that addition of TiO2 to CaO improved the catalytic property by increasing the surface area and strength of basic sites, hence increased the catalytic performance of TiO2-CaO. This study demonstrates the potential of CaO-TiO2 to convert VPO into biodiesel, and the potential of the catalyst in conversion of waste cooking oil into renewable fuel will be studied.

The removal of copper (II) ion by using ultrasound pre-treatment to increase the pores structure and surface area on peanut husk powder via direct sonication (ultrasound probe) and indirect ultrasound (ultrasound bath) at powder level 3.5 W. In previous studies, researchers had applied ultrasound simultaneous with adsorption process. This method is not suitable to treat huge amount of heavy metal in wastewater effluent. In this study, the percentage removal of copper (II) ion and adsorption capacity of direct and indirect ultrasound pre-treated peanut husk powder were compared with untreated peanut husk powder and simultaneous ultrasound adsorption process. The peanut husk powder was characterized by scanning electron microscope (SEM). The effect of variables such as different initial concentration (10-50 mg/L), contact time (0.5–3 h), pH (2–8), and dosage (0.1–0.3 g) were evaluated. 3 h adsorption equilibrium time was required for adsorption of copper (II) ion onto peanut husk surface. The indirect ultrasound pre-treated peanut husk powder has achieved the highest copper (II) ion percentage removal of 99.79% at pH 6 and 0.3 g dosage. It was 57.07% and 19.63% higher than untreated peanut husk powder and simultaneous ultrasound respectively. Both ultrasound pre-treated peanut husk powder shown significant improvement on copper (II) ion removal compared to untreated peanut husk powder and simultaneous ultrasound.

Chromium (Cr) and copper (Cu) are heavy metals known for their dangerous effect towards human health and could enter into human body mainly through ingestion. Over the years, different treatment methods have been used to eliminate heavy metal from raw water source and these include (co)precipitation, coagulation/flocculation, adsorption and ion- exchange. Nonetheless, adsorption is the most prominent method due to its high adsorption capacity and low cost. In this work, graphene oxide-manganese ferrite (GMF) nanomaterials were synthesized and used to remove Cr(VI) and Cu(II) ions from water solution based on adsorption mechanism. The synthesized nanomaterials were characterized using FTIR, BET and TEM prior to use in adsorption process. Batch adsorption studies were carried out to study the adsorption capacity and kinetic properties of the nanomaterials in eliminating two selective heavy metal ions. At optimum pH value, the maximum adsorption capacity for Cr(VI) and Cu(II) are 34.02 mg/g and 66.94 mg/g, respectively. The experimental data revealed that the adsorption isotherm best fitted Langmuir model and followed Pseudo second order.

Despite efficient carbon monitoring system and the commercialization of battery technology for intra-port transportation, port management are found not adopting these environmental yet costly equipments. Port authority who regulates environmental policies lacks leverage to impose tangible reduction on emission through concession. This model integrates sustainability into port equipment expansion theory by quantifying viable equipment electrification profile while observing the constraints of operation, cost and environment. A benchmark emission reduction standard (ERS) is surveyed by Delphi method as environmental demand to determine the electrification of port equipments. The results from Port of Tanjung Pelepas case study suggest an ERS implemented lower than 4% reduction a year is viable to retrofit and replace all electric rubber-tired gantries and prime movers. The simulation model allows informed decision for all port agents to establish viable environmental policies for sustainable port operations.

Membranes offer remarkable attributes such as possessing small equipment footprints, having high efficiency and are environmentally friendly, with carbon membranes progressively investigated for gas separation applications. In this study, carbon tubular membranes for CO2 separationare prepared via the dip-coating method with P84 co-polyimide as the carbon precursor. The prepared membranes were characterized using Thermogravimetric Analysis (TGA), pore structure analysis Brunauer-Emmett-Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR) and pure gas permeation system. The permeation properties of the carbon membranes are measured and analyzed by using CO2, CH4 and N2 gases. The P84-based carbon tubular membrane stabilized at 300°C and featured excellent permeation properties with permeance range of 2.97±2.18, 3.12±4.32 and 206.09±3.24 GPU for CH4, N2 and CO2 gases, respectively. This membrane exhibited the highest CO2/CH4 and CO2/N2 selectivity of 69.48±1.83 and 65.97±2.87, respectively.

Silver-impregnated membrane was facilely prepared by ex situ silver nanoparticles (NPs) blending method using polyethersulfone (PES) as the base polymer. A total of three membranes [F1(S0), F2(S0.5) and F3(S2.0)] were fabricated at different weight percentages of polymer and silver (Ag) loadings to compare their effects on membrane morphological and performance properties. All membrane types were characterized using scanning electron microscope (SEM), energy-dispersive X-ray, Fourier-transform infrared spectroscopy, zeta potential analyzer and contact angle analysis. Characterization data and background theories from the literature were used to study and relate the effect of silver nanoparticles (AgNPs) on the physicochemical properties of the PES/Ag composite membranes with respect to pure water permeability, structural property, surface charge and surface hydrophilicity. Solute rejection performance and antibacterial property of the PES/Ag composite membranes were performed using humic acid (HA) and Escherichia coli (E. Coli) bacteria. The results showed that the membrane with the highest Ag loading (F3) exhibited the highest pure water permeability among all the composite membranes. This phenomenon could be attributed to the morphological changes of the membrane due to the addition of Ag. In this study, contact angle of the membranes showed decreasing trend with the addition of Ag as well as the increase in Ag loading. On the contrary, pore radius of the membranes was found increased with increasing in Ag loading. Owing to this, the F3 membrane demonstrated relatively lower HA rejection (i.e. 89.55%) compared to the pure PES membrane. In terms of the antibacterial performance evaluation, one can confidently state that the membranes with the addition of Ag showed excellent property in biofouling mitigation based on numerous dead E. coli observed on the membrane surface under SEM analysis.

This research addresses the extraction and recovery of nickel ions from real electroplating wastewater using SLM process. The process involves three main phase system which are feed, organic and stripping phase. The feed phase containing the nickel electroplating wastewater whereas the organic phase containing the liquid membrane which was immobilized in the membrane support. The liquid membrane was prepared by dissolving certain concentration of D2EHPA in kerosene which acts as a carrier and diluent, respectively. Meanwhile, the membrane support employed was commercial polypropylene membrane with features of 0.1 mm thickness, 70% porosity and 0.10 µm effective pore size. On the other hand, the stripping phase consisting of sulfuric acid (H2SO4) solution which acted as a stripping agent. Parameters such as carrier and stripping agent concentration and feed phase flowrate were examined to obtain the best condition for the extraction and recovery efficiency of nickel. The results revealed that about 44 and 55% of nickel ions have been successfully extracted and recovered, respectively at the best conditions of 1.0 M of D2EHPA, 3.0 M of H2SO4 and 70 ml/min flowrate of feed phase.

Hydrophobicity properties of graphite and green synthesized graphene (gsG) from exfoliated graphite/GO towards polymer membrane characteristic and properties at different weight percentage concentrations (1, 2, 3, 4 and 5 wt. %) were investigated. PSf/graphite and PSf/gsG membranes were characterized in term of hydrophobicity, surface bonding, surface roughness and porosity. FTIR peaks revealed that membrane with graphite and green synthesized graphene nearly diminished their O-H bonding which was opposite to the graphene oxide peak that show a strong O-H bonding as increased exfoliated time was reported in our previous work. These results were also in line with the contact angle results that showed strong hydrophobicity for the graphite and green synthesized graphene membranes which were then opposed to the exfoliated graphene oxide membrane that has strong affinity towards hydrophilicity properties (as mentioned in previous conducted works). The effect of strong hydrophobicity in modified membrane has result in smoother surface roughness compared to PSf membrane with exfoliated graphene oxide. Results of the surface roughness were in line with the FTIR transition peaks hydrophilicity of exfoliated graphene oxide. It showed that the transition peaks slowly reduced as increasing the formation of green synthesized graphene powder indicating the increment of hydrophobicity properties. The decreased of pure water flux was attributed to the decreased hydrophilicity. From the overall results, it is concluded that the hydrophobicity of PSf/graphite and PSf/green synthesized graphene membrane is not suitable to be applied in water separation whilst be potential for oil and dye separation.

Currently, exchanging trends in the expensive usage of ceramic materials such as alumina, zirconia etc. into economical ceramic raw sources have been studied extensively over the last decade for various technological applications. Despite the fact that this ceramic compound or elements offer a great performance and stability, especially at high temperature and corrosive or acidic conditions, the basic commercial price of this compound which is a little bit higher have hindered the used of these materials. Thus interest in fabricating of bio-ceramic membrane using corn cob ash, an agricultural by product not only offered the development of new low cost materials but also able to enhance better properties and performance. The suitability of corn cob ash as an alternative material for ceramic hollow fiber membrane fabrication (CHFM/CCA) as a main substrate was investigated via combined phase inversion and sintering technique based on several controlled operating parameters. The effects of selected bore fluid (5, 10, 15 and 20 mL/min) and different sintering temperature (800˚C, 900˚C, 1000˚C, 1100˚C) towards membrane structure and properties were observed and studied. Interestingly, analysis of the SEM morphology showed that the potential of the main constituents of corn cob ash which highly consisted of silica, alumina and calcium oxide are able to improve the properties of CHFM/CCA by lowering sintering temperature (1000˚C) as compared to the standard CHFM bodies which normally has sintering temperature higher than 1200 ºC. Thus, the used of corn cob ash not only able to enhance better ceramic properties but also able to reduce sintering temperature. Reduction in energy consumption with slightly reduced sintering temperature also will offer a better sustainable process through recycling abundant waste materials as well as the emphasis on the green resources. In respect, the bio-material of corn cob ash is capable to replace the commercial ceramic membrane materials for membrane applications by considering the availability of this agro waste product as the main crops in most countries in the world.

The disproportionate quantity of ammonia presence in water has led to serious drinkable water scarcity worldwide. The abundant source of mineral and superior cations selectivity has made natural zeolite as a good adsorbent for the ammonia removal. This work aims to fabricate natural zeolite based hollow fibre ceramic membrane (HFCM) via extrusion based phase inversion and sintering techniques for the ammonia removal in wastewater. The physical properties of the fabricated HFCM were investigated through surface morphologies and pure water permeation. The performance of the HFCM for ammonia removal was studied using synthetic wastewater with HFCM prepared at different sintering temperatures. Of all studied sintering temperatures, it was found that 1050 °C was the best fabrication conditions. The membrane also revealed acceptable morphologies (roughness) and water permeation flux of 249.57 L/m2.h to which both contributed to the performance of the HFCM. The ammonia removal using the fabricated HFCM gave an outstanding performance with nearly 90% rejection, which probably is due to the synergistic effect of the two processes in the HFCM system, i.e. adsorption and separation. It was found that natural zeolite based HFCM has a great potential to be developed as a single – step ammonia removal in wastewater treatment.

The effects of different coating time of PANI/Silver onto polysulfone (PSf) membrane surface were investigated based on the morphology, contact angle, surface roughness and rejection towards BSA, pepsin and trypsin. The membrane was prepared by employing the pressure deposition method toward phase inversed membrane. Thus, PANI particles were forced to adhere on membrane surface by pressure driven force. The duration of coated time was taken from 30 mins up to120 mins. However, due to smooth surface of PSf, PANI particle was able to bounce back from the PSf surface. Furthermore, the presence of PANI/Ag were also hard to distinguished on the membrane surface. Clear observation was noticed with the changed of the membrane surface from smooth in to rougher surface. EDS result using SEM data proved the presence of PANI and PANI/Ag on the surface membrane. The hydrophilicity of membrane was proved with decreasing of contact angle test from 75⁰ to 40⁰ for duration0 min until 120 min for membrane coated with PANI. Meanwhile membrane coated with PANI/Ag also show a reduction from 75⁰ to 50⁰. This result was in line with membrane surface roughness which is increased up to 79% after coating with PANI while 90% after coating with PANI/Ag after under effect of 120 min. Higher surface roughness had influenced membrane rejection performance toward BSA. For water rejection test, for PSf membrane show the rejection of 100%, 60.42% and 50% for BSA, pepsin and trypsin. After coating membrane for 30 min, 100%, 90.21% and 77.23% was obtain for coated with PANI and 100%, 92.30% and 80.30% after coating with PANI/Ag. For duration of 120 min, the result shows that coated membrane able to reject 100% BSA, for pepsin and trypsin it shows 96.15% and 87.98% while membrane coated with PANI/Ag, it shows 100% BSA and up to 98.41% and 90.60% pepsin and trypsin protein. In the end, study of membrane performance was improved with presence of PANI and silver on the protein separation process by using deposition method.

A study on the extraction of Acetaminophen (ACTP) which is also known as paracetamol, from aqueous solution by emulsion liquid membrane process using Taylor-Couette Column (TCC) was investigated. An ELM consists of three phase system which are the external, membrane and internal phases. The external phase containing the ACTP aqueous solution to be treated. Basically, the internal and membrane phase form the primary water-in-oil (W/O) emulsion using ultrasonic probe which is to be dispersed in the external phase. In this work, Trioctylamine (TOA), Span 80 and kerosene were used as carrier, surfactant and diluent, respectively in membrane phase. Meanwhile ammonia solution was used as a stripping agent in the internal phase. The influence of several operating conditions such as surfactant and carrier concentration, ultrasonic power, emulsification time, treat ratio, stirring time and stirring speed were investigated. The results showed that the present work proved that the ELM using TCC system was capable to effectively remove about 85 % ACTP from aqueous solutions under optimum conditions of 15 minutes of emulsification time, 6 wt.% of Trioctylamine and Span 80, 20 W power of ultrasonic probe, 5 minutes of extraction time, frequency angular ratio of 1.0 and treat ratio of 3:1.

Subcritical water extraction (SWE) is an alternative technique that implement water as a solvent. The objective of this work was to compare the efficiency of SWE in temperature range from 100ºC to 180ºC at extraction times ranging from 5 to 25 minutes with an ethanolic soxhlet extraction in terms of total phenolic content (TPC), total flavonoid content (TFC) and radical scavenging activity (RSA) from Zingiber zerumbet. Results showed the highest TPC were obtained at 180ºC and 25 min (19.88 mg GAE/g dry sample). The TFC is observed to be slightly fluctuated with time at the respective temperature. The RSA reached the maximum of 83.9 % inhibition at 180ºC and 10 minutes of SWE. A direct linear correlation shows the strong correlation were observed between TPC and RSA(R2=0.910) compared to moderate correlation (R2=0.785) perceived in TFC. It shows that using SWE, phenolic content in Zingiber zerumbet more contributed to its radical scavenging activity compared to its flavonoid content. In comparison to soxhlet extraction, SWE process for Zingiber zerumbet extract is favorable for TPC and antioxidant properties. However the values for TFC in general is lower compared to soxhlet extraction. SWE is a potential alternative extraction process that should be further explored.

The presence of lignin and its degraded products such as tannin and humic acids is the main reason causing the aerobically-treated palm oil mill effluent (AT-POME) to display colour at the point of discharge. In this work, a hybrid method is developed to treat the AT-POME sample that was conventionally treated by biological method. This hybrid method combines coagulation and nanofiltration (NF) membrane process is used to treat the industrial effluent in which the coagulation is conducted prior to NF process. The effects of several variables during coagulation process, i.e., alum concentration, decolouring polymer dosage, cationic polymer dosage and pH on the colour removal and sludge volume production are investigated using response surface methodology (RSM). Optimum variable conditions are chosen to prepare samples with maximum colour rejection and minimum sludge volume for further treatment using the NF membrane process. Under the optimum coagulation conditions (50 mg/L alum, 441 mg/L decolouring polymer, 534 mg/L cationic polymer and pH 9.2), the results showed 92% colour removal with sludge volume as low as 4.1 mL. Further treatment using commercial NF membranes indicated that a permeate sample with complete elimination of colour (almost 100% colour removal) could be produced with reasonably high water flux.

Palm oil mill effluent (POME) poses a great threat to the environment. However, it contains valuable resources such as energy, water and nutrients that could be recovered for sustainable development. Currently, anaerobic digester has been employed to recover the energy potential in POME. However, the presence of suspended solids in the digestate hinders the downstream nutrients recovery process. In that light, cake filtration process appears to be an attractive option for the removal of suspended solids in the digestate. Hence, this paper studied the performance of cake filtration in removing suspended solids at different pressure condition and particle size of perlite. The effectiveness of cake filtration process was evaluated based on the quality of filtrate (turbidity and total suspended solids (TSS)) and filtration flux. In this study, perlites of different particle size distribution (FP3, FW6, FW20, and FW50) were used as both precoat and body feed. The amount of precoat and body feed were chosen as 1 g each. The filtration process was carried out at different pressure condition (2 – 5 bar). It was found that perlite with the finest particle size (FP3) achieved up to 90% of turbidity and TSS removal due to the formation of more compact cake filtration layer. On the other hand, larger perlite FW50 recorded lowest removal efficiency due to its porous cake layer, though this resulted in higher filtration flux. Generally, the increase in pressure drop resulted in higher flux but at the same time led to drastic initial flux decline due to the quick cover up of filtration voids. The outcomes from this study show that it is wise to consider the effect of particle size distribution and pressure drop in order to achieve high clarity of filtrate as well as high filtration flux.

The objective of this work is to develop a new class of nanocomposite ultrafiltration (UF) membranes with excellent solute rejection rate and superior water flux using zeolitic imidazolate framework-8 (ZIF-8) and multi-walled carbon nanotubes (MWCNTs). The effect of ZIF-8 and MWCNTs loadings on the properties of polyvinyldifluoride (PVDF)-based membrane were investigated by introducing respective nanomaterial into the polymer dope solution. Prior to filtration tests, all the membranes were characterized using several important analytical instruments, i.e., SEM-EDX and contact angle analyzer. The addition of the nanoparticles into the membrane matrix has found to increase the membrane pore size and improve its hydrophilicity compared to the pristine membrane. The separation performance of membranes was determined with respect to pure water flux and rejections against bovine serum albumin (BSA) and humic acid (HA).The experimental findings indicated that the nanocomposite membranes in general demonstrated higher permeation flux and solute rejection compared to the pristine membrane and the use of ZIF-8 was reported to be better than that of MWCNTs in preparing nanocomposite UF membranes owing to its better flux and high percentage of solute rejection.

The number of breakthrough pathogenic activity in water distribution network system is constantly increasing day by day especially at level of consumption. Bacterial growth or survival rate often relates to acidity and alkalinity of water. Sudden changes in pH value and temperature indicates a possibility of present bacterial contaminant in aqueous environment. The observation of pH- and temperature-based for tap water supply samples in Pasir Gudang regions therefore was determined. On the basis of the findings, the observed pH value was compared to the recommended range for pH tap and drinking water, which is between 6.5-8.5. A significant spread can be seen among the measured parameters within the range of pH and temperature at 6.00 to 8.65 and 19.20 to 32.00 °C, respectively. There is a statistically significant difference between each sampling regions based on the measured pH value ( 44.79, determined by one-way ANOVA. The pH value and temperature evidence a significant effects by the location of tap water samples near industrial regions. There also appears to be a negative Pearson correlation between the two water parameters in four out of five regions.

The recent development in oil and gas industry increases the production and consumption of oil. The enormous amount of oily wastewater produced is urged to be treated to prevent humanity and environment from being threatened. Membrane technology is an appealing alternative for oily wastewater treatment due to its design simplicity, energy efficiency and environmentally benign approach. In this study, a poly[3-(N-2-methacryloylxyethyl-N,N-dimethyl)-ammonatopropanesulfonate] (PMAPS) incorporated thin film composite (TFC) membrane with excellent anti-fouling properties was fabricated for oil removal from oily wastewater through forward osmosis process. PMAPS was blended with the polyethersulfone (PES) dope solution and casted into PES support layer. The TFC was fabricated via interfacial polymerization (IP) technique to form a thin film polyamide (PA) layer atop of a PES support layer. The PMAPS incorporated TFC membranes has been characterized for their morphology, surface hydrophilicity and charges. The incorporation of PMAPS was compatible with the PES polymer matrix hence lead to defect-free thin film formation. Prior to the hydrophilicity of PMAPS, the resultant TFC membrane exhibited a high water flux of 10.3±0.3 L/m2.h and oil flux of 9.6±0.8 L/m2.h, reverse salt flux of 1.3±0.4 L/m2.h under FO mode using emulsified oily solution as feed solution and 2M NaCl as draw solution using active layer-feed solution (AL-FS) orientation. 99% of oil rejection was obtained. Also, PMAPS incorporated TFC membrane was able to outperform neat TFC membrane with lower fouling propensity for oily waste treatment.