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The application of pervaporation (PV) as a membrane-based separation process for the recovery of dilute organic solutes has become a promising alternative to conventional distillation due to its easy scaleup, energy-saving, process continuity. The present study aims at the modelling of mass transfer during the pervaporation process for ethanol recovery from ethanol/water mixture using a solution-diffusion model at different concentrations (5–20%), and different temperatures (30–60 °C). The results revealed that the estimated values of ethanol reference permeance and water reference permeance were respectively Q0eth = 11.77 ± 0.10 g/m2 h kPa and Q0water = 13.31 ± 0.16 g/m2 h kPa. It was also found that the estimated value of ethanol activation energy (Ea(eth)) was 60.40 ± 6.40 kJ/mol whereas the estimated value of water activation energy (Ea(w)) was 56.09 ± 5.05 kJ/mol. The validation of the suggested solution-diffusion model was assessed in terms of mean absolute percentage error (MAPE) using fermentation broth where it showed high accuracy with a low value of MAPE for the ethanol flux (MAPE = 2.8%), water flux (MAPE = 2%), total flux (MAPE = 3.2%). These findings suggest the solution-diffusion model as an efficient tool for optimizing and controlling the pervaporation process when it is coupled with continuous alcoholic fermentation for bioethanol production.

This study aimed to optimize the removal of Cu(II) ions from an aqueous solution using a

Despite the advantages of continuous fermentation whereby ethanol is selectively removed from the fermenting broth to reduce the end-product inhibition, this process can concentrate minor secondary products to the point where they become toxic to the yeast. This study aims to develop a new mathematical model do describe the inhibitory effect of byproducts on alcoholic fermentation including glycerol, lactic acid, acetic acid, and succinic acid, which were reported as major byproducts during batch alcoholic fermentation. The accumulation of these byproducts during the different stages of batch fermentation has been quantified. The yields of total byproducts, glycerol, acetic acid, and succinic acid per gram of glucose were 0.0442, 0.023, 0.0155, and 0.0054, respectively. It was found that the concentration of these byproducts linearly increases with the increase in glucose concentration in the range of 25–250 g/L. The results have also showed that byproduct concentration has a significant inhibitory effect on specific growth coefficient (μ) whereas no effect was observed on the half-velocity constant (Ks). A new mathematical model of alcoholic fermentation was developed considering the byproduct inhibitory effect, which showed a good performance and more accuracy compared to the classical Monod model.

Dissolution of polyphenolic compounds from condensed tannins powder from wattle species was carried out using water-glycerol mixtures and sulfuric acid (H2SO4) as a catalyst. The study focused on parameters that can be adjusted to maximize the dissolution. The parameters of the dissolution process (mass of glycerol, mass of tannin powder, temperature and stirring time) were screened using a one factor at a time (OFAT) technique, while the optimum conditions were obtained using response surface methodology (RSM). Effects of the mass of glycerol, mass of tannin powder, temperature, and stirring time used on the percentage of dissolved tannin residue was apparent. The amount of undissolved tannin was used as the direct measurement in this study since there is no established method available to test tannin dissolution in water-glycerol-acid solution. The result from RSM based on 30 experimental sets showed that the lowest undissolved tannin powder value was 10% when 75 grams of tannin powder was mixed with 13.56 grams of glycerol, 86.44 grams of water, and 1.00 grams of sulphuric acid, at 75 °C temperature and 44.13 minutes stirring time.

A versatile synthetic approach for development of highly fluorescent nitrogen-doped carbon dots (N-CDs) from carboxymethylcellulose in the presence of linear polyethyleneimine (LPEI) has been developed. According to single factor method, central composite design incorporated with response surface methodology matrix was applied to find and model optimal conditions for the temperature (220–260 °C), duration (1–3 h) and LPEI weight (0.5–1.5%). The statistical results show that duration was the most significant parameter for efficient carbonization conversion rate in comparison with temperature and LPEI weight. The reduced cubic model (R2 = 0.9993) shows a good correlation between the experimental data and predicted values. The optimal variables were temperature of 260 °C, duration of 2 h and LPEI weight of 1%. Under these conditions, quantum yield of up to 44% was obtained. The numerically optimized N-CDs have an average size of 3.4 nm with graphitic nature owing to the abundant amino species incorporated into the carbon core framework. The blue-green N-CDs possess emission dependent upon the solvent polarity, wide pH stability with enhanced emission in an acidic environment. Impressively, the N-CDs show long-shelf-life for up to 1 year with no noticeable precipitation. The N-CDs were able to recognize a high concentration of Fe3+ ions with a detection limit of 0.14 μM in acidic solution owing to the special coordination for Fe3+ to be captured by electron-donating oxygen/ amino groups around N-CDs. Moreover, the N-CDs can also be used as a new kind of fluorescent ink for imaging applications.

The aim of this study is to assess the curing behaviour and thermal properties of phenol–formaldehyde (PF) adhesives with different degree of tannin substitution using several thermal analysis techniques. Tannin from Acacia mearnsii bark was copolymerized with PF to form a bonding agent for plywood. The resin mixture was heated at 50 °C prior to adding 40% w/w tannin solution, followed by a continuous stirring for 2 h. The amounts of tannin substitution were 20%, 30% and 40% (w/w of PF solids) and 100% PF were used as control. The study shows that the addition of tannin quickened the gel time of the resin notably, parallel with the increase in viscosity of the resin. The dry shear bond strength of the tannin phenol–formaldehyde (TPF) co-polymer ranged between 1.71 and 2.58 MPa as compared to 3.41 MPa for PF. At higher addition of tannin, the shear bond strength reduced significantly predominantly the 40% tannin substitution. Formulation containing 20% tannin was found comparable to that of neat PF. Thermal test revealed that TPF starts to degrade at a lower temperature than PF resin. All TPF resins started to cure at about 125 °C and peaked at 160 °C compared to PF that began to cure at 145 °. The DMA of the resin showed an increase in the resin stiffness with an addition of tannin. These results imply that even though TPF starts to degrade at lower temperature, the cured TPF is relatively stronger than pure PF.

Characteristics and performances of a blended jatropha bio-epoxy/epoxy as a matrix in carbon fiber reinforcement was studied. The amount of bio-epoxy was arranged from 0 wt%, 25 wt%, 30 wt%, 40 wt%, and 50 wt% of the total matrix. Several analyses were performed to characterize and observe their performance. Fourier transform infrared spectroscopy, thermal analysis, physical characteristics, flammability, and soil burial were conducted, as well as mechanical tests. The results showed that introducing bio-epoxy in the matrix changed characteristics and increased or decreased their performance. Blending more than 25 wt% of bio-epoxy led to improved thermal stability between 280 °C to 350 °C and better biodegradability. However, tensile and flexural strength as well as modulus of elasticity decreased once the proportion of bio-epoxy was greater than 25 wt%. The paper proposed an optimal amount of jatropha bio-epoxy so that an alternative biocomposite application could be introduced to minimize carbon footprint in the environment.

The need for the sensing of environmental pollutants cannot be overemphasized in the twenty-first century. Herein, a sensor has been developed for the sensitive and selective detection of copper (Cu2+), lead (Pb2+) and cadmium (Cd2+) as major heavy metals polluting water environment. A screen-printed carbon electrode (SPCE) modified by fluorescent carbon dots (CDs) and gold nanoparticles (AuNPs) was successfully fabricated for sensing Cu2+, Pb2+ and Cd2+. Differential pulse voltammetry (DPV) and cyclic voltammetry (CV) were deployed for the analysis of ternary analytes. CV was set at a potential range of − 0.8 to + 0.2 V at a scan rate of 100 mV/s, and DPV at a potential range of − 0.8 to + 0.1 V, scan rate of 50 mV/s, pulse rate of 0.2 V and pulse width of 50 ms. DPV technique was applied through the modified electrode for sensitive and selective determination of Cu2+, Pb2+ and Cd2+ at a concentration range of 0.01 to 0.27 ppm for Cu2+, Pb2+ and Cd2+. Tolerance for the highest possible concentration of foreign substances such as Mg2+, K+, Na+, NO3−, and SO42− was observed with a relative error less than ± 3%. The sensitivity of the modified electrode was at 0.17, 0.42 and 0.18 ppm for Cd2+, Pb2+ and Cu2+, respectively, while the limits of detection (LOD) achieved for cadmium, lead and copper were 0.0028, 0.0042 and 0.014 ppm, respectively. The quality of the modified electrode for sensing Cu2+, Pb2+ and Cd2+ at trace levels is in accordance with the World Health Organization (WHO) and Environmental Protection Agency (EPA) water regulation standard. The modified SPCE provides a cost-effective, dependable and stable means of detecting heavy metal ions (Cu2+, Pb2+ and Cd2+) in an aqueous solution.

The valorization of cellulose-based waste is of prime significance to green chemistry. However, the full exploitation of these lignocellulosic compounds to produce highly luminescent nanoparticles under mild conditions has not yet been achieved. In this context, we convert low-quality waste into value-added nanomaterials for the removal of Cu(II) from wastewater. Carboxymethylcellulose (CMC), which was derived from empty fruit bunches, was selected for its high polymerization index to produce luminescent nitrogen-doped carbon dots (N-CDs) with the assistance of polyethylene glycol (PEG) as a dopant. The optimum N-CD sample with the highest quantum yield (QY) was characterized using various analytical techniques and the results show that the N-CDs have great crystallinity, are enriched with active sites and exhibit a long-shelf life with an enhanced QY of up to 27%. The influence of Cu2+ concentration, adsorbent (N-CDs) dosage, pH and contact time were investigated for the optimal adsorption of Cu2+. The experiments showed the rapid adsorption of Cu2+ within 30 min with a removal efficiency of over 83% under optimal conditions. The equilibrium isotherm investigation revealed that the fitness of the Langmuir isotherm model and kinetic data could be well explained by the pseudo-second order model. Desorption experiments proved that N-CDs can be regenerated successfully over five adsorption–desorption cycles owing to the ability of ascorbic acid (AA) to reduce the adsorbed nanocomplex into Cu+. The rapid adsorption property using low-cost materials identifies N-CDs as a superior candidate for water remedy.

New ways of synthesizing organic-based fluorescent carbon dots (CDs) are required in environmental application. This is crucial for mitigation and control of pollutants without increasing the risk of releasing byproduct pollutants as the case with non-organic (metallic) quantum based substrate. Notably, this study provides current research on sustainable synthesis of CDs and their applications through analytical concept of recent and advance techniques for efficient and optimized processes. New scrutinized methods of synthesis and applications of CDs are beneficial and essential to optimize the state-of-art practices. The value distilled in this study adds to the field of sustainable production and application of CDs.

Hydro-distillation (HD) has been widely used in the extraction of essential oil, yet it is a low efficient method that consumes time and energy. In this work, A. malaccensis’ oils have been extract...

Dielectrophoresis (DEP) is one of an alternative way for cell separation. It has mainly been limited to processing small volumes due to constrain in fabrication of microelectrode over large surface areas. This work incorporated the wire cloth electrode fabricated using textile technology into a high throughput chamber experiment. The plain-weave wire cloth consists of 71µm stainless steel wires as the microelectrode arrays hold together by polyester yarn warp. This work determines the cell separation yield with parameters on applied voltage, flow rate and cell concentration as well as its optimized variables on the chamber width of 1.2cm and 2.5cm. The optimum voltage achieved was 30Vpk-pk, with flow rate of 3.5 ml/min and maximum cell concentration of 2.08x107 cells/ml. In chamber width comparison, 1.2cm width chamber gives better total percentage yield of 96% than the 2.5cm width chamber of 85% total percentage yield.

This research demonstrates an economical and efficient reduction of carbon foot print. Tapioca powder as a source of organic carbon was utilized in the synthesis of carbon dots through optimization of the synthesis parameters such as temperature, dosage and time. Photoluminescent quantum yield (PLQY) was obtained under the visible region of 340 nm at 34.9%, which was achieved without dopants such as sulfur and nitrogen that are popularly used to increase the value of photoluminescence. The characterization of carbon dots such as FTIR and HrTem, were carried out for the analysis of functional groups, particle sizes (1‐5 nm) and shapes (quasi‐spherical). The high carbon‐carbon bonds and oxygen groups detected in FTIR analysis validates the basis of fluorescence of carbon dots and also presence of hydroxyl (OH), carboxylic acids (COO), and other vital functional groups (C=O, C−O‐C, C−H). These characteristics makes tapioca based carbon dots suitable for application in the fields of environmental studies including sensitive detection and absorbance of pollutants in water and bio imaging in health sciences.

In this study, a techno-economic assessment of an on-farm biogas system using an anaerobic biofilm reactor utilizing cow manure as a fermentation substrate was evaluated. A projection model was developed using Microsoft Excel software with three outputs, the size and dimension of a bioreactor, experimental microbial kinetic studies, and the economic studies based on the experimental results. Characterization analysis of cow manure wastewater showed the total solid (TS), total volatile solid (TVS), total carbohydrate (TC), chemical oxygen demand (COD), and pH values which were 10.95 g/L, 8.65 g/L, 6.65 g/L, 57.80 g/L, and 7, respectively. Using the modified Gompertz equation for the microbial studies, it was found that, at 37 °C and 20 days hydraulic retention time (HRT), the biogas yield was 934.54 mL/gVS, the volume of biogas produced was 11.28 m3/d, and 22.56 kWh of electricity was generated. The Gompertz prediction helps to determine the optimal HRT for the system so that the microorganisms are at their optimum stage to produce biogas. The economic analysis was done, and the results illustrated that, when the rate of cow manure produced was at 55 L/day.cow, the net present value (NPV) was RM 611,936.09, with a 13% internal rate of return (IRR), 0.14 return on investment (ROI), and 7.02 years of payback period (PP). By developing a techno-economic assessment that included all the necessary parameters such as sizing of the bioreactor, microbial kinetic studies, and economics of the plant, farmers could easily implement the system into their farms. This model showed that the anaerobic digestion system utilizing an attached biofilm with cow manure as a fermentation inoculum and substrate was applicable on an industrial scale to generate electricity and reutilize to the farm, at the same time generating additional income from the production of fertilizer.

As a remedy for environmental pollution, a versatile synthetic approach has been developed to prepare polyvinyl alcohol (PVA)/nitrogen-doped carbon dots (CDs) composite film (PVA-CDs) for removal of toxic cadmium ions. The CDs were first synthesized using carboxymethylcellulose (CMC) of oil palms empty fruit bunch wastes with the addition of polyethyleneimine (PEI) and then the CDs were embedded with PVA. The PVA-CDs film possess synergistic functionalities through increasing the content of hydrogen bonds for chemisorption compared to the pure CDs. Optical analysis of PVA-CDs film was performed by ultraviolet-visible and fluorescence spectroscopy. Compared to the pure CDs, the solid-state PVA-CDs displayed a bright blue color with a quantum yield (QY) of 47%, they possess excitation-independent emission and a higher Cd2+ removal efficiency of 91.1%. The equilibrium state was achieved within 10 min. It was found that adsorption data fit well with the pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption uptake was 113.6 mg g&minus, 1 at an optimal pH of 7. Desorption experiments showhe that adsorbent can be reused fruitfully for five adsorption-desorption cycles using 0.1 HCl elution. The film was successfully applied to real water samples with a removal efficiency of 95.34% and 90.9% for tap and drinking water, respectively. The fabricated membrane is biodegradable and its preparation follows an ecofriendly green route.

A method that delivers a high yield and excellent quality of essential oil, which retains most of its value-added compounds, and undergoes least change after the extraction process, is greatly sought after. Although chemical free methods are acceptable, they call for an extensive processing time, while the yield and quality from these methods are often disappointing. This work utilizes subcritical water technology to address these issues. In this undertaking, essential oil was extracted from Aquilaria malaccensis wood by way of subcritical conditions, and characterized through gas chromatography/mass spectroscopy (GC/MS). Optimization through response surface methodology revealed temperature to be the most critical factor for the extraction process, while the optimum conditions for temperature, sample-to-solvent ratio, and time for subcritical water extraction was revealed as 225 &deg, C, 0.2 gr/mL, and 17 min, respectively. The subcritical water extraction technique involves two simultaneous processes, which are based on good fitting to the two-site kinetic and second order model. In comparison to the hydrodistillation method, GC/MS results indicated that the quality of A. malaccensis&rsquo, wood oils, derived through the subcritical water technique, are of significantly better quality, while containing many constructive value-added compounds, such as furfural and guaiacol, which are useful for the production of pesticides and medicines. Pore size, functional groups, and morphology analysis revealed the occurrence of substantial damage to the samples, which facilitated an improved extraction of bio-products. In comparison to conventional methods, the use of the subcritical method not only involves a shorter processing time, but also delivers a higher oil yield and quality.

Heat explosions are sometimes observed during the synthesis of phenol formaldehyde (PF) resin. This scenario can be attributed to the high latent heat that was released and not dissipated leading to the occurrence of a runaway reaction. The synthesis temperature and time played important roles in controlling the heat release, hence preventing the resin from hardening during the synthesis process. This study aims to assess the rheological and viscoelasticity behaviors of the PF resin prepared using paraformaldehyde. The prepared PF resin was designed for laminate applications. The rheological behavior of the PF resin was assessed based on the different molar ratios of phenol to paraformaldehyde (P:F) mixed in the formulation. The molar ratios were set at 1.00:1.25, 1.00:1.50 and 1.00:1.75 of P to F, respectively. The rheological study was focused at specific synthesis temperatures, namely 40, 60, 80 and 100 &deg, C. The synthesis time was observed for 240 min, changes in physical structure and viscosity of the PF resins were noted. It was observed that the viscosity values of the PF resins prepared were directly proportional to the synthesis temperature and the formaldehyde content. The PF resin also exhibited shear thickening behavior for all samples synthesized at 60 &deg, C and above. For all PF resin samples synthesized at 60 &deg, C and above, their viscoelasticity results indicated that the storage modulus (G&prime, ), loss modulus(G&Prime, ) and tan &delta, are proportionally dependent on both the synthesis temperature and the formaldehyde content. Heat explosions were observed during the synthesis of PF resin at the synthesis temperature of 100 &deg, C. This scenario can lead to possible runaway reaction which can also compromise the safety of the operators.

Colourants contained in palm oil mill effluent (POME) are recalcitrant and carcinogenic in nature. The commonly applied ponding treatment methods have been reported inefficient for remediating the concentration of the colourants before discharge. The need for sustainable and efficient treatment technique is crucial in order to preserve the environment. In this view, this study reported the first attempt to decolourize POME using a proliferate Klebsiella Pneumonia ABZ11 at varied inoculum sizes of 5-25 % (v/v), initial colour concentration (650-2600 ADMI) and treatment time of 5-40 h. The treatment conditions were optimized using Response Surface Methodology. At optimal conditions of 20 % (v/v) inoculum size, initial-colour concentration of 2600ADMI, initial pH of 7 and 35 h treatment retention time, over 80.40 % colour removal was achieved with insignificant disparity compared with the model predicted value of 81.538 %. Also, the Monod model excellently described the decolourization kinetic process with 0.9214 coefficient of correlation (R2), and the calculated maximum growth (μ_max) and half-saturation constant (Ks) were 7.023 d-1 and 340.569 ADMI.d-1, respectively. This study revealed that the Klebsiella Pneumonia ABZ11 was highly prolific and such feature may favours a synergistic biodegradation process.

This study focused on developing a hydrophilic hybrid polyvinylidene fluoride (PVDF)-polyethylene glycol (PEG) hollow membrane by incorporating Nano-magnesium oxide (NMO) as a potent antifouling mediator. The Nano-hybrid hollow fibers with varied loading of NMO (0 g, 0.25 g, 0.50 g, 0.75 g and 1.25 g) were spun through phase inversion technique. The resultants Nano-hybrid fibers were characterized and compared based on SEM, EDX, contact angle, surface zeta-potential, permeability flux, fouling resistance and color rejection from palm oil mill effluent (POME). Noticeably, the permeability flux, fouling resistance and color rejection improved with the increase in NMO loading. PVDF-PEG with 0.50 g-NMO loading displayed an outstanding performance with 198.35 L/m2&middot, h, 61.33 L/m2&middot, h and 74.65% of water flux, POME flux and color rejection from POME, respectively. More so, a remarkable fouling resistance were obtained such that the flux recovery, reversible fouling percentage and irreversible fouling percentage remains relatively steady at 90.98%, 61.39% and 7.68%, respectively, even after 3 cycles of continuous filtrations for a total period of 9 h. However, at excess loading of 0.75 and 1.25 g-NMO, deterioration in the flux and fouling resistance was observed. This was due to the agglomeration of nanoparticles within the matrix structure at the excessive loading.

The materials and substances required for sustainable water treatment by adsorption technique, are still being researched widely by distinguished classes of researchers. Thus, the need to synthesize substances that can effectively clean up pollutants from the environment cannot be overemphasized. So far, materials in bulk forms that are rich in carbon, such as biochar and varieties of activated carbon have been used for various adsorptive purposes. The use of bulk materials for such purposes are not efficient due to minimal surface areas available for adsorption. This study explores the adsorption task at nano dimension using carbon dots (CDs) from tapioca. The properties of carbon structure and its influence on the adsorptive efficacy of carbon nanoparticles were investigated by energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HrTEM), and atomic force microscopy (AFM). The results implied carbon present in CDs are good adsorbents for effective adsorption of heavy metal ions (lead) with removal efficiency of 80.6% in aqueous environment. The adsorption process as explored by both Langmuir and Freundlich isotherms have proven favorability of the adsorption process. Langmuir form two and three have correlation coefficients R2 at 0.9922 and 0.9912, respectively. The Freundlich isotherm confirms CDs as having defined surface heterogeneity and the exponential distribution of active sites. The adsorption of lead unto CDs obeyed the second order kinetic model with coefficient of determination, R2 of 0.9668 and 0.9996 at an initial lead concentration of 20 mg/L and 100 mg/L, respectively. The findings validated the efficiency of CDs derived from tapioca as an excellent material for further utilization in the environmental fields of wastewater pollution detection and clean up, bio-imaging, and chemical sensing applications.

Bio-resins are bio-based materials derived from vegetable resources, especially from vegetable seed oils. It is widely known that bio-resources are renewable, highly available, and sustainable. Resins and most polymers are largely derived from petroleum-based sources that are known to pose chemical risks. Resins have practical applications in printing inks, plasticisers and diluents, as well as in coating materials. Vegetable oils possess a large number of oxirane groups, which are essential for epoxidation to occur, resulting in the production of bio-resins. This undeniably serves as a promising candidate for competing with fossil-fuel-derived petroleum-based products. Thus, the aim of this review paper is to highlight aspects related to the production of bio-resins, including the chemical route of vegetable oil epoxidation process and its influencing factors, the reaction kinetics, bio-resins and the physico-chemical and mechanical properties of bio-resins, along with their applications. The resins industry has seen some remarkable progress towards the commercialisation of several bio-resins originating from vegetable oils, such as soybean oil, castor oil, and linseed oil. This success has undoubtedly intensified further efforts in fields related to bio-resin applications. Research and development is ongoing with the aim of customising a feasible formulation for the synthesis of bio-resins with the desired properties for catering to various applications

Acid hydrolysis is one of the most important processes for biomass conversion into value-added chemicals. However, hydrolysis of biomass requires an effective pretreatment to make this reaction more efficient. Ultrasonic technology, is one of the pretreatment used in biomass conversion before being subjected to hydrolysis reaction. In this study, the effect of ultrasonic on the conversion of oil palm mesocarp fibre into levulinic acid (LA) was investigated. Levulinic acid, can be used as a chemical intermediate for many applications. Two different pretreatments were explored. For acid pretreatment, samples were pretreated at different sulfuric acid concentration and temperatures (60 °C, 80 °C and 100 °C). For ultrasonic-assisted acid pretreatment, the samples were pretreated at different sonication power (40%, 60% and 80%). The highest yield of LA was obtained during hydrolysis from the sample acid pretreated at temperature at 100 ⁰C using 6 % acid solution (3.93%). While using ultrasonication, the highest yield of LA was around (3.11%) obtained at 80% power and 6% acid solution. Hydrolysis was also conducted without removing liquor (liquid solution) from the biomass after each pretreatment. The results after hydrolysis showed a remarkable improvement of LA yield at 20.54% obtained from sample pretreated with H2SO4 acid at 100 ⁰C and 6% (v/v). These results suggest that acid pretreatment at high temperature is effective in improving the yield of LA from the biomass. The use of ultrasonication did not improve the hydrolysis as expected.

Subcritical water extraction (SWE) of essential oil (EO) from Citrus hystrix DC. leaves was optimized using response surface methodology (RSM), involving factors of particle size (0.5–1) mm, sample-to-solvent ratio (0.025–0.175) g/mL, extraction temperature (140−180) °C, and extraction time (20−40) minutes. Thus, an optimal EO yield of (2.14 ± 0.03) % (w/w) was obtained at 0.75 mm, 0.025 g/mL, 174 °C, and 29 min. SWE was found to yield significantly higher EO than the conventional hydrodistillation, within a shorter time. The regression model was established, presenting a significant quadratic correlation (R2 = 0.97) and adequate for predictions. SWE at 160 °C and 180 °C yielded 36 compounds, with isopulegol-dominant, exceeding SWE at 140 °C (21 compounds) and hydrodistillation (25 compounds). SWE with tunable temperatures not only improved the quantity of EO but was also capable of enhancing the quality because more EO compounds were extracted, offering diverse functionalities to nutraceutical sectors.

The performance of plastic optical fiber sensors in detecting nitro aromatic explosives 1,4-dinitrobenzene (DNB) have been investigated by fluorescence spectroscopy and analyzed by using fluorescence quenching technique. The plastic optical fiber utilized is 90 degrees cut tip and dip-coated with conjugated polymer MEH-PPV poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] thin films for detection conjugants. The thicknesses of the MEH-PPV coating were varied to improvise the sensitivity whilst slowly reducing the fluorescence intensity. It was shown that fluorescence intensity from thinner film decreased by (82% in 40 s) in the presence of DNB signifying an improvement of 28% reduction with time 13 s less than that of the thicker film.

A new commercial cationic polyelectrolyte chitosan (CM), obtained from the waste of mushroom production, was examined using models of water and wastewater namely kaolin and palm oil mill effluent (pome). As it is biocompatible, widely available, and economically feasible, chitosan mushroom has high potential to be a suitable replacement for alum. Also, it can be a promising alternative to chitosan obtained traditionally from Crustaceans due to its higher zeta potential and homogeneity based on the raw material required for its production. A wide range of coagulant dose (5-60 mg l-1) and wastewater pH (2-12) were taken into account to find the optimal conditions of coagulation. The optimal doses are 10 and 20 mg l-1 at best pH (11 and 3) when treated with kaolin and palm oil mill effluent, respectively, while 1200 mg l-1 of alum was not enough to reach the efficiency of chitosan mushroom. On the other hand, the optimum dose of chitosan mushroom (20 mg l-1) at pH 3 of pome produced (75, 73, and 98%) removal of chemical oxygen demand (COD), biological oxygen demand (BOD), and total suspended solids (TSS), respectively. The significant potential of chitosan mushroom was proved by zeta potential measurement. Indeed, it possesses the highest zeta potential (+70 mV) as compared to the traditional chitosan produced from crustaceans. In short, chitosan mushroom as a biocoagulant is eco-friendly and it enhances water quality that meets the requirements of environmental conservatives.

Alternative natural coagulants from Jatropha curcas seed and press cake were investigated for coagulative behaviors and abilities to treat real wastewater. The characterization of the seed and press cake was done by proximate analysis while characterization on extracts which contain the active coagulant agent was conducted using FTIR, amino acid analysis, and zeta potential. The coagulation performance was evaluated using Jar Floc test on palm oil mill effluent. Proximate analysis indicated that Jatropha seed contained more protein (54%) than press cake (28%). Through HPLC analysis, 18 types of amino acid were detected in Jatropha curcas (JC) seed and press cake extracts. FTIR results confirmed the functional groups that existed in all the amino acids. The zeta potential of the extracts was positive at pH 4, respectively. Hence, the mechanism of coagulation at pH 4, adsorption and interparticle bridging dominates. Dosages of 140 mg L−1 of Jatropha seed and 120 mg L−1 of press cake were required to treat 3500 NTU of POME to give 99 and 93% turbidity removal, respectively. Jatropha seed gave maximum turbidity removal at pH 3, while press cake at pH 2. The final pH of the treated POME was not altered greatly and the sludge produced was lesser in comparison to alum. In conclusion, the protein was the compound responsible for Jatropha coagulating behavior and its ability to treat real wastewater is promising. © 2017 American Institute of Chemical Engineers Environ Prog, 2017

This study aimed to model the kinetic of hydro-distillation of Aquilaria malaccensis leaves oil in order to understand and optimize the extraction process. In addition, this study, for the first time, aimed to identify the chemical compositions of the A. malaccensis leave-oil. By assessing both first-order kinetic model and the model of simultaneous washing and diffusion, the result indicated that the model of simultaneous washing and diffusion better describes the hydro-distillation mechanism of the essential oil from A. malaccensis leaves. The optimum time, solid to liquid ratio, and the heating power for extracting the highest amount of essential oil were found to be around 3 h, 1:10 (g·ml− 1), and 300 W respectively. Yellow essential oil with a strong smell and a yield of 0.05 v/w was extracted by hydro-distillation Clevenger apparatus. Chemical compounds of the essential oil were analyzed using gas chromatography–mass spectroscopy (GC/MS), which resulted in identification of 42 compounds that constitute 93% of essential oil. Among the identified components, Pentadecanal (32.082%), 9-Octadecenal, (Z) (15.894%), and Tetradecanal (6.927%) were the major compounds. Considering the fact that all the identified major components possess pesticidal properties, A. malaccensis leaves can be regarded as a promising natural source for producing pesticides.

Herb is a famously used as medicinal plant as an alternative to chemicals based medicine since it is safer. Gynura Procumbens (sambung nyawa) is bicolor (green and red) herbal plant which is widely grown in Asia. Recent studies proved that this plant has anti-herpes simplex virus, anti-flammatory and antihyperglycaemic properties. This work investigated the extraction of chlorophyll a and b from gynura procumbens of green-leaf species. Optimization was done both by experiment and also Response Surface Method. Solid liquid extraction was used to extract the chlorophyll a and b. The solid to solvent ratio, temperature, solvent used and extraction time were varied to determine the optimum conditions for extraction. It was found that at 80C in 90 minutes with 2:5 solid to solvent ratio were the most favorable conditions to extract chlorophyll a and b. Five valuable compounds was found from GC-MS analysis which are 2-Hexanal, Phenol, Oleic Acid, Copaene and Phytol. This implies that Gynura Procumbens promises a good source of many useful bioactive compounds.

The current research mainly focuses on transforming low-quality waste into value-added nanomaterials and investigating various ways of utilising them. The hydrothermal preparation of highly fluorescent N-doped carbon dots (N&ndash, CDs) was obtained from the carboxymethylcellulose (CMC) of oil palm empty fruit bunches and linear-structured polyethyleneimines (LPEI). Transmission electron microscopy (TEM) analysis showed that the obtained N&ndash, CDs had an average size of 3.4 nm. The N&ndash, CDs were monodispersed in aqueous solution and were strongly fluorescent under the irradiation of ultra-violet light. A detailed description of the morphology and shape was established using Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). It was shown that LPEI were successfully tuned the fluorescence (PL) properties of CDs in both the intrinsic and surface electronic structures, and enhanced the quantum yield (QY) up to 44%. The obtained N&ndash, CDs exhibited remarkable PL stability, long lifetime and pH-dependence behaviour, with the excitation/emission maxima of 350/465.5 nm. Impressively, PL enhancement and blue-shifted emission could be seen with the dilution of the original N&ndash, CDs solution. The obtained N&ndash, CDs were further applied as fluorescent probe for the identification of Cu2+ in aqueous media. The mechanism could be attributed to the particularly high thermodynamic affinity of Cu2+ for the N-chelate groups over the surface of N&ndash, CDs and the fast metal-to-ligand binding kinetics. The linear relationship between the relative quenching rate and the concentration of Cu2+ were applied between 1&ndash, 30 &micro, M, with a detection limit of 0.93 &micro, M. The fluorescent probe was successfully applied for the detection of Cu2+ in real water. Moreover, a solid-state film of N&ndash, CDs was prepared in the presence of poly (vinyl alcohol) (PVA) polymer and found to be stable even after 72-h of continuous irradiation to UV-lamp. In contrast to the aqueous N&ndash, CDs, the composite film showed only an excitation independent property, with enhanced PL QY of around 47%. Due to the strong and stable emission nature of N&ndash, CDs in both aqueous and solid conditions, the obtained N&ndash, CDs are ideal for reducing the overall preparation costs and applying them for various biological and environmental applications in the future.

Nowadays, to ensure sustainability of smart materials, it is imperative to eliminate or reduce carbon footprint related to nano material production. The concept of design of experiment to provide an optimal synthesis process, with a desired yield, is indispensable. It is the researcher&rsquo, s goal to get optimum value for experiments that requires multiple runs and multiple inputs. Herein, is a reliable approach of utilizing design of experiment (DOE) for response surface methodology (RSM). Thus, to optimize a facile and effective synthesis process for fluorescent carbon dots (CDs) derived from tapioca that is in line with green chemistry principles for sustainable synthesis. The predictions for fluorescent CDs synthesis from RSM were in excellent agreement with the artificial neural network (ANN) model prediction by the Levenberg&ndash, Marquardt back propagation (LMBP) algorithm. Considering R2, root mean square error (RMSE) and mean absolute error (MAE) have all revealed a positive hidden layer size. The best hidden layer of neurons were discovered at point 4-8, to confirm the validity of carbon dots, characterization of surface morphology and particles sizes of CDs were conducted with favorable confirmations of the unique characteristics and attributes of synthesized CDs by hydrothermal route.

Plant oils and their derivatives have been vigorously exploited as alternatives for synthesis of epoxides due to depletion of petroleum resources. In this study, crude jatropha oil (CJO) was subjected to a transesterification process to form jatropha methyl esters (JME) using peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid via an acidic ion exchange resin (AIER). The effect of temperature, molar ratio of hydrogen peroxide to unsaturation, molar ratio of acetic acid to unsaturation, and catalyst loading were investigated. This study revealed that the maximum 89.9% relative conversion to oxirane rings was achieved after 6 h with the optimal reaction conditions of temperature at 70 ˚C, the molar ratio of hydrogen peroxide to unsaturation of 1.5 mol, the molar ratio of acetic acid to unsaturation of 0.5 mol, and catalyst loading of 16%. Fourier Transform Infrared (FTIR) spectra of the epoxidized jatropha methyl esters (EJME) showed oxirane peaks (doublet) at 825 and 843 cm-1.1H NMR confirmed the diepoxide group at 2.85 ppm and 2.98 ppm, while the diepoxide signals of 1C NMR were present at 56.88-57.06 ppm. Production of bio-epoxides from Jatropha methyl esters hence looks promising with favorable physicochemical properties, availability, and versatility.

This study aims at reviewing the alternative techniques for bioethanol recovery, highlighting its advantages and disadvantages, and to investigate the technical challenges facing these alternatives to be widely used. The findings showed that the integration of these techniques with the fermentation process did not meet a large acceptance in the industrial sector. The majority of conducted studies were mainly focusing on ethanol recovery from aqueous standard solution rather than the investigation of these techniques performance in fermentation-separation coupled system. In this context, pervaporation has received more attention as a promising alternative to distillation. However, some challenges are facing the integration of these techniques in the industrial scale as the fouling problem in pervaporation, the toxicity of solvent in liquid extraction, energy consumption in vacuum fermentation. It was also found that there is a lack of the technical economic analysis for these techniques which may limit the spread of its application in the large scale. Currently, hybrid systems integrating distillation with other alternative techniques are considered as an innovative solution to reduce the high cost of the distillation process and the low separation efficiency of the alternatives techniques.

This paper describes the development of an integrated system using a dry film resistant (DFR) microfluidic channel consisting of pulsed field dielectrophoretic field-flow-fractionation (DEP-FFF) separation and optical detection. The prototype chip employs the pulse DEP-FFF concept to separate the cells (Escherichia coli and Saccharomyces cerevisiae) from a continuous flow, and the rate of release of the cells was measured. The separation experiments were conducted by changing the pulsing time over a pulsing time range of 2&ndash, 24 s and a flow rate range of 1.2&ndash, 9.6 &mu, L min &minus, 1 . The frequency and voltage were set to a constant value of 1 M Hz and 14 V pk-pk, respectively. After cell sorting, the particles pass the optical fibre, and the incident light is scattered (or absorbed), thus, reducing the intensity of the transmitted light. The change in light level is measured by a spectrophotometer and recorded as an absorbance spectrum. The results revealed that, generally, the flow rate and pulsing time influenced the separation of E. coli and S. cerevisiae. It was found that E. coli had the highest rate of release, followed by S. cerevisiae. In this investigation, the developed integrated chip-in-a lab has enabled two microorganisms of different cell dielectric properties and particle size to be separated and subsequently detected using unique optical properties. Optimum separation between these two microorganisms could be obtained using a longer pulsing time of 12 s and a faster flow rate of 9.6 &mu, 1 at a constant frequency, voltage, and a low conductivity.

This paper describes the development of a lab-on-chip (LOC) device that can perform reliable online detection in continuous-flow systems for microorganisms. The objective of this work was to examine the performance of a fibre optic detection system integrated into a LOC device. The microfluidic system was fabricated using dry film resist (DFR), integrated with multimode fibre pigtails in the LOC. Subsequently, the performance of the fibre optic detection was evaluated by its absorbance spectra, detection limit, repeatability and reproducibility, and response time. The analysis was carried out using a constant flow rate for three different types of microorganisms which are Escherichia coli, Saccharomyces cerevisiae, and Aeromonas hydrophila. Under the experimental conditions used in this study, the detection limit of 1.0×105 cells/mL for both A. hydrophila and E. coli, while a detection limit of 1.0×106 cells/mL for S. cerevisiae cells were measured. The results also revealed that the device showed good repeatability with standard deviations less than 0.2 for A. hydrophila and E. coli, while standard deviations for S. cerevisiae were larger than 1.0. The response times for A. hydrophila, E. coli, and S. cerevisiae were 104 s, 122 s, and 78 s, respectively, although significant errors were recorded for all three species for reproducibility experiment. It was found that the device showed generally good sensitivity, with the highest sensitivity towards S. cerevisiae. These findings suggest that an integrated LOC device, with embedded multimode fibre pigtails, can be a reliable instrument for microorganism detection.

This paper describes the development of an integrated system using a dry film resistant (DFR) microfluidic channel consisting of pulsed field dielectrophoretic field-flow-fractionation (DEP-FFF) separation and optical detection. The prototype chip employs the pulse DEP-FFF concept to separate the cells (Escherichia coli and Saccharomyces cerevisiae) from a continuous flow, and the rate of release of the cells was measured. The separation experiments were conducted by changing the pulsing time over a pulsing time range of 2–24 s and a flow rate range of 1.2–9.6 μL min−1. The frequency and voltage were set to a constant value of 1MHz and 14Vpk-pk, respectively. After cell sorting, the particles pass the optical fibre, and the incident light is scattered (or absorbed), thus, reducing the intensity of the transmitted light. The change in light level is measured by a spectrophotometer and recorded as an absorbance spectrum. The results revealed that, generally, the flow rate and pulsing time influenced the separation of E. coli and S. cerevisiae. It was found that E. coli had the highest rate of release, followed by S. cerevisiae. In this investigation, the developed integrated chip-in-a lab has enabled two microorganisms of different cell dielectric properties and particle size to be separated and subsequently detected using unique optical properties. Optimum separation between these two microorganisms could be obtained using a longer pulsing time of 12 s and a faster flow rate of 9.6 μL min−1 at a constant frequency, voltage, and a low conductivity.

colourants substances in palm oil mill effluent (POME) are carcinogenic, unfortunately, the commonly applied conventional activated sludge system has been unable to remediate these contaminants. The need for more efficient treatment approach is fundamental in order to sanctuary the environment. A novel start-up approach, which involves augmentation of yeast-extract and diary-waste as recipes added into activated sludge to remediate colourants concentration in POME was employed in this study. The decolourization performance obtained was compared with that of the conventional activated sludge operated under the same conditions. The augmented recipes that best sustained the active biomass was identified and then applied in the subsequent studies. Because of this, the acclimation duration drastically shortens to 31 days, as against 87 days of that of the conventional method. The swift acclimation was due to the adequacy and stability of the sludge active sites, which was successfully increased by 35.31% using the augmented recipe. The decolourization efficiency at steady aeration of 5 L/min and OLR of 0.895gCOD L−1d−1 using augmented sludge was 63.45%, which was far greater than 37% obtained by the conventional sludge. Monod Kinetic model excellently described the degradation process of both augmented and conventional sludge based on COD depletion with a respective R2 value of 0.9923 and 0.9839. The calculated kinetic coefficients proved that microbial growth-substrate utilization rate of the augmented sludge was superior with biomass yield of 2.1142 mg MLVSS/mg COD. The significant improvement in the decolourization was attributed to the augmented recipes, which successfully enhanced the metabolic and xenobiotic activities of the active biomass.

Pentaerythritol tetraoleate esters synthesized from high oleic palm oil methyl ester (POME) have potential as biolubricant base stock. In the present study, the chemical transesterification of POME and pentaerythritol (PE) using sodium methoxide as a catalyst was conducted under vacuum. The effect of operating variables such as reaction temperature, catalyst concentration, the molar ratio of POME to PE, vacuum pressure, and stirring rate on the yield of PE tetraoleate was examined. The ideal conditions for the reaction were at a temperature of 160 °C, 1.25% (w/w) catalyst concentration, the molar ratio of POME to PE at 4.5:1, vacuum pressure at 10 mbar, and stirring speed at 900 rpm. PE tetraoleate with a yield of 36% (w/w), was successfully synthesized under this condition within 2 h of reaction time.

Phenol and formaldehyde are the well-known raw materials used in synthesizing Phenol Formaldehyde (PF) resin. PF resin has been used extensively in various applications including molding and composite laminate industries. This study focused on the synthesizing PF resin using formalin and/or paraformaldehyde for laminate application and assess the physical properties, mechanical properties and fracture toughness of the resins. The density, dynamic viscosity, solid content, gel time, flexural properties, tensile properties and fracture toughness of the synthesized resins were evaluated upon varying the formalin content from 0% to 40% (w/w) in the synthesis process. The result shows that addition of 40% w/w formalin in the PF resin synthesis had increased the fracture toughness and decreased the flexural strength and modulus properties of PF by 97.14% and 97.60% respectively. The tensile stress value was also reduced by 67.80% when the 40% w/w of formalin was added. However, the PF resins that produced by adding formalin up to 20% w/w in the PF resin synthesis, still maintained their flexural and tensile properties within the acceptable range required by EN438 standard for decorative high-pressure laminate (HPL) application. This work shows that paraformaldehyde enhanced the mechanical properties of PF laminate resin compared to formalin.

More recent attention has been focused on the utilization of Jatropha curcas in the field of water treatment. The potential of Jatropha oil in the synthesis of membrane for water filtration had been explored, its performance compared to the addition of graphene oxide (GO) in the polymer matrix. Jatropha oil was modified in a two-step method to produce Jatropha oil-based polyol (JOL) and was blended with hexamethylene diisocyanate (HDI) to produce Jatropha polyurethane membrane (JPU). JPU was synthesized in different conditions to obtain the optimized membrane and was blended with different GO loading to form Jatropha/graphene oxide composite membrane (JPU/GO) for performance improvement. The synthesized pristine JPU and JPU/GO were evaluated and the materials were analyzed using fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle, water flux, and field emission scanning electron microscopy (FESEM). Results showed that the ratio of HDI to JOL for optimized JPU was obtained at 5:5 (v/v) with the cross-linking temperature at 90&deg, C and curing temperature at 150&deg, C. As GO was added into JPU, several changes were observed. The glass transition temperature (Tg) and onset temperature (To) increased from 58&deg, C to 69&deg, C and from 170&deg, C to 202&deg, C, respectively. The contact angle, however, decreased from 88.8&deg, to 52.1&deg, while the water flux improved from 223.33 L/m2.h to 523.33 L/m2.h, and the pore distribution in JPU/GO became more orderly. Filtration of copper ions using the synthesized membrane was performed to give rejection percentages between 33.51% and 71.60%. The results indicated that GO had a significant impact on JPU. Taken together, these results have suggested that JPU/GO has the potential for use in water filtration.

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...