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Photo-driven chemical transformation, also known as photocatalysis, has emerged as a sustainable technology in solving various issues from environmental pollution to energy security. It is straightforward that the success of a photocatalytic process is highly dependent on the type of photocatalyst system being utilized. Graphene, the wonder material, in particular, has emerged as compelling semiconductor support because of its superlative properties such as large specific area, excellent electronic conductivity, high transparency, and good flexibility. Despite the affluent number of studies on graphene-based photocatalysts, there is a paucity of reviews discussing the relationship between the graphite exfoliation routes and the associated properties of graphene nanomaterials which can impart a non-negligible influence on photocatalytic performance. Here, the impact of graphite exfoliation routes on the resultant graphene properties as photocatalyst support is reviewed. The most common top-down graphite exfoliation methods are reviewed, including chemical, liquid-phase, mechanical, and electrochemical exfoliations. The advantages and weaknesses of each exfoliation approach are systematically reviewed while considering the concomitant structural properties and photocatalytic characteristics of the produced graphene. A comparative assessment of different graphene exfoliation routes and their implications on photocatalytic performance is revealed. Recent progress on the applications of exfoliated graphene for various photocatalytic processes, including environmental remediation, water splitting, and CO2 photoreduction to solar fuels, are discussed in-depth.

In the present work, the potential of novel cultivar of safflower seed crop with highest 52% oil contents is evaluated for the first time as a feedstock for biodiesel synthesis. The specific aim of this study was to optimize the transesterification process for maximum biodiesel yield using different parameters and to evaluate its fuel compatibility with mineral diesel. Fatty acid methyl esters (FAMEs) of safflower oil were produced by standard transesterification process using potassium hydroxide (KOH) as catalyst. Optimum biodiesel yield of 98% achieved at 65°C, 5:1 methanol: oil molar ratio, 0.32 g catalyst concentration, and reaction time of 80 min. The kinematic viscosity@ 40°C (cSt), flash point, sulfur contents (wt%), pour point and cloud point of pure safflower oil biodiesel (SOB) were found to be 5.32 mm2/s, 80°C, 0.00041%, –9°C and –11°C, respectively. These together with other fuel parameters were in accordance with ASTM standards. The results obtained indicate that SOB appears to be the potenti...

In this study, oil palm empty fruit bunch (EFB) and kenaf core fibers were converted into sugar for bioethanol production. Results of enzymatic hydrolysis showed that the untreated EFB and kenaf core fibers were hardly to be hydrolysed, in which yielded only 2.6% and 0.4% of reducing sugar (glucose), respectively. In consideration to environmentally friendliness, simple aqueous pre-treatments were carried out prior to hydrolysis aimed to increase sugar production. Based on the results obtained, it was interesting to note that by adopting merely water, acid and alkaline pre-treatments, the total glucose yields were increased to 34.9%, 34.2% and 27.9% for EFB fiber, while 19.3%, 11.7%, and 12.6% for kenaf core fiber, respectively. The results of chemical composition analysis of pre-treated fibers indicated the increase of the sugar production was highly related to the removal of hemicellulose and/or lignin in the fibers. Between the two fibers, pre-treated EFB fiber attained the highest total glucose yield in all the pre-treatments. This revealed that EFB fiber was more viable for sugar production than kenaf core fiber.

This paper reports a study on the performance assessment of di-functional magnetic Fe–Ca oxide catalyst in biodiesel production using hemp oil. In situ co-precipitation procedure was used for synthesis of di-functional magnetic solid base catalyst. The resultant catalyst had good magnetic property with relatively high saturation magnetism (45.6 emu/g) and the reused catalyst status is quite functional. The catalyst was characterized using various techniques including XRD, TG–DTA, SEM and VSM. The produced biodiesel was characterized and conformed by GC/MS, NMR and FT/IR. The synthesis of biodiesel was carried out at constant temperature (60 °C), reaction time (2 h) oil alcohol molar ratio (1:6), agitation (600 rpm) and catalyst concentration (2.25%) w/w. The maximum biodiesel yield was achieved 92.16% using di-functional magnetic Fe–Ca oxide catalyst.

In this study, biodiesel is prepared from Sinapis alba L. oil commonly known as white mustard through transesterification of the crude oil with methanol in the presence of NaOH as catalyst. Optimum conditions for the reaction were established to achieve maximum biodiesel yield of 92% at 6:1 molar ratio (methanol to oil), by using 0.5 g of NaOH, reaction temperature 65°C, and reaction time 75 minutes. Sinapis alba oil biodiesel (SAOB) was testified by using various fuel properties such as kinematic viscosity at 40°C (5.45 cSt), density at 15°C (0.8721 kg/L), acid number (0.242 mg KOH/gm), flash point (90°C), cloud point (−10°C), pour point (−13°C), and sulfur contents (0.00432%). Based on these findings, it is stated that SAOB can be used as alternative fuel in diesel engines.

Calcination of CaCO 3 is a process of producing CaO – a widely used substance in high temperature applications. However, the efficiency of the process depends on the variable involved and the assumption made. Therefore, this paper aims to illustrate the effects of few variables on calcination and carbonation reaction of CaCO 3 via thermo-gravimetric analyzer (TGA) in order to optimize the process. In the present work, cockle shells were used as CaCO 3 sources. The experimental variables i.e. particle size, heating rate, calcination and carbonation temperature were employed. A minimum of two runs of experiments for each variable were conducted and the standard deviation for all of the runs are found to be less than 1. Analysis of XRD, XRF and EDX indicates the conversion of CaCO 3 in cockle shells to CaO after calcination. The optimum adsorptive capacity of synthesized CaO for CO 2 at the optimum conditions is 0.72 kg CO 2 /kg CaO.

Vegetable oil extraction processes are found to be energy intensive. Thermodynamically, any energy intensive process is considered to degrade the most useful part of energy that is available to produce work. This study uses literature values to compare the efficiencies and degradation of the useful energy within Jatropha curcas oil during oil extraction taking into account solvent and mechanical extraction methods. According to this study, J. curcas seeds on processing into J. curcas oil is upgraded with mechanical extraction but degraded with solvent extraction processes. For mechanical extraction, the total internal exergy destroyed is 3006 MJ which is about six times less than that for solvent extraction (18,072 MJ) for 1 ton J. curcas oil produced. The pretreatment processes of the J. curcas seeds recorded a total internal exergy destructions of 5768 MJ accounting for 24% of the total internal exergy destroyed for solvent extraction processes and 66% for mechanical extraction. The exergetic efficiencies recorded are 79.35% and 95.93% for solvent and mechanical extraction processes of J. curcas oil respectively. Hence, mechanical oil extraction processes are exergetically efficient than solvent extraction processes. Possible improvement methods are also elaborated in this study. (C) 2011 Elsevier Ltd. All rights reserved.

A kinetic model for flue gas desulphurization (FGD) using siliceous sorbent was carried out using various different potential/exponential expressions for the rate equation and structural/volumetric expressions for the solid phase equation. The kinetic parameters of the mathematical model were obtained from a series of desulphurization experimental reactions conducted under isothermal conditions at various operating parameters. MATLAB software was utilized to solve the partial differential equations using the finite difference method. It was found that the rate limiting step is a combination of reaction and ash diffusion, in which the former dominates initially and the latter dominates at the later reaction stage. Pre-exponential factor of rate constant, ko, and activation energy, Ea, have been determined as 0.15 s?1 and 15,052 J/mol?1, respectively. As a result, a modified shrinking core model with reaction control coupled with exponential expression of the rate equation was found to best describe the experimental data with an error of 4.8%.

Energy supply and its security issues have been the topic of interest lately. With growing environmental awareness about the negative implications brought by excessive usage of fossil fuels, the race for finding alternative energy as their substitutions is getting heated up. For now, renewable energy from biodiesel has been touted as one of the most promising substitutions for petroleum-derived diesel. Combustion of biodiesel as fuel is more environment-friendly while retaining most of the positive engine properties of petroleum-derived diesel. Production of biodiesel is also a proven technology with established commercialization activities. The huge potential of biodiesel coupled with the abundance of palm oil which is one of the most cost-effective feedstocks for biodiesel is responsible for the pledging of Malaysia to become the leading producer of high quality biodiesel in the region. Currently, total approved installed capacity of biodiesel production in Malaysia equals to almost 92% of the world biodiesel production output in 2008. While Malaysia does indeed possessed materials, technologies and marketing superiority to vie for that position, many more challenges are still awaiting. The price restriction, provisions controversy, escalating non-tariff trade barriers and negligible public support need to be addressed appropriately. In this review, Malaysia's previous and current position in global biodiesel market, its future potential towards the prominent leading biodiesel status and major disrupting obstacles are being discussed. The feasibility of utilizing algae as the up-and-coming biodiesel feedstock in Malaysia is also under scrutiny. Lastly, several recommendations on the roles played by three major forces in Malaysia's biodiesel industry are presented to tackle the shortcomings in achieving the coveted status by Malaysia. It is hope that Malaysia's progress in biodiesel industry will not only benefit itself but rather as the role model to catalyst the development of global biofuels industry as a whole.

The activity of rice husk ash (RHA)/CaO-based sorbent supported with various metal oxides for the removal of SO2 and NO from simulated flue gas of combustion process has been studied. In this study, RHA/CaO-based sorbents were impregnated with an appropriate metal nitrates solution followed by drying and calcinations, which resulted in the sorbent having the following active phases; MgO, MnO, CoO, ZnO, Al2O3, Fe2O3, and CeO2. The sorbent-catalysts were tested in a fixed bed reactor by passing mixture gas consisting of SO2 (2000 ppm), NO (500 ppm), O2 (10 %), water vapor (50%) and N2 as a balance at a total flow rate of 150 mL/min and reaction temperature of 87C. The results showed that RHA/CaO sorbents impregnated with CeO2 displayed the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO2 and NO. Infrared spectroscopic results indicate the formation of both sulfate (SO42-) and nitrate (NO3-) species due to a catalytic role played by CeO2.

Combined photolysis and predominantly photocatalytic degradation of phenol under UV-C light (λ = 254 nm) with the maximum intensity of 5400 μW/cm2 was carried out in a batch reactor. The TiO2 photocatalysts were supported on glass beads, silica gel, and quartz sand using a sol−gel method. The supported TiO2 catalysts were characterized by XRD, SEM, and EDX analyses. Factors affecting the photocatalytic degradation of phenol such as pH, oxygen supply rate, initial phenol concentration, and H2O2 concentration were investigated. TiO2 supported on quartz sand gave the highest efficiency with 90% degradation of 50 mg/L phenol solution in 6 h, followed by TiO2 supported on silica gel and glass beads with 86% and 74%, respectively. The higher photoactivity of supported TiO2 on quartz sand was ascribed to the high crystallinity and high quantity of Ti, and the absence of ions which could inhibit the crystallization on the catalyst surface. The supported TiO2 was found to be stable for repeated use. The results su...

The present work examines the production of biodiesel from distaff thistle (Carthamus lanatus L.) using alkali catalyzed transesterification. The low acid value (0.14 mg KOH/g) and free fatty acid (FFA) contents (2.81%) of distaff thistle oil (DTO) determined prior to transesterification indicated that the pretreatment of raw oil with acid is not required for biodiesel synthesis. The optimum operating reaction conditions of methanol to oil molar ratio (5: 1), catalyst concentration (0.64%) and temperature (60 degrees C) were applied during the transesterification to obtain the highest biodiesel yield of 97%. We have determined various fuel properties of distaff thistle oil biodiesel (DTOB) including kinematic viscosity (5.85@ 40 degrees C c St), acid value (0.14 mg KOH/g), density (0.8980@ 40 degrees C Kg/L), cetane number (50), flash point (126 degrees C), cloud point (10 degrees C), pour point (15 degrees C) and distillation characteristics (358 @ 90% recovery degrees C). The values of fuel properties were found to be comparable with mineral diesel and in agreements with ASTM biodiesel standards. In addition to this, the synthesized fatty acid methyl esters (FAMEs) were confirmed and characterized by Gas chromatography-Mass spectroscopy (GC-MS), Fourier transform-Infra red (FT-IR), H-1 NMR (Nuclear magnetic resonance) and C-13 NMR analyses. Our results conclude that DTO appears to be an acceptable new non-edible oil feedstock for biodiesel industry.

Introduction. Edible wild plants are nature's gift to mankind. Considering the growing need to identify alternative bio-nutritional sources, some underutilized species of figs (Ficus carica L., F. palmata Forssk., F. racemosa L.) and mulberries (Morus alba L., M. nigra L, M. laevigata Wall.) of the family Moraceae were evaluated as wild edible fruits to study their nutritive and mineral composition in order to prioritize their edibility for indigenous people. Materials and methods. The major proximal components (moisture, ash, lipids, proteins, fibers and carbohydrates) were determined by standard AOAC methods. The concentration of various minerals (K, Ca, Mg and Na) and trace elements (Fe, Mn, Zn, Cu and Ni) were recorded by using an atomic absorption spectrophotometer. Results. Our results indicated a range of moisture contents from 17.82-80.37 g center dot 100 g(-1) (fresh weight basis) in F. carica-M. laviegata; protein, 6.31-13.50 g center dot 100 g(-1) (dry weight basis) in F. glomerata-M. alba; crude fats, 1.02-2.71 g center dot 100 g(-1) in F. palmate-F. glomerata; carbohydrates 69.47-75.58 g center dot 100 g(-1) in M. alba-M. nigra; and fiber 7.63-17.81 g center dot 100 g(-1) in M. laviegata-F. palmate, respectively. The significantly highest energy value was computed in M. laviegata (367.7 kcal center dot 100 g(-1)). Moreover, sufficient quantities of essential elements were found in all the studied materials. The highest levels of N [(0.24 +/- 0.07) mg center dot g-1] and Fe [(1.43 +/- 0.42 mg center dot g(-1)] were found in M. laviegata; Na [(1.92 +/- 0.11 mg center dot g-1] and Mg [(6.92 +/- 0.37 mg center dot g-1] in F. palmate; and K [(17.21 +/- 0.03 mg center dot g-1] in F. glomerata. Significant variation existed among the selected species in all the nutritional parameters. Conclusion. According to our results, fig and mulberry fruits are recommended for commercial-scale production for the green industry to overcome food crises as they are potential food sources, particularly Morus laviegata and Ficus palmata, with rich nutritional attributes and mineral profiles.