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The present study investigated biodiesel production from the transesterification of palm oil with methanol using calcined biomass durian peel (BDP) as a heterogeneous catalyst assisted by microwave irradiation. Characterization of the calcined BDP showed that K2O is the main compound with a concentration of 86.15 wt%. The effect of three independent variables of catalyst weight (3–12 wt%), reaction time (1–10 min), and power of microwave (180–900 W) was used to determine the optimum condition on biodiesel production using the response surface method-based on the Box–Behnken design experiment. The optimum biodiesel conversion of 97.3% was achieved under experimental parameters of catalyst concentration of 12 wt%, reaction time of 9 min, and microwave power of 180 W. The catalyst concentration and reaction time have significant effects on biodiesel conversion.

The continuous use of fuel reduces oil reserves which causes the availability of petroleum in Indonesia tend to decrease. To overcome the problem of oil supplies, renewable energy is needed as an alternative fuel, one of which is bio-gasoline as a substitute for gasoline. Bio-gasoline can be made from Crude Palm Oil offgrade via catalytic cracking that has the advantage of simple tools and shorter processes cracking. Heterogeneous catalyst CaO/α-Fe2O3 made of alkaline calcium oxide which can reduce the acidity of biogasoline and α-Fe2O3 nanoparticles acidic which can trigger the breakdown of the hydrocarbon chain. This study aims to synthesize bio-gasoline from CPO offgrade through catalytic cracking reactions using CaO/α-Fe2O3 heterogeneous catalyst. The results showed that bio-gasoline has been successfully produced by the cracking method with a yield of 46.18%. Based on GC-MS analysis of the product it is suspected to contain mixed compounds from the biogasoline such as heptane, octane, decane, nonane, and undecane. Physico-chemical characteristics of the biogasoline product for fraction III (F3) include density, viscosity, acid number, iodine number, and refractive index respectively of 0.73 g/mL; 2.76 cSt; 15.639 mg KOH/g sample; 2.29 g Iod/100g sample; and 1.465. The Biogasoline characterization is close to the Gasoline quality standard No. 0177.K/10/DJM.T/2018.

Silica is the most abundant compound on the Earth’s surface. The content of silica can be found in agricultural waste ash and mineral rocks. Extracting silica from natural sources is advantageous due to its economic feasibility and easily obtained. Silica has a wide range of applications, such as in fertilizers, adsorbents, organic reaction catalysis, biofuels/alternative energy production, and as an antimicrobial agent. One type of rock that contains the highest amount of silica is Pyrophyllite. Recent research trends have focused on various methods and sources for silica extraction, yet extracting silica from mineral rocks presents its own challenges. Pyrophyllite rock contains a high amount of silica, but its extraction is quite difficult due to the presence of crystalline silicate mineral phases. This study aims to compare the silica extraction process on Pyrophyllite rocks from Malang using the sol-gel method versus the alkali fusion method.

Waste cooking oil is a potential raw material for biodiesel. The use of heterogeneous catalysts and ultrasonicator will optimize the transesterification and environmentally friendly. The transesterification study with SrO-KF nano catalyst has been carried out. The objectives of this study are: (1) to determine the optimum conditions for SrOKF catalyst in the synthesis of biodiesel of the refined waste cooking oil and (2) to compare the results of the methyl ester with biodiesel standards. The steps of this study were: refinement of waste cooking oil, synthesis of SrO-KF nano-catalyst, and the transesterification. The catalyst applied ratio of 1:1, 1:2, and 1:3 of SrO:KF with concentrations of 2%, 3% and 4% by weight of oil respectively. The results of heterogeneous catalyst using XRD and SEM showed that SrF2, SrO and KF compounds had been formed. The optimum transesterification conditions were obtained on SrO-KF catalyst (1:2), concentration of 4% (w/w) with a yield of 85.12% (w/w). The methyl ester of waste cooking oil has density of 884 kg/m³, acid number of 0.48 mg/g, and viscosity of 4.2 cSt. Methyl esters of waste cooking oil were composed of 25.14% methyl palmitate and 33.65% methyl elaidate, 11.27% methyl linoleate, 10.14% methyl lauric and other methyl esters. [ABSTRACT FROM AUTHOR]

The Fischer-Tropsch synthesis converted hydrogen and carbon monoxide into linear hydrocarbons as liquid fuel. Iron and cobalt were used as polymerization catalyst, that impregnated on HZSM-5. The Fe-Co/HZSM-5 could be applied as bifunction catalyst which combined polymerizing synthesis gas and long chain hydrocarbon cracking for making biofuel. The objective of this study is observing the effect of temperature and composition of iron and cobalt combination, supported by HSZM-5 (Fe-Co/HZSM-5) catalyst on fuel product composition. The results obtained from this study would be used to find optimum condition for various iron and cobalt ratio in the catalyst. The mesoHZSM-5 was prepared from ammonium ZSM-5 over calcination, desilication, and dispersion. The mixed solution consisted of Co(NO3)2.6H2O and Fe(NO3)3.9H2O were used as precursor for incipient wetness impregnation on HZSM-5. The catalyst performance was observed in a continuous fixed bed reactor using Fe-Co/meso-HZSM-5 catalyst with synthesis gas at various composition iron and cobalt ratio (10-40 % wt. Fe in Co), various temperature (225-275 °C) at 20 bars. All catalysts were reduced in situ in the reactor. The 10Fe-90Co/mesoHZSM-5 catalyst was more suitable for FTS at 250 °C with alkane (20.49 %) as the main product and alcohol as the by-product (79.51 %). The others catalysts composition of 20-40 % Fe (by weight) in Fe-Co were more suitable for FTS at 225-250°C because under these conditions, alkanes as the main product were obtained in relatively higher compositions compared to other compounds. The mechanism of paraffins, olefins, aldehydes and alcohols formation in this FTS reaction followed the hydrogen assisted CO dissociation with CO-insertion mechanism. [ABSTRACT FROM AUTHOR]

This article explores the degradation of glycerol to ethanol using different catalysts and the effect of sonication time on the reaction. The study found that the NiMo/YZ catalyst was the most effective in producing ethanol, and the longer the sonication time, the higher the yield of ethanol. The Y Zeolite was activated and impregnated with Ni and Mo metals to act as active catalyst sites. The article also mentions the potential for further research on metal leaching and the by-products of glycerol degradation. [Extracted from the article]

One of the aquaculture wastes is shrimp pond wastewater (SPW). Generally, SPW comes from the rest of shrimp feed, shrimp dung, and died shrimp during the cultivation. As SPW is organic waste, biological wastewater treatment is the best choice. Biological method has low operating costs and environmentally friendly. There are two kind of biological methods, namely aerobic and anaerobic. Both methods have advantages and disadvantages. In this research, the performance of aerobic and anaerobic methods in treating SPW were investigated using batch experiment during start-up for 105 days. The results showed that the performance of the aerobic system in the initial phase was better than that of the anaerobic system, especially, in phase one which is the adaptation phase. At the beginning of the experiment, the performance of aerobic system is better than that of the anaerobic system. The COD, carbohydrate and protein removals in the aerobic system were 25.93%, 75.20% and 88.59%, while in the anaerobic system were 12.82%, 36.03% and 51.01%. Overall, based on the COD removal, the performances of start-up process of both systems were quite similar. Therefore, it needs more study to investigate the aerobic and anaerobic systems for a longer duration in a continuous or semi-continuous system. [ABSTRACT FROM AUTHOR]

In this work, the Fe3O4 nanoparticles from natural iron sand were doped with Mn and combined with reduced-graphene oxide (rGO) to obtain MnxFe3-xO4/rGO nanocomposites with mole fraction variations of the Mn of 0.25, 0.5, and 0.75. The crystalline phase of the synthesized MnxFe3-xO4/rGO nanocomposites formed an amorphous phase. The presence of rGO was observed through EDX results. The magnetical properties of MnxFe3-xO4/rGO nanocomposites were shown by decreasing the Br, HcJ, Hmax along with increasing of Mn doping. Interestingly, increasing rGO and Mn composition made the absorption bandwidth of the MnxFe3-xO4/rGO nanocomposites wider, so that the radar absorption also increased marking by the greater reflection loss that reached -11.95 dB. The increase in the radar absorption performance of MnxFe3-xO4/rGO nanocomposites came from the efficient complementarity between dielectric loss and magnetic loss and interfacial polarization between Fe3O4 doped Mn and rGO. [ABSTRACT FROM AUTHOR]

Various solid base catalysts have been used for biodiesel production from different edible and non-edible vegetable oils. Hitherto, reports pertaining to dual-basic metal oxides onto an acidic support is very limited. Herein, we have conducted a novel study using Na2O-K2O and MgO-CaO impregnated into Active Natural Mordenite (ANM) as Na2O-K2O/ANM and MgO-CaO/ANM for kapok seed oil transesterification. The physicochemical properties of the as-synthesized catalysts were analyzed using XRD, XRF-He, SEM, AAS, acidity, and surface area. The results showed that the activation of natural mordenite could reduce impurities, increase acidic strength, and the surface area. A series of ratio on Na2O:K2O and MgO:CaO was fine-tuned to give the highest biodiesel production. The catalyst, Na2O-K2O/ANM, with a concentration of 50% and ratio of 1:1 showed the lowest acidity, 0.352 mmol/g, and gave the highest yield of 72.29%. The highest yield, 84.54%, was obtained from MgO-CaO/ANM (40%; 2:1), with the lowest acidity of 0.331 mmol/g. Biodiesel properties, from the transesterification of the kapok seed oil, were characterized by SNI 7182:2015 standards. The characteristics of synthesized biodiesel met the used standard, and in terms of reaction activity, it is found that the alkalinity level of the catalyst is more influential than its surface area. [ABSTRACT FROM AUTHOR]

Goat milk kefir has high nutritional value, especially in protein and calcium content and has a low lactose content. Vacuum drying is an alternative to remove the water content in kefir so that it can extend the shelf life because it inhibits bacterial growth. This study determines the effect of aging time and drying time using vacuum drying method on the characteristics and amino acid composition of goat milk kefir (kefir and powder kefir). Fermented goat milk (24 hours) use kefir grains without aging and with aging times of 1, 2, 3, 4 (week). The total titrated acid and fat content were significantly different in kefir, but it is not significantly different in powder kefir. The yield, moisture, ash, protein, fiber, and fat in both kefir and powder kefir did not show significant differences. The best treatment based on the exponential comparison method for both powder kefir and kefir was 3 weeks of aging time. Therefore, the amino acid components in powder kefir and kefir underwent changes. The highest total amino acids in kefir was kefir without aging. The highest amino acid of powder kefir was obtained after 2 weeks of aging time. [ABSTRACT FROM AUTHOR]

Off Grade Crude Palm Oil (CPO) is known as renewable waste source. By catalytic cracking of Off Grade CPO, it is potential use for biogasoline. However, the production remains a problem from heterogeneous catalysis. Active site of α-Fe2O3 can be improved with metal impregnation of Cobalt (Co) and Molybdenum (Mo). Therefore, this study were: (1) to synthesize Co-Mo/α-Fe2O3 catalyst assisted by ultrasonic wave, and (2) to synthesize biogasoline from Off Grade CPO by catalytic cracking method using Co-Mo/α-Fe2O3 catalyst with determining the ratio effect of Co:Mo metal impregnation and the effect of its concentration. The steps included: (1) synthesis of hematite (α-Fe2O3) with precipitation method, (2) impregnation of Co-Mo metal on hematite (α-Fe2O3) using the wet impregnation method with the ratio of addition of Co-Mo metal with 1:2; 1:1; 2:1, (3) catalytic cracking of Off Grade CPO using Co-Mo/α-Fe2O3 catalyst with concentration of 0.5%; 1%; and 1.5% w/w, and (4) Characterization and identification of biogasoline components using GC-MS and FTIR. The results showed that Co-Mo/α-Fe2O3 catalyst was successfully synthesized as confirmed by XRD and SEM. The best catalytic cracking of Off Grade CPO was carried out by 0.5% w/w Co-Mo(1:1)/α-Fe2O3 catalyst which produced biogasoline yield of 31.37%. The characteristics of the best synthesized biogasoline included density of 0.77 g/cm3, viscosity of 2.561 cSt, refractive index of 1.454, acid number of 56.793 mg KOH/g, and iodine number of 100.515 g I2/100 g. The main component of biogasoline was undecane compound. [ABSTRACT FROM AUTHOR]

The synthesis of biodiesel via transesterification needs to be improved by the heterogeneous catalysts. So, the study aimed to determine the best conditions for the synthesis of biodiesel produced through a transesterification reaction using waste cooking oil with a Na2O/γ-Al2O3 catalyst assisted by ultrasonic wave. The steps were: catalyst preparation, oil preparation, esterification, transesterification reactions using methanol and various Na2O/γ-Al2O3 catalysts, and characterization. The results showed that the refined waste cooking oil using FTIR was known that there was still a carbonyl group indicating the presence of triglycerides. Free Fatty Acid content of waste cooking oil after esterification was 0.40%, so that the transesterification reaction could be carried out. The XRD results of the catalyst showed a conformity with the reference and it was determined by the Scherrer formula that the crystal size of the catalyst was 30.59 nm. The best condition for biodiesel synthesis was obtained at a catalyst ratio of 1:1 as much as concentration 3% w/w for 15 minutes of ultrasonication, 65 °C, and molar ratio of methanol: oil (12:1), for the yield of 83.51%. After identification through GC-MS, it was known that the main components in the transesterified biodiesel from waste cooking oil were methyl elaidate (38.54%), methyl palmitate (30.90%) and methyl linoleate (16.61%). [ABSTRACT FROM AUTHOR]

Biodiesel products show corrosive properties. Biodiesel contains components of saturated and unsaturated esters which tend to be unstable, sensitive to light, temperature, and metal ions. Thus, the study aims to synthesize biodiesel from various vegetable oils (palm oil, sunflower seed oil, and candlenut oil), and to analyze its corrosiveness to ferrous nails and characterization of biodiesel. The research stages were: synthesis of methyl ester and its characterization, and corrosion test. The results showed that the methyl ester characteristics of the samples meet requirements with SNI7182 : 2015. In GC-MS results, the largest components of methyl esters from candlenut oil and sunflower seed oil were 35.04% methyl oleate and 46.79% methyl oleate respectively, while in palm oil, the largest components were 41.60% methyl oleate and 41.16%. methyl palmitate. Corrosion test showed that the corrosion rate of ferrous nail in biodiesel at room temperature was lower than 70 °. Based on GC-MS and SEM results, biodiesel contained high unsaturated fatty acids and had a corrosion rate, i.e., at room temperature, the methyl ester of palm oil, candlenut oil, and sunflower seed oil were 0.006 mpy, 0.011 mpy, and 0.011 mpy respectively, while at 70 °, they were 0.011 mpy, 0.016 mpy, and 0.017 mpy, respectively. The results corresponded to SEM results at high temperature and significantly high content of unsaturated fatty acids. It was indicated by the formation of pits. [ABSTRACT FROM AUTHOR]

Biodiesel from natural materials has proven its contribution as a renewable energy source. Exploration of natural materials has expanded until many studies have begun to consider natural waste materials to reduce the impact of environmental damage. A natural material that is still considered waste is Low/Off Grade Crude Palm Oil (CPO). Research on this waste has begun to be projected as a raw material for biodiesel. Research on the use of various catalysts in the transesterification and esterification reaction of this waste has expanded. Then, the biodiesel produced has unique characteristics. Thus, some of these studies have been reviewed on a small scale. From that, it is proposed a route to utilize Low/Off Grade CPO which is sustainable and renewable. Therefore, this review article aims to provide a unique understanding of research on the use of Low/Off Grade CPO as biodiesel. [ABSTRACT FROM AUTHOR]