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The purpose of this study was to determine the characteristics and the effectiveness of Cd/ANZ, Cr/ANZ, and Cd-Cr/ANZ catalysts on conversion process of glycerol to ethanol. Zeolite was activated using 1% HF and refluxed with 6 M HCl and 1 M NH4Cl. Catalysts of Cd/ANZ, Cr/ANZ, and Cd-Cr/ANZ are white granules with a size of 100 mesh. The Catalysts were characterized using XRD, XRF, surface area analysis, and catalyst acidity test. Conversion of glycerol to ethanol by ultrasonic assistance was done in various time of 2, 4, and 6 hours. The result of XRF and XRD characterization showed that natural zeolite is mordenite. Specific surface area of catalyst of Natural Zeolite, H-ANZ, Cd/ANZ, Cr/ANZ, and Cd-Cr/ANZ were 140.06, 129.66, 124,534, 126.348, and 135.218 m2/g respectively. The total acidity level of Activated Natural Zeolite, H-ANZ, Cd/ANZ, Cr/ANZ, and Cd-Cr/ANZ catalysts were 0.74, 1.41, 0.49, 0.47, and 0.43 mmol/g respectively. The highest glycerol conversion was obtained when Cd-Cr/ANZ catalyst was used and in a sonication time of 6 hours with yield of 43.84% wt ethanol. [ABSTRACT FROM AUTHOR]

Shrimp farming in Prigi Bay adjacent the seawater produces ammonia organic waste which has the potential to cause marine pollution. To identify and map the ammonia content of shrimp ponds around the sea, we investigated the ammonia content in sludge sediment. Identification of ammonia in sediments were used and applied the Phenate and Nessler methods, respectively and then mapped using Arcgis software. Ammonia contents by Phenate identification was chosen as a method with good linearity (r = 0.999), which is higher than the Nessler method (r = 0.994). The results of accuracy and precision in this method reached ∼100% of recovery and 1.23% of RSD. This method is very suitable for mapping ammonia as a marine pollution. The results of the shrimp pond ammonia levels showed from 2.899 to 23.270 mg/L. The results of the analysis of shrimp pond waste sediment exceeds the quality standard of ammonia which has the potential to pollute the sea. Mapping of the potential for ammonia pollution is clearly divided into several polluted zones, indicating alarm pollution in the seawater. [ABSTRACT FROM AUTHOR]

Biodiesel is classified as a high demand energy in Indonesia, so the production process needs to be optimized to be effective and efficient. Biodiesel production through the transesterification reaction always produces waste as a by-product, such as glycerol, residual fatty acids, residual alcohol, and residual alkaline species. The problem is that the separation of the mixture is still difficult to do. Many studies use traditional methods (such as washing and evaporation) and they cause to be ineffective. Alternatively, research needs to be expanded on the synthesis of materials with special designs for the separation of the mixture resulting from the transesterification reaction. Therefore, we review a unique material design, namely amphiphilic material. By design, this material is made as a heterogeneous inorganic material and it only has two solubility active sites, such as hydrophilic and hydrophobic. This material has been studied about the used method, the success of the synthesis, and its structural properties. Next, we have described the challenges and problems in the synthesis of this material. In addition, we have formulated a catalysis system design for the separation of the transesterified mixture, so that it can estimate the steps of the catalysis process of biodiesel synthesis. [ABSTRACT FROM AUTHOR]

ZSM-5-based catalysis are versatile catalytic systems for a wide range of laboratory studies. The chemical composition, ion exchange, and pore size structure attributes of zeolites are responsible for their extensive catalytic applications. Generally, ZSM-5 catalysis are used with variation of impregnation of transition metal for esterification and transesterification process. Esterification and transesterification are both of the important and routinely processes in diverse fields of organic synthesis. It has a long history in laboratory work due to its versatility for biodiesel production. This review intends to give a detailed insight into the significance of ZSM-5-based catalysis for biodiesel production, such as the used method of its synthesis, the structural characterization with XRD, XRF, and SEM instrument. Then, this article describes about the potential of ZSM-5-based catalysis for biodiesel production with its yield. So, we can get the information of the optimization of ZSM-5-based catalysis that can catalysis in esterification and transesterification process for biodiesel production. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the effectiveness of the conversion of glycerol into ethanol using an Ag-Zn/ZSM-5 catalyst with ultrasonic assistance at a temperature of 60 oC with variations in sonication time of 2 hours, 4 hours, and 6 hours. This research was carried out in 4 stages, namely: (1) activation of ZSM-5 with NH4Cl, (2) Impregnation of Ag metal, Zn metal and a mixture of Logan Ag and Zn metal, (3) Characterization of ZSM-5 catalyst resulting from activation and impregnation, (4) ultrasonic-assisted conversion of glycerol to ethanol with time variations. The characterization of the catalyst used XRF, XRD, acidity and surface area analysis, while the GC tool was used to analyze the results of the conversion of glycerol into ethanol. The results showed that the Zeolite ZSM-5 was successfully impregnated with a mixture of Ag and Zn metals as evidenced by XRD analysis, namely that there was a similarity of peaks at an angle of 2θ with the JCPDS standard and the results of XRF analysis were obtained that impregnated Ag and Zn metals were 13.3 wt% and 10.7 wt%. Optimum degradation time for glycerol conversion glycerol to ethanol using Ag-Zn/ZSM-5 catalyst with ultrasonic assistance at a temperature of 60 oC is 4 hours with a yield of 45 wt%. [ABSTRACT FROM AUTHOR]

The study aimed to know the effect of size of the activated natural zeolite as a catalyst and sonication time on conversion of cellulose to glucose through hydrothermal method. Natural zeolite was crushed and sieved in the size of 50, 100, and 200 mesh. Zeolite was activated by means of heating at a temperature of 500 °C for 5 hours. The zeolite was characterized using XRD and BET. Hydrothermal conversion of cellulose using variation of zeolite size as a catalyst and sonication time. Product of conversions were measured using the Nelson-Somogyi test. The results showed that the type of natural zeolite is a mordenite. Surface area of activated natural zeolite in the size of 50, 100, and 200 mesh is 13.065, 99.096 and 27.081 m2/g respectively. The highest yield of glucose obtained when it was used an activated natural zeolite in the size of 100 mesh and sonicated as long as 240 minutes with the glucose yield of 12.69 wt%. [ABSTRACT FROM AUTHOR]

Petroleum reserves continue to decline, providing challenges and opportunities in the development of renewable energy, for example the use of biodiesel. Tobacco seed oil is known to be used as biodiesel through transesterification reaction with methanol by means of base catalyst such as CaO-KCl. Methyl ester can be used as biodiesel and also has the potential to be used as an antibacterial compound. The objectives of this study were 1) to synthesize methyl ester from tobacco seed oil using catalysts CaO-KCl assisted by ultrasonic, 2) to characterize methyl ester and its potential as a biodiesel, 3) to determine the component compounds of the methyl esters by GC-MS, and 4) to test the bioactivity of antibacterial oil seeds tobacco and methyl esters on the bacterium Escherichia coli. The results of the study showed that 1) synthesized methylester obtained using catalyst of CaO-KCl 3, 4, and 5% w/w oil produced yields of 63.12; 64.78; and 70.29% methylester respectively 2) the character of methylester is qualify in SNI standard of Biodiesel, 3) synthesized methylester that was analized using GC-MS indicate the presence of methyllinoleate 35.64%, methyloleate 20.99%, and methylpalmitate 12.98%, and 4) methylester synthesized with CaO-KCl catalyst had moderate antibacterial bioactivity against Escherichia coli bacteria. [ABSTRACT FROM AUTHOR]

The purpose of this research are to synthesis methyl ester from used cooking oil refined with zeolite and activated pumice and to investigate its potential as biodiesel. The research stages were activating the natural zeolite and pumice with temperature variations of 500 and 600 °C, refining waste cooking oil with various concentrations, trans-esterification of refined waste cooking oil, characterization and identification of methyl esters by using Gas Chromatography-Mass Spectrometry (GC-MS). The best refining was resulted from free fatty acids and clarity at a concentration of 30% natural zeolite with a yield of 67.17%. The trans-esterified methyl esters have a density of 0.881 g/mL, refractive index of 1.447, viscosity of 4.92 cSt, acid number of 0.49 mg-KOH/g, and saponification number of 198.8 mg-KOH/g, which have high potential as biodiesel. The main components of trans esterified methyl ester from refined waste cooking oil are methyl palmitate, methyl oleate, and methyl stearate with the compositions of 46.27, 40.26, and 5.19%, respectively. [ABSTRACT FROM AUTHOR]

We conducted the desalination process of seawater into clean water using silica produced from natural sediment. The sediment contains Si-O-Si and Si-OH groups in the silica to absorb NaCl substances in the seawater. Silica from natural sediment was purified from heavy metals using acid reflux and then measured physical and chemical characterization. The XRF analysis, calcination process, FTIR and AAS analysis were investigated to produce and optimize silica from a sediment sample. The application of silica was applied to absorb NaCl in Prigi Seawater. The results indicated the white silica adsorbent had a typical peak stretching vibration of Si–OH groups visible at wave number 3200-3400 cm−1 as the potential situs of Na+ ion adsorbent. The effective temperature in the produced silica sediment was at 800°C with adsorbed Na+ ion on the artificial seawater of 25 mg/L (16.7%) while the Prigi seawater sample was 60.8 mg/L (10.7%). The produced silica can reduce the salt content of Prigi Seawater. [ABSTRACT FROM AUTHOR]

Organic material pollution is of particular concern in marine sediments other than inorganic material. The organic material that is suspected as a source of pollutants is formaldehyde. We analyzed the ability of the sediment to absorb organic material, especially formaldehyde. In the first stage of research, we conducted the validation of methods to determine accuracy and precision, and then a preliminary test was carried out to determine whether formaldehyde contained in the sediment. We used the bulk grain size, 200 mesh, 400 mesh to absorb the formaldehyde with concentrations of 0.5%; 0.1%; 0.05% and 0.01% to establish a method using GC-MS. Marine sediment with 200 mesh successfully absorbed and reconstructed the formaldehyde pollutant. [ABSTRACT FROM AUTHOR]

Zeolite is a unique mineral because of its easy crystal structure arranged, so that it can be modified according to the needs of the user and can be used for a specific purpose. Zeolite has proven widely used in the adsorption of textile dye waste. Some studies on zeolite modification has been done to increase the adsorption capacity of modified zeolite on dyes, especially toxic dyes. The existence of zeolite in Indonesia is very abundant. However, natural zeolite needs to be purified before being modified. Research in zeolite as an adsorbant is still considered having can be expected to solve the problem of pollution due to dyestuffs, especially textile dye waste. Modifications can be made by adding other adsorbents that are not stable in their application or by adding metals that can increase the Lewis acid properties. This review article aims to describe the research on modification of natural zeolite to be used as an adsorbent for textile dye waste. [ABSTRACT FROM AUTHOR]

Currently, studies on the conversion of waste into valuables such as catalysts are being developed. This effort is in line with the mission of tackling the energy and environmental crises at the same time. The energy crisis is related to the increasing need for renewable energy sources. The environmental crisis is related to the increasing abundance of waste in the environment. For this reason, this study aims to be part of the efforts to overcome the two crises, namely synthesizing CaO/CoFe2O4 catalyst to increase the efficiency of biodiesel production with CaO extracted from chicken eggshells waste. Synthesis the catalyst was conducted by impregnation method of CaO and CoFe2O4. The results of XRD and SEM/EDX analysis showed that CaO/CoFe2O4 was successfully synthesized with a specific surface area of 30.622 m²/g. Based on the results of this research, it can be concluded that CaO/CoFe2O4 produced can be expected to be potential catalyst of biodiesel production. [ABSTRACT FROM AUTHOR]

Silica in Prigi marine sediments can be used as an adsorbent. Previous studies confirm silica inability to absorb Na+ ions optimally. Thus, a study on other adsorbent combinations for the performance of silica in samples on a laboratory scale is required. One of the adsorbent combinations that need to be considered is activated carbon. The combination of activated carbon and silica in the manufacture of membranes is used for seawater filtration and simultaneous adsorption in the seawater desalination process. This study aims to investigate the effect of the addition of activated carbon on the manufacture of silica membrane and its performance in the process of absorbing Na+ ions in Prigi seawater. The sediment content of Prigi Bay, Indonesia, contains silica which has Si-O-Si and Si-OH, so that it is expected that the sediment can absorb Na+ ions. This research determined the sampling point, took and prepared sediment samples, then investigated it using XRF, XRD, and SEM-EDX, sediment ashing, extraction of silica from sediment ash, manufactured of sedimentary silica membrane for Na+ ion analysis, characterized of activated carbon silica membrane by FTIR, as well as membrane applications in the Na+ ion test. [ABSTRACT FROM AUTHOR]

This research was conducted based on the manufacture of chitosan membrane in the process of adding silica to adsorb Na+ ions. The added silica comes from the natural sediments of the Prigi Bay. The content of the sediment is silica, which has Si-O-Si and Si-OH groups so that the sediment is expected to be able to absorb Na+ ions. This study aims to understand the addition of silica in the chitosan membrane in the level of absorption of Na+ ions. Furthermore, modification of the chitosan membrane is carried out to produce a membrane that has better characteristics. For example, it can increase the stability in the membrane, can reduce the pore size so that the separation of a solution by the membrane becomes more effective. The design of this study is to determine the sampling point, take and prepare sediment samples, XRF testing, XRD testing, SEM-EDX testing, sediment ashing, silica extraction from sediment ash, membrane making with the addition of chitosan for Na+ion adsorption, membrane characterization with FTIR, and application membrane in the Na+ ion test. The results obtained from this study are silica from marine sediments, which are white in color which has a characteristic peak of stretching vibration of the -OH group which appears at wavenumber 3200-3400 cm-1, and the addition of silica can increase the performance of the membrane in the absorption rate of Na+ ions. The optimization level of the membrane on the maximum adsorption power of Na+ ions is 96.90 % on a laboratory scale, and Prigi seawater is 84.32%. [ABSTRACT FROM AUTHOR]

Until now there are has not been any concrete utilization of used cooking oil (jelantah). This research seeks to convert this cooking oil waste into biodiesel. According the actual that cooking oil still contains free fatty acids can be converted into methyl esters through transesterification reaction. This effort is in line with the increasing requirement for renewable energy sources. But to achieve maximum reaction results of transesterification without using a catalyst, need supercritical conditions. Even more cooking oil waste is a low quality oil with high levels of free fatty acids and high rancidity. Therefore it is necessary to think about optimum process conditions and needed superior catalysts in the transesterification process. One catalyst that thought to be superior is CaO/CoFe2O4. Eggshell solid waste can be used as a natural source of CaO, through high temperature heating (calcination). The purpose of this study is produces biodiesel from waste cooking oil using CaO/CoFe2O4 from eggshells catalyst. This research objectives were achieved through the following main steps: (1) Synthesis of activation zeolite for rafination process; (2) Pre-treatment of cooking oil waste; (3) Trans-esterification reaction from cooking oil waste using CaO/CoFe2O4 eggshells waste; (4) Optimization of trans-esterification reaction; (5) characterization of methyl esters produced and see their potential as biodiesel. Based on the results of FTIR, yield analysis, GC-MS, the result product is methyl ester and its potency to be biodiesel. The catalyst application in the transesterification reaction made from used cooking oil is expected to provide a conversion is about 80%. [ABSTRACT FROM AUTHOR]

The heterogeneous catalysts in biodiesel synthesis is more environmentally friendly and reusable. Alkaline earth oxides are less alkaline than alkaline oxides. Biodiesel is an alternative fuel, which has been started to be developed as a renewable energy. The aim of this study was to synthesize biodiesel from low-quality crude palm oil (CPO) with heterogeneous catalyst of MgO-K2O using ultrasonic waves. The stages in this study were (a) activation of natural zeolites, (b) refining of low quality of CPO, (c) synthesis of MgO-K2O catalyst at ratio of 10 : 1, 10 : 2, 10 : 3 (MgO : KOH) and (d) transesterification of esterified CPO (variations in the amount of catalyst 10%, 15%, and 20%). This research achieved the optimum conditions for methyl ester synthesis at ratio of 10 : 2 (MgO : KOH) of catalyst composition (15% w/w of oil), and the yield was 88.086%. The character of the methyl ester was in accordance of Indonesian biodiesel standard, therefore, the methyl ester obtained has the potential as biodiesel. The composition of the synthesized methyl ester were 1.96% methyl myristate, 40.42% methyl palmitate, 44.32% methyl oleate, and 7.46% methyl stearate. [ABSTRACT FROM AUTHOR]

The characteristics of yogurt are influenced by the concentration of the starter and incubation time. This study aims to determine the effect of variations in starter concentration and incubation time on the characteristics of yogurt. To achieve this objective, the study was carried out through several stages, namely sample preparation (pasteurization of cow's milk); incubation of cow's milk yogurt with variations in starter concentration and incubation time; characterization of the physical and chemical properties of yogurt. The physical properties were investigated through organoleptic tests of color, aroma, taste, and texture, along with pH and viscosity tests. In contrast, the chemical properties were analyzed from the total acid levels and protein levels. The results show that the variation in the treatment of yogurt production significantly affects the physical and chemical characteristics of the yogurt produced. The produced yogurt's pH is in the range of the standard value set by Food Standards Australia New Zealand (FSANZ). Besides, the amount of produced yogurt's total acid and protein concentration in this study are also met in the standard value set by the Indonesian national standard of yogurt. Moreover, the Mann-Whitney test results show excellent characteristics of yogurt produced. It has a soft texture, a distinctive aroma of yogurt, sour flavor, and white color. [ABSTRACT FROM AUTHOR]

Nowadays gout is still a problem, both nationally and globally. The most widely used commercial drug to treat gout is allopurinol, which act as xanthin oxidase inhibitor, thus inhibiting uric acid synthesis. However, the use of allopurinol in a relatively long time can cause various unwanted side effects. Previous studies have shown that ethanol extract of sugar apple, which is rich flavonoids can inhibit the xanthine oxidase enzyme, but the structure of flavonoid in this fruit is still unknown yet. The aims of this study are to obtain ethanol extracts from the flesh of sugar apple, purify the extract by partitioning techniques using n-hexane and chloroform solvents, test inhibitory activity against xanthine oxidase and identify the flavonoid content using LC-MS/MS analysis. The results have shown that from 800 g the fruit flesh can be obtained 106 g of concentrated ethanol extract. After purification by partitioning using hexane and chloroform purified ethanol extract ed contained flavonoids, with TPC value of 16.11 ± 0.72 (mgGAE/g) and TFC value of 36.79 ± 2.96 (mgQE/g), in the same volume (0.01 mL) has xanthine oxidase inhibitory power by 75.17% compared to 1 mL of allopurinol 100 ppm and one of the dominant flavonoid compound contained was 3',4',7-trimethoxyflavan. [ABSTRACT FROM AUTHOR]

A coral skeleton is one of the biomonitoring agents that is useful to consider the seawater's situation pollutant. It can record contaminants' reconstruction and predict pollution history, especially of Fe3+ and F− ions as the pollutant in the seawater. We investigated Fe in the coral skeleton and added F− ions in seawater as the reconstruction of polluted F− ions. Fluoride content in coral skeleton was determined as a related Na concentration (NaF) using the Flame of Atomic Absorption Atom (FAAS) with spike method. Fe3+ and F− ions were mixed in the reactor with a coral skeleton to understand their effect on the coral growth. The coral absorbs F− ions in the coral growth with their effect on Fe's absorption rate. The addition of 1.5 g/L F− ions significantly reduces the coral growth by 25%. The coral skeleton can be used to control Fe and F− in the seawater. [ABSTRACT FROM AUTHOR]

Indonesian government has committed to increase exploration of wasters potential. Microalgae is an excellent water organism which high potential converted to biodiesel. Moreover, microalgae have a better photosynthetic ability than ordinary plants. Thus, microalgae can take part in preventing global warming by reducing carbon dioxide levels in the atmosphere. Recent research has successfully isolated several microalgae isolates from water area in East Java. However, they had not been characterized yet. Therefore, the aim of this research was to characterize two of those isolates in terms of potential as a feedstock of biodiesel production. The results showed that based on phenotype analysis, it could be concluded that Kelp I and Kelp IV were Prochloron sp. and Chlamydomonas sp. Prochloron sp. grew up optimally within 16-18 days, while Chlamydomonas sp. had an optimum growth at 13-18 days. The lipid yield of dried microalgae is 31.85% and 46.86% for Prochloron sp. and Chlamydomonas sp., respectively. Fatty acids composition in both Prochloron sp. and Chlamydomonas sp. were dominated by palmitic acid, which is very good for biodiesel synthesis. [ABSTRACT FROM AUTHOR]

The 1,8-dioxo-octahydroxantene has many derivates. One of those is 9-(4-hydroxyphenyl)-3,4,6,7-tetrahydro-2H-xanthene-1,8(5H,9H)-dione. This compound has been successfully synthesized from 4-hydroxybenzaldehyde and 1,3-cyclohexanedione. This reaction has been catalyzed by lime and lemon juice under the free solvent condition. It is assumed that citric acid in both materials has a role in catalyzing this reaction. The advantages of using them as catalysts are biodegradable, environmentally safe, and cheap. Besides that, the synthesis of this compound only required one reaction stage, and the product was easily purified. The structure of the pure product was determined by FT-IR, H-NMR, and GC-MS. The antioxidant activity of this compound was investigated by the DPPH method. This compound had an antioxidant activity with inhibition percentage over 53.42%. [ABSTRACT FROM AUTHOR]

Synthesis of 9-(4-bromophenyl)-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione (compound 1) using lime and lemon juices as catalyst under free solvent condition has been successfully done. Both fruits contained citric acid, which operates as an acidic catalyst. The structure of compound 1 was confirmed by IR, H-NMR, and MS spectra. The use of the natural product as a green catalyst has some advantages, that is eco-friendly, cheap, high availability, and biodegradable. DPPH methods were used as methods to determine the antioxidant properties of compound 1. This compound has properties as antioxidant with inhibition percentage of 59.20%, 65.38%, 67.41%, 68.53%, 70.0% at 2, 4, 6, 8, and 10 ppm respectively. [ABSTRACT FROM AUTHOR]

We determined the interferences of Ca2+ ions on Fe analysis in the sea sediment. The leached Ca from the coral skeleton affect the Fe ions to reduce the accuracy and precision of Fe analysis in sea sediment using flame-atomic absorption spectrophotometry. The Fe from sediment was leached by the optimized microwave BCR and Tessier methods. The Ca2+ ions (200, 500, 800 ppm) were added in the sediment fraction and then Fe concentrations were determined by FAAS. The results showed that Ca2+ ions interferences of Fe in all sediment fractions using BCR and Tessier methods. The interference of Ca2+ ions in the optimized microwave BCR method released the higher Fe concentrations. The addition of Ca2+ ions with concentrations of 200, 500, and 800 ppm in the optimized microwave BCR and Tessier methods obtained total concentrations of Fe 3737, 3700, 3658 mg/kg, and 1775, 1809, 1815 mg/kg, respectively. The presence of Ca formed the refractory oxy compounds due to the reaction between oxygen gas and Ca atoms in the air-acetylene flame of the FAAS flame. This suggested the interferences Ca reduce the accuracy in determining Fe concentration in the detector of FAAS. [ABSTRACT FROM AUTHOR]

Cooking oil waste is quite abundant in the community, and this is a threat to the environment. Exploration of biodiesel feedstock is very important to reduce production costs, such as from waste cooking oil. The utilization of heterogeneous catalysts is more environmentally friendly than homogeneous catalysts such as alkaline bases. Ultrasonic wave cavitation will accelerate the reaction rate. The purpose of this study was to determine the optimum conditions for transesterification of used cooking oil with CaO_K2O catalyst using ultrasonic wave, and to characterize and identify the synthesized methyl ester. Several stages in this research are: (1) activation of CaO_K2O catalyst, (2) purification of used cooking oil (3) Transesterification using ultrasonic waves with temperature variations (55, 60, and 65) °C, and the concentration of CaO_K2O catalyst (6, 8 and 10)% w/w, and (4) characterization of the results carried out including density, viscosity, acid number, refractive index, and identification of the results by gas chromatography-mass spectroscopy (GC-MS). The results showed the optimum conditions for methyl ester synthesis using ultrasonic waves at a temperature of 65 °C and a concentration of 8% w/w with a yield of 92.37%. The methyl ester components of cooking oil are 6.37% methyl myristate, 4.34% methyl palmitoleate, 24.62% methyl palmitate, 49.44% methyl oleate, 10.72% methyl stearate, and 4.51% methyl arachidate. The characters of the synthesized methyl ester with density (0.854 ± 0.000) g/mL, viscosity (5.501 ± 0.032) cSt, acid number (0.550 ± 0.000) mg KOH/g, and refractive index 1.447 ± 0.00085 and synthesized methyl ester potential as biodiesel. [ABSTRACT FROM AUTHOR]

Synthesis of methyl ester from tobacco oil (Voor-Oogst) with potassium hydroxide (KOH) catalyst using ultrasonic waves and its potential test as biodiesel had been done. The tobacco seeds were obtained from Probolinggo, East Java, Indonesia. The stages in this study were: 1. Isolation of tobacco seed oil using n-hexane as a solvent; 2. Esterification process; 3. Transesterification with some variation in the KOH concentration as a catalyst; 4. Characterization of the synthesized methyl ester; and 5. Identification of the synthesized methyl ester components by GC-MS. The results showed that the synthesis of methyl esters through the transesterification method using three KOH concentration variation 0.8%, 1% and 2% w/w and ultra-sonic waves produced biodiesel with yields of 77.45%, 84.55%, and 80.72% respectively. According to SNI criteria of biodiesel, methyl esters from tobacco oil met the biodiesel standard with the viscosity of 4.44 cSt, density of 0.865 g/mL, refractive index of 1.45, acid number of 0.56 mg/g. The main constituent of methyl ester of the biodiesel were methyl palmitate, linoleic, oleic and stearic with the percentage of 18.72%; 30.76%; 27.26% and 9.35%, respectively. [ABSTRACT FROM AUTHOR]

This research aims to know the effect of the use of Study History Sheet (SHS)-based LC-5E learning models on student learning outcomes in learning reduction oxidation (redox) reactions. The design of research used was a quasi-experimental with posttest only design. The research sample was grade X senior high school students that was determined using a cluster random sampling technique. The results showed that there is an effect of the use of SHS in learning outcomes of grade X senior high school students that is categorized very high criteria (correlation coefficient of 0.94). The average students learning achievement taught by SHS-based LC-5E learning model (86.4) is higher than that of taught by LC-5E learning model without SHS-based (82.7). It means that the use of the SHS-based LC-5 blended learning model can improve student learning outcomes in studying redox reactions. Future studies should utilise another subject to consider using this approach in teaching learning. [ABSTRACT FROM AUTHOR]

This study aims to identify students' misconceptions about reaction rate using Google Forms three-tier tests. The integration of three-tier tests into web services has previously been developed by Tan, et al (2019). The digitalization of the three-tier tests allows researchers to organize the grouping of reasons in the second-tier according to the choice of answers in the first-tier. The web service used on the test is Google Forms. For this reason, 21 Google Forms three-tier test items were given to 11th-grade students with a sample of 174 respondents. This research uses descriptive research design. the research steps undertaken include : (1) reviewing the literature, (2) compiling multiple-choice open-ended tests, (3) validation testing by experts, (4) testing multiple-choice open reasoning tests, (5) compiling items Google Forms three-tier tests questions, (6) expert validation test, (7) Google Forms three-tier tests, (8) quality analysis and revision of Google Forms three-tier test questions, (9) data collection using a Google Forms three-tier tests, (10) Google Forms three-tier tests data analysis for identification of misconceptions. Analysis of the results of the study showed that the highest percentage of misconceptions experienced by students about the concept of factors affecting the rate of reaction. The conclusion is that the Google Forms three-tier test can be used to identify students' misconceptions about the reaction rate. [ABSTRACT FROM AUTHOR]

Two facts, namely the industrial development in various fields and limited natural dyes, have led to an increase of synthetic dyes uses which have the potential to produce hazardous wastes if not managed properly. Some efforts to process liquid waste, especially synthetic dye waste can be done in many ways. A simple but supposedly effective way is to utilize magnetic nanoscale adsorbent material as a waste processing agent. The purpose of this study was to synthesize salicylic acid-modified magnetite nanoparticles and apply them as a liquid waste processor, especially Malachite Green waste. Malachite Green is a dye that is often used in the industry. The magnetic properties possessed by magnetite material are beneficial in material recovery. The main stages of the study include the synthesis of magnetite nanoparticles by electro-oxidation of iron in water; modification of material with salicylic acid; characterization of synthesized materials with XRD, FTIR, SEM, and BET; and Malachite Green waste treatment process by salicylic acid-modified magnetite. The results of XRD, FTIR, and SEM characterization showed that the salicylic acid-modified magnetite nanoparticles were successfully synthesized. The results of BET characterization provide a particle surface area of 88 m²/g which shows the potential of the material as an adsorbent. The application of the material as an adsorbent successfully absorbed 88% Malachite Green with an adsorption capacity of 15.5 mg/g at room temperature in 120 minutes. [ABSTRACT FROM AUTHOR]

Acidification and coagulation are important processes in making the cheese from cow's milk. The concentration of starter and rennet affect the characteristics of the cheese. This study aimed to determine the effect of starter and rennet concentrations on the cheese of good quality and then determine the yield, water content, protein content, and organoleptic test of its cheese. Variation of starter was applied in the concentration of 1%, 2%, and 3% (v/v), and the rennet at different concentrations (0.010%; 0.025%; and 0.040%(v/v)). ANOVA and Kruskal-Wallis test results showed that the concentration of starter and rennet affected the color, texture, and protein content, while the rennet concentration only affected the water content (P <0.05). The cheese yield, taste, and aroma were less affected (P> 0.05). Mann-Whitney Test results indicated that the cheese produced a soft texture, yellowish-white color, the characteristic aroma of cheese, and the typical saltiness of the cheese. The cheese yield, water content, and protein content produced were 13.46-19.19%, 50.87-66.05%, and 3.86-9.73%, respectively. [ABSTRACT FROM AUTHOR]

Fe in water is a material that is difficult to degrade, so it can last for a long time and stays in sediments. Fe in sludge is usually caused by anthropogenic factors, including industrial, port, and agricultural waste. Heavy metals in amounts above the threshold level can be dangerous for the aquatic ecosystems of living creatures in the vicinity. The Tessier-microwave method divides sediment into five fractions, the ion exchange fraction, the carbonate bound fraction, the reduction fraction, and the oxidation fraction are non-resistant fractions, while the residual fraction is the resistant fraction. Each fraction shows its attachment to sludge sediment sediments. This research was conducted to determine the concentration of Fe, fractionation, and distribution of Fe attachments in each fraction, and to find out the similarities of reactions that occur in sludge leaching in the Prigi Beach area. Heavy metal concentration in the sludge sediment of the Prigi beach areas on the resistant fraction was greater, which is an average percentage of attachment distribution of 74.91%, while the percentage of attachment to the non-resistant fraction was 25.09%. Fe is distributed in fractions 3, 4, and 5 with varying levels. Fe in the non-resistant fraction in only bound in the reduction and oxidation fractions. The high percentage of resistant fractions shows that the most significant contributor to Fe in Prigi comes from natural sources. [ABSTRACT FROM AUTHOR]

Calcium is a metal whose presence can be used as an indicator of ocean acidification. Acidification of sea water occurs due to the effects of global warming. The form of Ca in calcium carbonate can be leached under acidic conditions. The assessment of Ca is very important to control of coral bleaching. This research used the BCR microwave method to investigate the residence of Ca bound to each fraction. The results showed the residence of 73 percent in fraction 1 and 22 percent in fraction 4 from total of Ca in sludge sediment. The highest level of Ca (64350.27 mg / kg) in the fraction 1 was compared with those in fraction 2, 3, and 4 indicating the easily mobilized of bleaching Ca in seawater and then deposited in sludge sediment. [ABSTRACT FROM AUTHOR]