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Valorisation of glycerol through catalytic conversion conducted using KOH base catalysts with a mass ratio of KOH/glycerol of 0.08 (w/w) was carried out at temperature variations of 230 °C and 300 °C with feedstock variations of pure glycerol (98%) and crude glycerol with a total reaction time of 2 hours. Crude glycerol was obtained from the by-product of biodiesel transesterification from crude palm oil (CPO) using a KOH catalyst of 1% by weight of crude palm oil with variations in CPO:methanol such as 1:3, 1:6, and 2:1, which were performed at 60 °C for 4 hours at stirring speeds of 400 rpm. The largest percentage of crude glycerol conversion was obtained from the variation CPO: methanol (2:1) of 30.67%. The GC-MS characterization of glycerol catalytic conversion products revealed that the highest yield percentage is on the variation of pure glycerol feedstock at 230 °C, with the long-chain hydrocarbon fraction in the form of stearic acid compounds having the highest abundance percentage (abundance percentage of 26.54%). Catalyticconversion of pure glycerol feedstock variations at a reaction temperature of 300 °C resulted in formic acid (abundance percentage of 24.68%) with the greatest abundance and oxalic acid (abundance percentage of 2.28%). Meanwhile, the feedstock variation of crude glycerol produced 2-propenoic acid (abundance percentage of 5.04%) and acetone (abundance percentage of 2.84%), as well as hexadecanoic acid with the largest abundance percentage (32.04%). These findings demonstrated that catalytic glycerol conversion with KOH catalysts produced compounds with a wide range of industrial applications. [ABSTRACT FROM AUTHOR]

Sugarcane trash is abundant underutilized biomass that has high hemicellulose content as a source of xylose. Inorganic salts, such as Al2(SO4)3 and FeCl3 could act as acids and hydrolyze biomass components, especially hemicellulose. The objectives of this study were to explore the use of different amounts of the two catalysts in the hydrolysis of sugarcane trash hemicellulose using two heating methods, an autoclave or microwave digester, with water or 1% oxalic acid as a medium. The amount of catalyst was 50 and 100 µmol/ g biomass, while the heat treatment was at 121 °C for 30 min in the autoclave or 180 °C for 5 min in the microwave digester. Results of the study show that the use of microwave digester with a catalyst of 100 µmol /g biomass in an acid medium resulted in the highest biomass solubilization (40.2-41.2%). The highest reducing sugar concentration (28.1-29.8 g/L) was obtained using an autoclave or microwave digester with an acid medium and FeCl3 catalyst (100 µmol /g biomass). However, if water medium is used, the highest solubilization and reducing sugar concentrations (24.1% and 15.6 g/L, respectively) are those from the process with Al2(SO4)3 catalyst (100 µmol /g biomass). The addition of catalysts to an acid medium does not increase or even decrease xylose concentration. Meanwhile, the addition of Al2(SO4)3 catalyst (100 µmol /g biomass) could increase xylose concentration from 0.1 to 2.4 g/L and xylooligosaccharide concentration from 1.4 to 6.3 g/L when the hydrolysis is conducted in water medium using a microwave digester. Hydrolysis using Al2(SO4)3 catalyst in a water medium is more promising as an alternative to acid hydrolysis in xylose production than using FeCl3 catalyst. The higher amount of catalyst resulted in higher biomass solubilization, reducing sugar and xylose concentrations in the hydrolysate. Processes using microwave digester give better results of hydrolysis, including xylose recovery. [ABSTRACT FROM AUTHOR]

Recovery of rare earth element from acid mine drainage has been extensively explored worldwide as it can be potential alternative sources in the future. Malaysian acid mine drainage was previously considered as a liability to mining industry due to the environmental issue but found to be new potential asset for the country soon. The main objective of this work was to conduct a preliminary study on recovery process of rare earth element from Malaysian acid mine drainage. AMD is sampled from iron ore areas which containing significant amount of pyrite and contained 1.84 ppm of total rare earth elements, 61.71 ppm Fe, 49.53 ppm Al and 35.62 ppm Mn. The pH value of acid mine drainage was controlled in narrow-range by using sodium hydroxide solution to conduct selective precipitation process. Selective precipitation of acid mine drainage from pH range of raw sample till pH above 12 was conducted in this study. Further separation process of precipitated rare earth element was conducted via re-dissolution and oxalic acid precipitation process in this study. A simple process flow for recovery of Malaysia acid mine drainage was developed as baseline study in order to enhance the recovery efficiency in the future. [ABSTRACT FROM AUTHOR]

An experiment has been carried out on improving the quality of serpentine from Banjarnegara by a leaching method using sulfuric acid and oxalic acid. Prior to the leaching process, the serpentine was ground using a pot mill to attain-100 mesh particles. Then the fine serpentine was weighed 100 g for a leaching process using sulfuric acid and oxalic acid. For leaching serpentine, it is carried out in 500 ml of distilled water with addition of acids into a beaker with a magnetic stirrer hot plate. The stirring was conducted at a temperature hot plate of 150°C for an hour until the iron impurities adhered to the magnetic stirrer and the colour of the solution was yellow. After that, the serpentine slurry was cooled down at room temperature. This serpentine slurry was then washed with distilled water until it is clean/clear to remove the acid solution to a neutral pH. Furthermore, the serpentine slurry is decanted to precipitate or separate iron impurities (Fe2O3) from the processed serpentine. From this decantation process, some of the iron contents was separated from the serpentine, where the recovery rate of serpentine ranges from 47.65 – 50.27 %. The mineral analysis in the sample was carried out by XRD. Meanwhile, the chemical composition test was used to determine the effectiveness of the leaching process. Heated at 1150°C, the original serpentine showed reddish brown in colour while the leached one is grey-white. This can be an indication that the iron oxide content has decreased. The processed serpentine material can be used as a raw material in the manufacture of ceramic tiles and other ceramic products. [ABSTRACT FROM AUTHOR]

Oxalic acid is one of the important organic acids that has many uses in the field of medicine, agriculture, industry and others. Our current study aims to produce this acid in a safe, fast and cheap way by adopting microorganisms, especially Candida albicans. C. albicans was isolated from the mouth and from the surrounding environment, and then the isolates were screened for the purpose of obtaining the best productive isolates, then a culture medium was prepared from wheat bran as an alternative medium for laboratory media, and the effect of some factors such as temperature, pH, and salts on the percentage of oxalic acid production was tested. The results showed that the isolates from the mouth were the best in the percentage of oxalic acid production compared to the environmental isolates. pH 6 and the best salt is MgSO4.7H2O. All of the above confirms the high ability of C. albicans to produce oxalic acid. Wheat bran medium can also be adopted as an alternative medium for the production of this acid according to the aforementioned conditions. [ABSTRACT FROM AUTHOR]

The potential of Rare Earth Elements (REE) in Indonesia is very abundant, its locations are spread across Sumatra Island (Bangka Belitung Province), Kalimantan Island, Sulawesi Island and Papua Island with an estimated total potential of 1.5 billion tons. Global demand for rare earth elements is increasing in line with the increase of electronic equipment, permanent magnets for hybrid electric car applications, rechargeable batteries, lasers, hydrogen storage tanks, superalloy materials for the aerospace industry, television, computer screens, as well as for the development of alternative energy like a fuel cell. One of the minerals containing rare earth metals is monazite. The process of making REE concentrate from monazite can be done through the stages of decomposition, partial dissolution, and precipitation. In this study, it was focused on the precipitation stage using oxalic acid (H2C2O4) as reagent. The purpose of this study was to determine the best concentration of oxalic acid, temperature, and time of precipitation by looking at the results of oxalate and thorium recovery. In this study, feed chloride solution (REE-Cl3) containing REE 100.93 g/L and thorium 0.047 g/L was precipitated with oxalic acid as reagent, using variable mole ratio REE: oxalic acid, at 1: 1.5; 1.6; 1.7; 1.8; 1.9; 2, temperatures of 30, 40, 50, 60, 70, 80 °C, and precipitation times for 15, 20, 25, 30, 35, 40, and 50 minutes. The slurry was filtered to obtain the filtrate and residue. The filtrate was characterized using ICP-OES, and spectrophotometer UV-VIS. The result showed that the highest REE recovery was 99.06 % and the lowest thorium recovery was 89.71 %, with the condition mole ratio of REE : oxalic acid was 1: 1.7, temperature was 60 °C, and the precipitation time was 15 minutes. [ABSTRACT FROM AUTHOR]

Crosslinking of chitosan microcapsules is important for control purposes according to their applications and influences their mechanical, thermal, and chemical stability, and tripolyphosphate (TPP) has been predominantly utilized in the electrospray technique for their production. The properties of chitosan microcapsules produced by electrospraying technique and cross-linked with a mixed cross-linking solution (OxPh), consisting of oxalic acid and sodium phosphate dibasic were studied. The formed capsules were characterized by SEM, XRD, FTIR, and the stability and mechanical properties of the capsules were studied. The cross-linked microcapsules provided smooth morphology and exhibited mechanical strength of 80% in the undried state, with dried state mechanical strength of 21.2N as against 19.8N of TPP cross-linked chitosan microcapsules. The microcapsules were also stable in a pH solution of 3.0-5.0. [ABSTRACT FROM AUTHOR]

Hemicellulose in Oil Palm Empty Fruit Bunches (EFB) can be hydrolyzed to xylose and then converted to furfural via dehydration. Generally, furfural production uses sulfuric acid as a solvent. However, this solvent has toxic and can cause corrosion in equipment. This study developed a furfural production process using a green solvent called deep eutectic solvent (DES). DES was synthesized by mixing choline chloride and oxalic acid with a mole ratio of 1:1. The temperature and processing time were varied at 100, 120, and 150oC, respectively, to obtain optimal furfural. The optimal furfural concentration was reached 7.72 g/l at 150oC for 30 minutes. This process can be an alternative environmentally friendly furfural production process. [ABSTRACT FROM AUTHOR]

The present work aimed to understand and investigate the relations between precipitation, chromium depletion, and degree of sensitization in 5A and 6A grade cast duplex stainless steel (DSS) at sensitized and non-sensitized conditions. Due to the high corrosion resistance properties of DSS, it is very well suited for high corrosive environments. Samples at three dissimilar heat treatment conditions are chosen by Thermo-calc software and Intergranular corrosion (IGC) effect was tested using double loop electrochemical potentio-dynamic reactivation (DL-EPR) test. In combination with microstructure observation using optical microscopy, the surface variations were investigated using scanning electron microscope (SEM) attached with electron dispersive X-ray spectroscopy (EDX) and X-ray diffractometry (XRD). Oxalic acid etch test and DLEPR tests were performed in order to detect the level of susceptibility and sensitization to IGC. The results revealed that the precipitation of deleterious phases due to the presence of more alloying elements in 6A grade DSS contributed to the reduction of IGC resistance. [ABSTRACT FROM AUTHOR]

Euphorbia hirta L. was identified as containing secondary metabolite compounds like terpenoid, coumarin, lignin, flavonoids, and phenolic compounds. The plant also has pharmacological activity as an antioxidant, antiinflammatory, and antibacterial. In this study, extraction is using natural deep eutectic solvent (NADES). NADES can be tailored concerning polarity, so this solvent is selective to extract secondary metabolite compounds. Ultrasound-assisted extraction (UAE) is often combined with extraction using NADES. This study aims to obtain the best NADES composition to extracting flavonoid and phenolic compounds as well as those with the strongest antioxidant activity and found out the correlation between TFC and TPC values with IC50 in extracts. The NADES was prepared with heating and stirring methods. The NADES was used is choline chloride : citric acid (ChCa), choline chloride: maleic acid (ChMla), choline chloride : malic acid (ChMa), choline chloride : lactic acid (ChLa), and choline chloride : oxalic acid (ChOa). NADES ChMla is the best composition for extracting flavonoid and phenolic compounds. The TFC and TPC values of ChMla extract were 9.613±0.0258 mg QE/g DW and 125.105±0.9674 mg GAE/g DW. Extracts from NADES ChMla also have the strongest antioxidant activity with an IC50 value of 30,438 mL/L. There is a strong correlation between the total flavonoid content with IC50 values, as well as a very strong correlation between the total phenolic content and the IC50 value. [ABSTRACT FROM AUTHOR]

The synthesis of sodium manganese oxide has been carried out by modifying the sol-gel method used to synthesize lithium manganese oxide. The precursors used were sodium bicarbonate and manganese oxide. The sol-gel process used was water solvent, oxalic acid as a chelating agent and chitosan as the template. Thermal decomposition and formation zone obtained from simple thermal analysis using a furnace and precision digital scales. Crystal properties and morphology were analyzed using XRD. Based on the XRD spectrum, sodium manganese oxide crystals have been formed successfully. This material has the potential as a local alternative material for batteries that are cheaper than lithium-ion battery technology. [ABSTRACT FROM AUTHOR]

Porang (Amorphophallus oncophyllus Prain) is a promising food security crop in West Nusa Tenggara since it contains a lot of carbohydrates. However, the corm's high calcium oxalate level has made it difficult to use it in the food business. The objective of this study was to examine the influence of fermentation technology on calcium oxalate level and other porang flour properties. Fresh porang tubers from North Lombok were subjected to a spontaneous fermentation process for various durations of time, including 0, 12, 24, 36, 48, and 60 hours. The levels of oxalic acid, pH, total lactic acid bacteria, and the color of porang flour were all measured in this research. The findings of this study showed that fermentation of fresh porang tubers lowered the calcium oxalate content of flour and resulted in a brighter flour color when compared to unfermented corm flour. Although the oxalate concentration was slightly greater than the standard, the flour produced from the treatment fulfilled the quality requirements for porang flour. To increase the safety and quality of local porang flour, further research is required. [ABSTRACT FROM AUTHOR]

NMC is a lithium-ion battery that combines three primary metals, namely Nickel, Manganese, and Cobalt. Manganese metal is used in the form of manganese sulfate (MnSO4). This research has studied the effect of adding alkali in the precipitation of impurities from the solution of manganese ore leaching on the crystals of MnSO4 as raw material for the manufacture of NMC. Some manganese ores are leached using oxalic acid as a reducing agent in a sulfuric acid atmosphere. Then, the impurities (mainly iron) precipitation from pregnant leached solution was carried out with pH adjustment using various alkalis. The alkalis used in this study were NaOH, NH4OH, and Ca(OH)2. The MnSO4 products were characterized using XRF and XRD. The results showed that the use of Ca(OH)2 in the precipitation of iron and other impurities from the pregnant leached solution could provide better MnSO4 crystals than the use of NaOH and NH4OH. [ABSTRACT FROM AUTHOR]

The largest solid waste from crude palm oil plant is Oil Palm Empty Fruit Bunch (OPEFB). OPEFB contains cellulose, lignin, and hemicellulose. Cellulose has been utilized in some biochemical and materials, but hemicellulose was not optimally used yet. Hemicellulose can be converted to xylose and used as feedstock for furfural production. The aim of the research was to find the best way to make furfural from xylose in an aqueous deep eutectic solvent (DES). Choline chloride was mixed with oxalic acid to form DES. The S/L ratio (xylose and DES) was varied in 5, 7.5, and 10%. The process condition includes temperature and time reaction in 80-120°C and 1-3 hours, respectively. The optimal furfural yield was obtained 38.53% by the process at 10% substrate in 105°C for 120 min. This result was promised to utilize xylose from lignocellulose to get a circular economy from lignocellulosic biomass utilization. [ABSTRACT FROM AUTHOR]

Anise is considered one of the economically and medically important plants that used by many peoples in the past, including Arab peoples, where has many compounds with useful properties. The aim of the current study was to detect the important chemical compounds in anise extract by hexane solvent using the GC-MS technique to show the types of compounds that have economic and medical importance for isolated from this plant in the future, in addition to the activity of antioxidation of this extract. Methods: In the experiment, plant extraction was prepared by used Soxhlet, were using hexane as a non-polar solvent, Then the compounds were detected by the GC-MS technique with the presence of additives Pyridine and MSTFA, also use DPPH and FRAP assays to examine the antioxidant activity of the extract. there was 25 chemical compounds, which were successively diagnosed according to the speed of their appearance depending on the retention time, Ethylphenyl acetate was found with the highest concentration among the compounds (26.988%), followed by Eugenol with a higher retention time and less concentration (16.509%), while Anethole was found with retention time higher than the two previous compounds, but less concentration (9.962%). Also found compounds not previously registered within the chemical content of the anise plant (Isobutyltrimethoxysilane Ethyltrimethoxysilane , Oxalic acid and Octatetracontane), which is due to the different conditions and the importance of using additives. As for the antioxidant efficacy, the high concentrations of anise extract showed great efficacy that was not significantly different from ascorbic acid, where (80, 90 and 100mg/ml) of anise extract showed (93.07%, 95.23% and 96.91%) in DPPH compare to (94.88%, 97.20% and 98.37%) for ascorbic acid respectively, also (90 and 100mg/ml) showed (0.301 and 0.390) in FRAP compare to (0.358 and 0.418) for ascorbic acid as control, and they were also close when compared with each other. As for the remaining concentrations, they showed weakness in their ability to scavenge roots OF DPPH and reduce of FRAP to show significant difference when compare to ascorbic acid. It was concluded from the current study that there are many compounds in the content of Anise plant that have high economic and medical importance that can be used for scientific and research purposes, in addition to the presence of new compounds that can be attributed to it the effectiveness of this plant. In addition, there is significant antioxidant activity of anise extract may be very important in the scientific field. [ABSTRACT FROM AUTHOR]

The synthesis study of zirconia (zirconium oxide) from zirconium oxide chloride (ZOC) resulted from the Kalimantan zircon sand process by precipitation and sol-gel methods have been carried out. This study aims to increase the added value of zircon sand to zirconia which has a higher economic value. In the precipitation method, zirconium in ZOC was precipitated as zirconium hydroxide at pH 10 with ammonia, dried, and calcined at 900 °C for 3 hours. In the sol-gel method, zirconyl in ZOC was made sol-gel of zirconyl-oxalic with oxalic acid, with a ratio of ZOC: oxalic acid=1 M: 0.5 M. The sol-gel was dried at 110 °C, then calcined at 1000 °C for 3 hours, zirconia was obtained. Zirconia was tested for composition using the XRF method and characterization with XRD and PSA methods. In the precipitation method, zirconia was obtained with a composition of zirconium oxide (ZrO2): 95.422%; HfO2: 1.443%; SiO2: 0.535%; Al2O3: 0.362%; Na2O: 0.262%. The dominant compound was zirconium oxide and the particle size escaped 74 µm. In the sol-gel method, zirconia was obtained with compositions including ZrO2: 94.539%, HfO2: 2.844%, P2O5: 2.629%, CaO: 0.269%. With the XRD method, the dominant compound was zirconium oxide with PSA obtained the diameter particle size (525.5-539.0) nm. So with the sol-gel method, zirconia with a smaller particle size was obtained. [ABSTRACT FROM AUTHOR]

Lithium-ion battery (LIB) as one of the important energy storage devices and attracts attention due to its high specific capacity and long cycling life. Among several cathode materials studied, spinel LiMn2O4 is promising due to its great advantages such as abundant precursor, low cost, environmental friendliness, high working voltage and intrinsic thermal stability under severe environmental conditions. In this study, LiMn2O4 was prepared from manganese-based fertilizer with the addition of oxalic acid, sodium hydroxide, and soda ash as precipitant. All of the samples were characterized using XRD, FTIR and SEM. The LiMn2O4 structure was successfully formed based on the XRD test results. SEM results LiMn2O4 showed that the material has micron sized polyhedral shape, specifically octahedral shape. EDX study shows there is no impurities. Charge and discharge analysis of as obtained LiMn2O4 using artificial graphite as the anode shows a charge capacity of 116 mAh/g and a discharge capacity of 115 mAh/g which is an outstanding result since an economical and abundant fertilizer was used as the main raw materials. [ABSTRACT FROM AUTHOR]

Lithium ion batteries (LIBs) is currently the most promising energy storage device for technologies such as cellphones, gadgets, and electrical vehicles. Nowadays, LiCoO2 (LCO) type cells is still used due to its excellent performance even with high amount of cobalt. To reduce the overall production cost, a simple process with high scalability is proposed. In this study, a kilogram of LiCoO2 cathode materials were produced using room temperature cobalt crystallization of cobaltous solution. The effect of precipitating agents such as sodium hydroxide, oxalic acid and soda ash towards the material characteristics were deeply investigated. As obtained powders and products were characterized using XRD, FTIR, and SEM. Cobalt hydroxide, cobalt oxalate and cobalt carbonate were successfully synthesized based on XRD and FTIR study. Layered structure of LiCoO2 powders is confirmed by XRD study. SEM images of LCO products show a unique grape-like morphology with micron-sized secondary particles. Based on charge-discharge characteristics, the highest initial discharge capacity of 121 mAh/g is obtained by LCO from cobalt hydroxide with capacity retention of 24% after cycled for 230 cycles using 1C-2C-4C-8C-16C-30C current rates. [ABSTRACT FROM AUTHOR]

Prediction of the reactivity of azolides of aliphatic dicarboxylic acids in interaction with nucleophilic and electrophilic reagents has been carried out. The most stable conformations of these molecules (MMFF molecular mechanics method) and the surfaces of nucleophilic and electrophilic susceptibilities (DFT DGauss B88-PW91 method) were calculated. It has been shown that the reactivity of oxalic and malonic acid diazolides with nucleophilic and electrophilic agents changes depending on the number of nitrogen atoms in the heterocycle. [ABSTRACT FROM AUTHOR]

Lithium ion battery (LIB) currently becomes of important aspect in modern life, especifically due to demands from electronic devices and e-vehicle industries. Because of its superlative performance, among various types of LIB, NCA battery has widely used in many applications. Nickel in the battery cathode contributes up to 48% and tends to shift towards higher nickel content due to its superior energy density. However, the battery will come to an end after a certain period of usage and the waste might cause environmental problem in the future. Due to its valuable metal content, a recovery unit is needed in order to recycle the metals including nickel. The present work focused on recovery of nickel from the remaining precipitates through a leaching process in oxalic acid following lithium recovery from NCA battery cathode. The research aimed to investigate the effect of temperature, S/L ratio, pH, and reaction time on the nickel recovery. Experimental result showed that lower pH and S/L ratio values as well as temperature rise to 60°C could improve the recovery. Meanwhile, above 60°C recovery seemed to decrease due to the rate of deposition of nickel is higher than the rate of leaching. The optimum leaching conditions was reached after 30 minute with S/L ratio of 5, at 57.68°C, pH 1 with the optimum recovery value of 63.34% analyzed using RSM method. The kinetics parameters were studied at the optimum condition and the data was used for kinetic model evaluation. The proposed kinetic model was suitable to approach the experimental data with a rate constant of leaching (k') of 0.9674 men−1 and rate constant of deposition (k2) of 0.0556 men-1. [ABSTRACT FROM AUTHOR]

The thermogravimetric analysis of membranes of anodic aluminum oxide (AAO) was carried out. The results showed that in the process of anodic growth, water molecules are adsorbed in the pores of Al2O3, the amount of which is determined by the anodizing voltage of aluminum. The relationship is revealed and the graphs of the relationship between anodizing voltage, annealing temperature, and weight loss of nanostructured membranes of AAO are presented. It has been established that the adsorption of water molecules on the surface of AAO is explained by the presence of a surface charge, which disappears after annealing at 200–300 °C. An increase in the amount of adsorbed water with an increase in the anodizing voltage from 20 to 40 V indicates a decrease in the surface charge density. [ABSTRACT FROM AUTHOR]

Anodic aluminium oxide (AAO) thin film electrodes were synthesized by using a single step anodizing method in 15 °C of 0.3 M oxalic acid at five different anodizing voltage ranging from 20 V to 60 V, respectively. The effect of anodizing voltage to the AAO dimensional properties were about to be investigated. Morphological observations were all done by FESEM where the measurements and calculation were made by using ImageJ and formulas. To ensure that the pore sizes were totally depended on the anodizing voltage, etching process were done at constant duration for all samples. The correlation between all AAO dimensional properties like pores size, interpore distance, wall thickness, pore density, percentage of porosity and nanoporous oxide thickness were presented in a linear graph. [ABSTRACT FROM AUTHOR]

The formation of surface defects in γ-Al2O3 obtained by pseudoboehmite calcination and plasticized with oxalic acids is reported. Physicochemical properties of the Pt-containing catalysts based on unpromoted and zirconium- promoted alumina were compared with their catalytic activity in dehydrocyclization of n-heptane. The introduction of Zr in the Pt/Al2O3 catalyst was shown to decrease the helium pycnometer density of alumina and Zr locates in defect sites of alumina. The catalyst selectivity increased with the introduction of zirconium. [ABSTRACT FROM AUTHOR]

Ideally, In super duplex stainless steel, there's a 1:1 ratio of microstructure austenite and ferrite phases. However, these phases depends on their composition and thermal history. This study aims to find microstructure characterization in 32760 Super duplex stainless steel after solution treatment at 1080°C followed by using Three different colling media, which is water, oil, and air at room temperature. the following methods will be used to investigate the ferrite-austenite structure and precipitates of secondary phases in stainless steel. The structure is studied under light microscope And SEM EDS. So far, the X-Ray Diffraction analysis has collaborated well with the above- mentioned microstructural investigation. the electrochemical etching are conducted in solutions of 10 % oxalic acid with 2V for 20 second. The experimental results showed character and morphology of these phases very markedly, as do the time for them to form and their effect in different cooling media, the microstructure in untreated specimen consists of (α) ferrite and (γ) austenite, a variations of result with three different cooling media after treatment showed movement of secondary phase and distribution of precipitation along the grain boundary [ABSTRACT FROM AUTHOR]

Humidity sensing at low RH level (below 30%) is challenging. Since sensing is a surface activity induced phenomenon, therefore, maneuvering shape and size of surface morphology in a customized fashion is a necessity. In this report, humidity sensing characteristics of sensors with different pore morphologies were thoroughly explored. For this, three capacitive sensors with identical electrode configuration and geometry were fabricated by anodization at different anodic polarization. Sulphuric-, oxalic- and phosphoric acids were used as electrolytes to vary the pore morphology. Pores of small, medium and large dimension in nanoscale were fabricated by varying anodic polarization. Sensor response characteristics have been examined and found that both the morphology and the electrolyte composition play a decisive role in determining the capability of the sensor of its measurement level in terms of RH. The prepared sensors having various degree of sensitivity show excellent response characteristics at low RH (3%-30%) detection. Besides, the performance of the sample anodized in oxalic acid is found optimum among the three samples. [ABSTRACT FROM AUTHOR]

Humic acid is biostimulan that has a negative charge and it is able to bind cations that are important in the process of plant growth. Red amaranth (Amaranthus tricolor L.) is one of vegetables that contains betacyanin which is a good source of antioxidants. However, the stem and leaves of red amaranth also contains oxalate which could inhibits calcium absorption in human's body. This study was aimed to evaluated the effect of humic acid on vegetative growth, yield, oxalic acid and betacyanin content of red amaranth (Amaranthus tricolor L.). Red amaranth seeds were germinated in a polybag containing top soil as growth media. Seedling were selected and humic acid were applied through foliage spray or soil surface when plants were at 2 weeks old. The concentration variation of humic acid were 0 mg/L, 5 mg/L, 20 mg/L or 35 mg/L and there were 5 replicates for each treatment. Vegetative growth observed were plant height and leaf number, yield observed were fresh and dry weight of shoot and root. Oxalic acid content was determined by permanganometric titration method, and the density of Ca-oxalate crystal was observed from stem cut preparate made by free-hand section technique. Betacyanin content was determined by HPLC (High Performance Liquid Chromatography), and chlorophyll content was determined by spectrophometric method. Data were analyzed by One Way ANOVA (Analysis of Variance), followed by Duncan Multiple Range Test with 95% confidence level. Results showed that humic acid of 20 mg/L applied through the leaves significantly increase plant height, leaf number, the fresh and dry weight of shoot and betacyanin content. Humic acid of 20 mg/L that was applied through the soil surface also significantly increased leaf number, both fresh and dry weight of shoot and root but reduced oxalate content. From this study it can be concluded that humic acid of 20 mg/L applied either through foliage spay or soil surface increased plant height, yield and betacyanin content but it reduce doxalate content of red amaranth. [ABSTRACT FROM AUTHOR]

Lithium Nickel Manganese Cobalt (LNMC) material has been successfully made using the coprecipitation method with precipitant agent oxalic acid and tartaric acid. The material that has been made is used as a cathode material in lithium ion batteries. Lithium ion batteries are made namely type 18650 full cell battery. Based on FTIR characterization, all precursors of nickel manganese cobalt (NMC) material have functional groups of hydroxide and carbonate. Based on the XRF results, the initial material making up the precursors, namely Ni, Mn and Co, is still present in the precursors. The XRD characterization results show that the material obtained has a LNMC spinel crystal structure which is like in JCPDS data No. 09-0063. The results of SEM show the LNMC precursor material is shaped like a spherical ball with impurities. The NMC cathode material is made into a full cell battery using graphite as the anode. Yield products show synthesis using oxalic acid as the highest yield. Battery test results obtained the best discharge value from LNMC-OA of 12.66 mAh/g. All samples were tested for specific capacity stability by carrying out charge-discharge for 100 cycles. And the results are all samples can still work on the 100th cycle. [ABSTRACT FROM AUTHOR]

Lithium-Ion (Li-Ion) battery is one of the secondary battery developed today. One of the important components of Li-Ion is cathode. Lithium Manganese Cobalt (LMCO), the last developed cathode material, had some disadvantage such as not resistant to high temperatures and short cycle performances. While Cathode material of LiNi0.6Mn0.2Co0.2.2O2 had some advantages of good structure stability, higher safety in high temperature and higher capacity. Here in this research the substance of nickel was inserted to the cathode material. The aim of the research was to synthesize LiNi0.6Mn0.2Co0.2.2O2 through simple and fast method of co-precipitation. Metal sulfate of Nickel, Manganese and Cobalt with a certain ratio were reacted with excess of Sodium hydroxide. Metal hydroxide formed was then precipitated with the co-precipitant of oxalic acid and pH adjuster of ammonia. Metal hydroxide obtained was then reacted with Lithium hydroxide in high temperature of solid state. The product yielded was characterized by XRD, FTIR and electrochemical performance analyzer. The result showed that LiNi0.6Mn0.2Co0.2.2O2 with the excess of 7% Lithium gave the good performance with the capacity of 115 mAh/gram. first, second, and third level headings (first level heading) [ABSTRACT FROM AUTHOR]

NiCo2O4 (NCO) nanostructures were synthesized by a simple hydrothermal method using three different surfactants such as ethylene glycol (EG), oxalic acid (OA) and ammonium fluoride (NHF). Morphology of the different nanostructured materials has been recorded using SEM. The electrochemical performance of the material has been demonstrated using three electrode system. NCO-EG urchin-like nanostructure exhibits the highest specific capacitance of 416 F g-1 at a current density of 0.5 A g-1 and it evolves73.3 % of capacitance retention at 10 A g-1. [ABSTRACT FROM AUTHOR]

Local pyrolusite ore from Waykanan regency (Lampung Province, Indonesia) has been treated by sulfuric acid leaching process using various reducing agents to produce manganese sulfate. The ore was detected as pyrolusite ore by XRD and contained Mn (36.8%), Fe (6.6%), and Si (4.1%). Various reducing agents such as molasses, glucosse, fructose, cane sugar, sodium sulfit, tannic acid, oxalic acid, citric acid, black tea, green tea, cellulose, sawdust of candlenut shell, sawdust of Acacia wood, sawdust of coconut shell, sawdust of Albizia chinensis wood, and H2O2 were used. From the experimental results, it can be found that tannic acid and oxalic acid were the most effective reducing agents for manganese leaching in sulfuric acid medium. The manganese recoveries were 100% when tannic acid and oxalic acid used as reducing agent, using 1 M of sulfuric acid and 5% of pulp density at 30°C of leaching temperature, 150 rpm of shaker speed, atmospheric pressure, and 8 hours of leaching period. [ABSTRACT FROM AUTHOR]

Cineole is one of monoterpene compounds usually produced from aromatic plants especially pine trees. It is mostly used for flavoring agent, aromatherapy, herbicide active compound, and pharmaceutical industry. Raw turpentine from pine tree has several derivatives, such as: α-pinene, β-pinene, limonene, δ-carene, camphene, terpineol, etc., with cineole being the component with the highest market price. However, there is no direct pathway to produce cineole from raw turpentine. Commonly, cineole presents as a side product from hydration of α-pinene or turpentine to terpineol and this process will not be economic. The distillation process to separate cineol from other components would be difficult and energy demanding because of its low concentration in the product. In this study, synthesis of cineole was conducted in a hope to obtain higher yield of cineole. The methods were managed in two reaction steps. First, the reaction of raw turpentine with water and acid catalysts to form terpineol for 3 hours at 85°C. Second, drawn off the water from the mixture then continue the reaction for 3 more hours at the same temperature to let terpineol isomerizes and becomes cineole. Based on the experimental results, it was found that using combined p-toluenesulfonic acid (PTSA) with several weak acids i.e. oxalic acid, citric acid, and formic acid, each at certain optimum composition, resulted 10.6% - 21.8% of cineole. These results are better than the previous generic process which cineole produced below 5%. [ABSTRACT FROM AUTHOR]

Modification of Pd/SO4/ZrO2/Al2O3 catalysts with HF, HNO3 and H2C2O4 acids during the support synthesis upon mixing of aluminum and zirconium hydroxides was studied. The amount of HF and HNO3 inorganic acids was found to exert a significant effect on the textural characteristics, such as specific surface area, pore volume and effective pore diameter. In the case of oxalic acid used at the concentrations characterized by variation of acidic modulus from 0.001 to 0.1, the pore structure parameters of the catalysts remained virtually unchanged. The XRD study demonstrated that modification with HF, HNO3 and H2C2O4 acids allows controlling the ratio of tetragonal and monoclinic phases of zirconia. It was found that among the tested acids the most pronounced effect on n-hexane isomerization was exerted by the introduction of hydrofluoric acid. [ABSTRACT FROM AUTHOR]

Lithium is one of the key elements in the development of batteries for electric car applications. Currently, the resources of the world’s lithium are derived from brine water and lithium mineral based on spodumene rock. Indonesia which is located in the area of the ring of fire, has potential brine water resources in some area, such as brine water from Bledug Kuwu, Central Java that used in this research. The purposes of this research are to characterize brine water, Bledug Kuwu and to investigate the influence of chemical solvents on Li, Na, K, Ca, Mg, Al, B ion precipitation from brine water. This research was done with 2 times the process of chemical precipitation that runs series as follows: 5 liters of brine water were chemically precipitated using 400 ml of 12.43 N oxalic acid and followed by chemical precipitation using 400 mL of 7.07 N sodium carbonate solutions. Evaporation and filtration processes were also done twice in an effort to separate white precipitate and filtrate. The filtrate was analyzed by ICP-OES and white precipitates (salts) were analyzed by SEM, XRD, and XRF. The result shows that oxalate precipitation process extracted 32.24% Al, 23.42% B, 22.43% Ca, 14.26% Fe, 3.21 % K, 9.86% Na and 14.26% Li, the following process by carbonate precipitation process extracted 98.86% Mg, 73% Ca, 22.53% Li, 82.04% Al, 14.38% B, 12.50% K, 2.27% Na. There is 63.21% lithium is not extracted from the series process. The SEM analysis shows that the structure of granules on the precipitated salts by oxalic acid form gentle cubic-shaped solid. In the other hand, oxalate precipitation followed by sodium carbonate has various particle sizes and the shape of crystals is fragments, prism and cube look like magnesium carbonate, calcium chloride, and calcite’s crystal respectively. This is in accordance with XRD analysis that phases of whewellite (CaC2O4.H2O), disodium oxalate (Na2C2O4), magnesite (MgCO3), calcium lithium aluminum (Al1.19 Ca1Li0.81), dolomite (CaCO3.MgCO3) appear in salt precipitated by oxalic acid. For salt precipitated by oxalic acid and sodium carbonate look peaks of dolomite and calcite (CaCO3) as main components. Lithium carbonate (Li2CO3) and calcium chloride (CaCl2) also are described with high peak intensity in this precipitation. A series of precipitation process shows that lithium is precipitated together with calcium, aluminum, and carbonate. [ABSTRACT FROM AUTHOR]

An attempt was made to synthesis the copper doped tin oxide (Cu-SnO2) nanoparticles by adopting different chelating agents (NaOH, KOH and C2H2O4) by Sol-gel process. The synthesized products were characterized by XRD, Photoluminescence (PL), Infra- Red (FTIR) and SEM analysis. The XRD confirms the formation of Cu-SnO2 shows the maximum peak at 33.8° with lattice plane (101). The PL peak at 361 and 382 nm due to the recombination of electron in conduction band to valence band infers the optical properties. The IR spectra correspond to the peak at 551 and 620 cm−1 attributed to the characteristics peak for Cu-SnO2 nanoparticles. The SEM images for all three Cu-SnO2 nanoparticles formed by three chelating agent (NaOH, KOH and C2H2O4) facilitates the formation mechanism and the chelating agent Oxalic acid results in formation of nano flowers with diverse layers orientated in random direction. Further SEM studies reveal that, the Cu-SnO2 nanoparticles formed by oxalic acid could posses high surface area with large number layered structured enables the better electrochemical properties and its applications. [ABSTRACT FROM AUTHOR]

As one of the solid waste generated by palm oil plantations. Oil Palm Fronds have the potential to be further processed into useful products since the presence of cellulose, hemicellulose and lignin. Hence, the objective of this study was to utilize oil palm fronds in producing oxalic acid through oxidation process using. To achieve the objective, this study assessed conversion of cellulose, yield and qualify of oxalic acid produced. Two stages are carried out. namely oxidation and crystallization. Assays on raw materials revealed the cellulose content of 29.2 percent. The largest yield of oxalic acid was 43.31 percent, the highest conversion of cellulose was 58.86 percent. FTIR and melting point analysis were employed in this study. These analyses indicated that the functional groups have reached the standard of oxalic acid with a melting point of 102.1 °C, which showed that the oxalic acid obtained was oxalic acid dehydrate. [ABSTRACT FROM AUTHOR]

The ciyptomelane-type manganese oxide catalysts have been prepared by sol-gel method based on the redox reaction between potassium permanganate and glucose or oxalic acid. These catalysts belong to a class of porous manganese oxides known as octahedral molecular sieves (OMS). The SEM results indicated that the marked difference between the morphology of the cyptomelanes produced from glucose and oxalic acid. The glucose precursor produces cotton-shaped morphology, whereas the oxalic acid precursor leads to the formation of the disk-like appearances. The XRD results indicated that the glucose precursor produces more crystalline cryptomelane than that of oxalic acid. The effect of catalyst dosage on methyelene blue degr adation was evaluated. Dye-decomposing activity was proportional to the amount of catalyst used, increasing of the catalyst amount leads to higher degradation of methyelene blue at short period of reaction . With different crystalline structures and morphology appearances of the cyptomelanes. however, the total degradation of methylene blue is relatively the same at 120 minute of reaction time with catalyst amount of 100 mg. [ABSTRACT FROM AUTHOR]

Calcium can be extracted not only from rocks but also from natural liquor such as seawater and brine water. In order to extract the calcium from seawater and brine water, oxalic acid was used in this research. Effect of variations of the volume of the oxalic acid at a constant concentration in seawater and brine water to produce calcium was investigated. The concentration of oxalic acid was 100 g/l and the variations of its volume were 2 ml, 4 ml, 6 ml, 8 ml, 10 ml, 20 ml, 30 ml, 40 ml, and 50 ml. The used seawater and brine water were firstly evaporated from 100 ml into 50 ml and then the oxalic acid was added into them with mixing to produce the calcium precipitates. The precipitates were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) and the filtrates were analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES). The SEM analysis showed that the precipitates from brine water were consisted of only calcium compound while from seawater sodium one was also found along with calcium compound. The XRD analysis showed that the calcium was present in the form of calcium oxalate for both seawater and brine water. The ICP-OES analysis of the filtrate from seawater precipitation showed that the its calcium content was decreased from 826.20 ppm to 0.04 ppm while from brine water, it decreased from 170.06 ppm to 1.96 ppm. These results showed that both seawater and brine water have the potential to be a raw material for calcium production. [ABSTRACT FROM AUTHOR]

Anodic aluminum oxide (AAO) membranes with 100 µm thickness were synthesized in oxalic acid solution under constant current density. Grown samples were annealed in 500-1250 °C range for 5 h in air. Average pore diameter was evaluated using quantitative analysis of SEM images and appeared to be within 78-86 nm diapason. It was found there was a broad emission band in the 350-620 nm region of photoluminescence (PL) spectra in amorphous membranes which is attributed to F-type oxygen deficient centers or oxalic ions. It was shown that intensive red emission caused by Cr3+ (696 nm) and Mn4+ (680 nm) impurities dominates in PL of AAO samples with crystalline α- and δ-phases after annealing at 1100-1250 °C temperatures. [ABSTRACT FROM AUTHOR]

Photoreduction of mercury metal using catalyst of oxalic acid from cellulose of rice husks (Oryza sativa L.) is one of methods to reduce toxicity properties of the mercury metal in the society. The purpose of this research is to enhance photoreduction of mercury metal using catalyst of oxalic acid from cellulose of rice husks (Oryza sativa L.) at various concentrations. Photoreduction process is carried out in a closed reactor equipped with UV light and magnetic stirrer. Analysis of the influence of oxalic acid is determined by adding 25 mL of Hg (II) 5 ppm without oxalic acid, 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 3 ppm, 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 6 ppm, 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 9 ppm, 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 12 ppm and 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 15 ppm. All treatments are followed by centrifugation for 15 minutes, then the concentration of Hg residual in the solution is measured by mercury analyzer. The research results showed that addition of oxalic acid concentration from the cellulose of rice husks (Oryza sativa L.) can enhance photoreduction of mercury metal. Optimum concentration reduction of mercury metal with addition of oxalic acid is obtained as many as 9-12 ppm. It can reduce the concentration of mercury metal (II) by 68.8% to 88.6%. [ABSTRACT FROM AUTHOR]

Recent studies on the potential toxicity of High Aspect Ratio Nanoparticles (HARN) has yet once again reinforced the health hazard imposed by asbestos fibres ranging from nano to micro size. Asbestos a naturally occurring fibrous mineral declared a Group I definite carcinogen by IARC (International Agency for Research on Cancer), a unit of WHO in the year 1987, has been extensively used since World War II to the near past for various commercial products. According to the most recent World Health Organization (WHO) estimates, asbestos-related diseases, resulting from exposure at workplace claims more than 107000 lives every year worldwide. The various types of toxic effects induced by asbestos in humans include - i) inflammation and fibrogenesis of lung, ii) mesothelioma iii) asbestosis and iv) bronchogenic carcinoma. The stability of asbestos in natural environment and its biological aggressiveness is related to their fibrous structure and dimensions. The actual risk associated with the exposure to nanosized asbestos, which is still unknown and escapes most regulations worldwide, has been shown in various toxicity assessment studies conducted on various animal models. In an effort to reduce the size of asbestos and therby its toxicity by limiting its biopersistence, oxalic acid treatment of asbestos coupled to power ultrasound treatment was carried out. The nanosized particles formed were still found to retain their hazardous effect. Similar were the results obtained on strong acid treatment of asbestos as well. A probable solution to the asbestos toxicity problem therefore envisaged was bioremediation. This involved the secretion of iron chelating molecules termed siderophores by microbes, which are of significance due to their ability to form very stable and soluble complexes with iron. Iron in asbestos composition is a major factor responsible for its carcinogenicity, removal or extraction of which would prove to be an effective answer to the worldwide problem. Siderophores are low molecular weight organic compounds with a very high and specific affinity to chelate iron and enhance their diffusion to the microbial cell surface. A number of successful experiments carried out in vitro have shown positive results concerning reduction in asbestos toxicity on chelation of iron by siderophores. The present investigation tends to put forth the aspect of these biomolecules secreted by specific bacteria and fungi as potent tools to fight the micro to nano sized asbestos fibre toxicity. [ABSTRACT FROM AUTHOR]

Glass ionomer cement (GIC) has limitation on the mechanical properties especially compressive strength. The change of compressive strength of GIC by adding oxalic acid and tartaric acid has been investigated. Oxalic acid and tartaric acid was added to the liquid components at concentrations of 0 - 15% (w/w). Powder component of GIC was made from optimum experimental powder glass SiO2-Al2O3-CaF2. GIC was characterized by compressive strength test, SEM-EDX and FTIR. The addition of tartaric acid to GIC has greater improvement than addition of oxalic acid. The addition of tartaric acid at 10 % (w/w) to GIC has greatest value of compressive strength. [ABSTRACT FROM AUTHOR]

As an attractive radionuclide for positron emission tomography, this study explores the extraction and reactivity of 45Ti produced via the 45Sc(p,n)45Ti reaction on a GE PETtrace. Using a small hydroxamate column, we have demonstrated an overall recovery of >50% of 45Ti in ∼1 mL of 1M oxalic acid. Conditions for reacting with desferal were also explored, with effective specific activities up to 38 GBq/μmol obtained. [ABSTRACT FROM AUTHOR]

The selective production of crystalline polymorphs is an outstanding problem in solid-state chemistry. In this study, the preparation of a new urea solid form is based on pure urea and oxalic acid (1:1), by grinding the components at room temperature. The resulted compound was investigated by X-ray powder diffraction (PXRD), thermal analysis (DSC, PPE) and infrared (FTIR) spectroscopy. The difference between the PXRD patterns of urea-oxalic acid and of the starting components evidenced a new compound. Using X-ray powder diffraction method, the lattice parameters were determined. Some thermal properties of the obtained compound were also investigated by the previous mentioned calorimetric techniques. [ABSTRACT FROM AUTHOR]

Recently, some studies show various organic compounds such as pesticides and dyes degraded with the irradiation of ultraviolet light and visible light in the presence of oxalic acid and ferric ion (ferrioxalate/UVvis process). The process has much advance than other technologies because it can utilize the wavelength of 300∼450nm and also under the condition of neutral pH. Chlorinated organic compounds such as trichloroethene (TCE), which have caused ground water pollution on a lot of sites, have never been applied by photodegradation with this process. In this study, we showed the degradation of TCE in the presence of oxalic acid and iron ion and the change of pH, ferric and ferrous ion concentration during the photodegradation of TCE with ferrioxalate/UV-vis process. TCE was degraded in the presence of oxalic acid and iron ion. In the reactions, the equilibrium of oxalate ion and iron ion is important since it determines the amount of ferrioxalate complex which absorbs light and induces the reactions of the degradation of TCE. Thus, the pH value and iron ion concentration are the important factors which determine the amount of ferrioxalate complex. The pH is nearly constant during the photodegradation of TCE. The ferrous ion concentration was decreased as soon as beginning photodegradation of TCE, and then the ferrous ion concentration and ferric ion concentration became constant. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

This study examines the electrochemical anodization of Ti foils in the presence of oxalic acid and malonic acid as field supporting agents. Notably, these additional electrolyte constituents are found to have a strong influence in the formation of TiO2 nanotubes. These nanotubes were also found to possess good crystallinity and better surface morphology. Interestingly, the TiO2 nanotubes grown showed hydrophobic behavior. [ABSTRACT FROM AUTHOR]

We have carried out Raman spectroscopic studies on α-oxalic acid dihydrate up to ~15 GPa. Our data analysis indicates the occurrence of a phase transition across 2.2 GPa. The softening of O-H stretching mode, associated with water molecule, implies the strengthening of the O-H---O hydrogen bond and possible formation of hydronium ion. [ABSTRACT FROM AUTHOR]