Abstract. Recently, Na2/3[Fe1/2Mn1/2]O2 has received attention as a potential candidate material for cathode sodium-ion batteries. However, this material was synthesized by a solid-state process, resulting in larger particle size and nonuniform morphology. The larger particle size will sluggish the Na ion diffusion. Here we report the synthesis of Na2/3[Fe1/2Mn1/2]O2 using a simple sol-gel process. The X-ray diffraction revealed that the sample was identified as Na2/3[Fe1/2Mn1/2]O2 with a hexagonal crystal structure. However, the impurities are formed at diffraction angles of 36.28°, 45.03°, and 51.23°. Calcination temperature affects the formation of the crystal phase, grain growth, morphology, and particle size. Our findings provide valuable insight into the development of Na2/3[Fe1/2Mn1/2]O2 material with desirable properties. Keywords: Sol-Gel, Solid State, Grain Growth, Calcination, Na2/3[Fe1/2Mn1/2]O2
Gas sweetening is a process to remove CO2 and H2S from natural gas. The current established technology is by using Amine contactor where the solvent used is in form of Amine solution. To simulate the effect of different solvent, electrolyte-NRTL is used to model the equilibrium, and mass transfer-kinetic is used to model the rate-based processes. This modeling approach is rather complex and available only in commercial and proprietary process simulation software. Therefore we propose an alternative modeling approach where we use extended NRTL and stage efficiency to model the acid gas absorption processes. We find that this approach is quite good to describe CO2 absorption, yet unsuccessful to calculate the H2S absorption. Inadequate vapor liquid equilibrium parameter regression for H2S, specifically at low partial pressure might cause the problem. However the stage efficiency approach shows good result where it is comparable to rate-based model and corresponds to current understanding of physico-chemical phenomenon of acid gas absorption.
Waste from coal-burning power stations and other sectors that rely on coal as a source of energy is one of the environmental issues. Fly ash obtained from burning coal causes pollution in the surrounding environment. Subsequently, a great deal of study was conducted on the application of flying ash coal. Among the techniques for making use of the flying ash of coal is the extraction of silica. This study carried out silica leaching using Aqua Regia (a combination of HCl and HNO₃) with various ratios of 1:1, 1:3, and 3:1. The leaching process was carried out at varying temperatures of 30, 45, 60, 75, and 90 °C, with a leaching time of 1 and 2 hours. Precipitates containing silica were analyzed for their levels using XRF. The results of the study show that the ratio HCl:HNO₃ 3:1 is able to extract more silica than other solvent ratios. Keywords: Silica, Fly Ash, Leaching, HCl, HNO₃
Abstract. The making of glucose syrup from purple sweet potatoes is motivated by the high demand for alternative sugar in Indonesia. Through the processes that have been carried out and the results of previous studies, the potential of purple sweet potatoes to be processed into glucose syrup has been produced. This experiment was conducted to determine whether purple sweet potatoes can be processed into glucose syrup and to determine the suitability of the product to the standard. To convert purple sweet potatoes into glucose syrup, it is necessary to first extract the starch content in purple sweet potatoes and go through the process of making glucose syrup by the acid hydrolysis method using citric acid of various concentrations (0.2, 0.4, 0.6, 1 N). For the feasibility of consuming glucose syrup from purple sweet potatoes, a toxicity test was carried out using the Brine Shrimp Lethality Test (BSLT) method. Tests were also carried out on water, ash, reducing sugar, and starch content to then be compared with the Indonesian glucose syrup standard (SNI 01-2978-1992). The results showed that the reducing sugar content of purple sweet potato glucose syrup followed the glucose syrup quality standard, which was 43.31%, the lowest water content was 18.35%, the lowest ash content was 7.95% and there was no starch content in purple sweet potato liquid sugar. The aroma of the glucose syrup produced was following the Indonesian National Standard, but the color and taste produced were not yet in accordance. The toxicity test of purple sweet potato liquid sugar showed a lethal concentration value of LC50 >1,000 ppm, which means that purple sweet potato liquid sugar has no toxic potential so it is safe for consumption. Keywords: Purple Sweet Potatoes, Liquid Sugar, Acid Hydrolysis
Liquid organic fertilizer is organic fertilizer in liquid form which is partly or wholly derived from organic compounds such as plant, animal and industrial residues, in solid or liquid form. The nutrients contained in it are in the form of a very fine solution so that it is easily absorbed by plants, even the leaves or stems. Organic fertilizer is one solution to restore soil minerals physically, chemically and biologically from the bad effects of synthetic fertilizers. Liquid fertilizer is obtained from a solid fermentation process first, then followed by a liquid anaerobic fermentation and extraction process. In the fermentation process, the role of microbes greatly determines the product produced. Tofu liquid waste is made from cooking residue from cooked soybeans boiled and the water from the remaining tofu tends to be thrown into the surrounding environment. Waste Liquid tofu contains organic ingredients, namely carbohydrates reaching 20-50%, protein 40-60%, and 10% fat. It is known that this tofu waste can be used as liquid organic fertilizer by fermentation. Tofu liquid waste contains organic substances, namely carbohydrates, proteins and fats, which can be used as liquid organic fertilizer. These substances must first be broken down into simpler elements by a fermentation process so that they can be absorbed by plants. Effective Microorganisms-4 as inoculants to increase microbial diversity in soil and can control unpleasant odors, accelerate the decomposition process, maximize the decomposition process, increase nutrient content, reduce the growth of pathogenic microorganisms, improve the physical, chemical and biological structure of the soil and bioremediation. Keywords: Liquid Organic Fertilizer, Liquid Waste, Fermentation, Effective Microorganisms-4, Nutrient
