Advances in Science and Technology Vol. 138

Abstract: Textile dyes waste can cause a big problem for the environment. Adsorption is a simple approach in treatment of textile dyes waste. On the other hand, the use of disposable adsorbents also creates production cost problems because they are less economic. Currently, research on adsorbents is forwarded to the use of biopolymers such as chitosan, chitin, and cellulose. This research studied the use of cellulose beads, made from cellulose acetate (CA) blended with polyethylene glycol 200 (PEG200), as adsorbent in removing cationic dye of methylene blue (MB). Adsorption performance of cellulose beads was evaluated and optimized under variation of adsorption conditions (pH, beads dose, dye concentration) and PEG200 content. Optimization was carried out by using response surface methodology (RSM) with a face-centered central composite design (FCCD) model. The results showed that the optimum condition was obtained at pH of 7, beads dose of 2 g/L, dye concentration of 20 mg/L for bead composition of CA/PEG200 (90/10). The optimum % dye removal predicted by the design model was 52.4706 %.

Abstract: Palm oil mill effluent (POME) is one of the main problems generated by the palm oil industry in the form of high solids, oils and grease, as well as very high biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS). Electrocoagulation (EC) is an electrochemical process that destabilizes the charge of a pollutant using an electric current through an electrode and traps the pollutant in the floc so that it can be separated from the mixture. The main purpose of this study is to investigate the removal of BOD, COD, and TSS from POME using EC process. POME was obtained from the outlet pond of PT. X which is located in Jorong District, South Kalimantan with very high BOD, COD, and TSS content. The EC process uses a series of modified electrocoagulation devices, 3 mm aluminum plate, and Riden RD6012W Digital DC. The optimization of the EC process includes parameters for different currents density (2, 4, 6, 8, and 10 mA cm^-2), and reaction time (30, 60, 90, 120, 150, 180, 210, 240, 270 min). While other parameters that are considered constant are aluminum electrode, inter-electrode distance 3 mm, temperature and pH. The results showed that the highest % removal of BOD and COD occurred at currents density of 4 and 6 mA/cm² with a time of 270 minutes of 99% and 78% respectively. While the TSS is 93% at currents density of 6 mA cm^-2 and 270 minutes.

Abstract: Natural gas has diverse content such as Methane, Ethane, Carbon dioxide, Hydrogen Sulfide, and other gases. In addition, natural gas is formed over a very long time, where it comes from fossil fuels. Natural gas that has been treated and produced products are called synthesis gas which can be used to make ammonia (NH₃). To produce ammonia, steam compounds (H₂O) are used which are reacted with natural gas to produce hydrogen (H₂) and Nitrogen (N₂) obtained from the air. Ammonia manufacturing can be done by several processes, namely desulfurization (natural gas purification), Steam Reforming, Shift Converter, CO₂ removal, methanation, and refrigeration units. The data used in this simulation is data on the ammonia plant at PT. Petrokimia Gresik. What is seen from this simulation is the influence of the composition of natural gas with variations in composition, namely 75% – 99% methane. The largest yield was obtained in the composition of 75% methane with an ammonia product yield of 82.34 tons/hour, this is because the division of the composition is divided propositionally into other compounds such as ethane, and propane, i-butane, etc. which have more H₂ content. Then there is the ratio of methane flow rate to steam using a variation of 1:3.5 - 1:7.5 where the largest ammonia product is obtained from a ratio of 1:7.5 with ammonia product yields of 84.79 tons/hour because more and more steam causes the formation of more hydrogen. Furthermore, there is a ratio of methane flow rate to air with a variation of 1:5.5 - 1:7.5 where the largest ammonia product is obtained from a ratio of 1:5.5 with an ammonia product yield of 84.87 tons/hour because the air content consists of N₂ and O₂, where if the O₂ content is a lot it will react with Methane so that the H₂ produced will be less if methane reacts also with O₂ not only with H₂O.

Abstract: The phenomena of global warming caused by excessive greenhouse gas emissions, particularly carbon dioxide gas, has seriously impacted many significant areas of human life. Over the last 30 years, the oil and gas sector has caused a gradual increased in terms of its carbon dioxide gas emission by a large portion. This research aims to conduct a conceptual study of techno-economic to compare heat pump-assisted distillation technologies against the conventional distillation method. This research has the objective of significantly reducing the utility consumption demand in the form of heating load and electrical power requirement, as well as minimizing the emission of carbon dioxide gas generated from gas turbine generator and steam boiler units. This research consists of a base case model that implements the conventional distillation method for the condensate stabilization process, while both optimized 1 and 2 implement heat pump-assisted distillation technologies, in the form of mechanical vapor recompression (in optimized model 1) and heat integrated distillation (in optimized model 2). All simulation models were prepared using process simulation software ASPEN HYSYS at steady state conditions with Peng-Robinson as a fluid package. The economic analysis conducted was based on a minimum feasibility estimate of class V with an accuracy of -30% / +50%. Optimized models 1 and 2 were able to reduce the total duty requirement by 23.68 % and 26.70 % compared to the base case model, thus causing a reduction in the OPEX by 51.11 % and 24.23 %. In line with the reduction of total duty requirement, the carbon dioxide gas emission rate for optimized models 1 and 2 has also decreased by 22.78 % and 36.18 % compared to the base case model. Furthermore, despite the slight increase in CAPEX, optimized models 1 and 2 still shows a positive trend in terms of their economic valuation, with a reduction in TAC compared to the base case model by 14.88 % and 4.86 % respectively.

Abstract: Plants need two types of nutrients, which are macronutrients and micronutrients. Micronutrient needed by plants in small concentration (≤ 100 ppm) i.e. Cu and Zn. This study aims to determine the best composition ratio of Cu:EDTA, Zn:EDTA, and Cu:Zn:EDTA for making the micronutrients, determine the effect of Cu and Zn on lettuce (Lactuca sativa L), and determine the most effective type of micronutrient fertilizer and its concentration for lettuce growth. It was started by dissolving materials with 200 ml distilled water, then stirred and heated at 70-80°C for two hours. After that, the solution was precipitated for two days at room temperature. Methanol was added only before precipitating CuZn-EDTA. The precipitate or micronutrient crystals of Cu-EDTA, Zn-EDTA, and CuZn-EDTA were then filtered and dried in a desiccator for three days. Each of micronutrient crystal was dissolved into 25 ml water then the lettuce will be sprayed with micronutrient solution for two and three sprays once a week. Observations related to the quantity of leaves, plant length, and leaf width were carried out for 25 days and then plant harvested and weighed. The result shows that the best compotition ratio for making micronutrients were Cu:EDTA (1:1.85)w/w; Zn:EDTA (1:3.43)w/w; and Cu:Zn:EDTA (1:1.6:3.85)w/w/w. Concentration of micronutrient solution applied were 5000 and 1000 ppm. Respectively for each concentration, micronutrient CuZn-EDTA affected the leaves quantity growth with the slope of 0.0655 and 0.0642; and yields (g/cm2) with the slope of 0.495 and 0.46. Zn-EDTA had an effect on plant length growth with a slope of 0.1525 and 0.091; and leaf width growth with a slope of 0.0216 and 0.0111. Cu and Zn contained in lettuce leaves then analyzed and was known for Cu-EDTA, Cu and Zn contained (mg/kg) respectively were 37.78 and 50.68; for Zn-EDTA were 32.8 and 61.25; for CuZn-EDTA were 33.23 and 48.16 (mg/kg). The metal content analyzed in lettuce leaves is not suitable for consumption because it exceeds the maximum limit written on the Decree of the Directorate General of POM No 03725/B/SK/VII/89. Application of fertilizer should be more diluted to less than the maximum limit.