Equilibrium Journal of Chemical Engineering
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Study of the Effect of Dissolved Oxygen Concentration on Gold Recovery Leaching at PT Indo Muro Kencana
Get PDFGold is a very important metal in human life. Most gold is processed using the sodium cyanide (NaCN) leaching method. Maximizing the leaching recovery can be done by optimizing the leaching process parameters, one of which varies the concentration of dissolved oxygen (DO). Oxygen is added to oxidize gold atoms (Au) into cations (Au+) which will then react with cyanide ions (CN-) to form the aurocyanid complex anion Au(CN)2- dissolved in cyanide solution. This study aims to investigate the best method between the use of O2, H2O2, and Aachen reactor in generating dissolved oxygen concentration to oxidize valuable metals. From the experimental results, which method can produce higher leaching recovery will be seen. Based on this study, the dissolved oxygen variation derived from oxygen injection (O2) obtained a percent recovery of 92.5% Au and 80.5% Ag, hydrogen peroxide (H2O2) achieved a percent recovery of 92.5% Au and 79.9% Ag, and Aachen sheared (Aachen reactor) with a percent recovery of 95% Au and 81.9% Ag.Keywords:Gold, Leaching, Dissolved Oxygen, Percent Recovery, Aachen Reacto
Validation of Methylene Blue Analysis Method in Wastewater Samples by UV-Vis Spectrophotometry
Get PDFAbstract. Methylene blue (MB) is an extensively utilized cationic dye in the textile industry. MB is, however, a highly noxious substance that can have detrimental effects on both the environment and human health. MB can pollute waterways and cause the mortality of aquatic organisms in the environment. Due to the hazards posed by MB, it is crucial to have an effective method for analyzing its concentration in wastewater. This will ensure that MB-contaminated water is appropriately treated and disposed of, thereby protecting the environment and human health. One of the analyses utilized the Evolution 360 UV-Vis Spectrophotometer to determine methylene blue concentrations. The Evolution 360 UV-Vis Spectrophotometer method was validated by measuring linearity tests, limit detection and quantization, precision, and accuracy. The R-value for linearity measurements is greater than 0.99, indicating that the method is proportionally validated. As required, the precision measurement yields acceptable results, with a %RSD value of less than 2%, and the accuracy measurement yields a recovery of 100% (between 80 and 110%). So that the method for measuring the concentration of methylene blue in water using the UV-Vis Evolution 360 Spectrophotometer satisfies the requirements for linearity, precision, and accuracy.Keywords:Analysis, Methylene Blue, Method Validation, Spectrophotomete
The Use of Soxhlet Techniques in the Essential Oil Extraction from Anise Seeds (Pimpinella anisum)
Get PDFAbstract. Anise seeds can be processed into essential oils by steam distillation and solvent extraction. This research aims to produce a high oil yield by determining the optimum conditions of extraction, extracting anise seeds according to optimum conditions, producing anise oil with good quality based on 90% alcohol solubility analysis, analyzing the acid number, and conducting GC-MS analysis. The Activity Method was carried out by determining the optimum conditions of extraction on the effect of the variation in the ratio between anise seed powder and petroleum ether. Furthermore, based on optimal conditions, extraction was carried out at a temperature of 60°C, 5 hours with 5 repetitions. The results of essential oils were analyzed including solubility analysis, oil acid number, and GC-MS. The optimal extraction conditions were obtained at the ratio of anise seeds and petroleum ether 1:12.5 with an average oil yield of 4.72%. The results of the analysis showed that anise oil had good quality based on the oil solubility in 90% alcohol with a 1:7 ratio. The acid number of anise seed oil was obtained at 1.14444. GC-MS analysis showed that anise seed oil contained estragol, anethole, limonene, fenchone, and anis ketone.Keywords:Anise seeds, essential oil, soxhlet, GC-M
Effect of Potassium Peroxodisulphate and Microwave Power on Hydrogel Character Based on Banana Peel Waste Using Microwave Grafting Method
Get PDFABSTRACT. Musa paradisiaca var. raja peel waste contains cellulose which has the potential to be a raw material for synthesizing hydrogels. This research utilizes acrylamide monomer grafted onto banana peel cellulose backbone using the microwave grafting method to produce hydrogel. The banana peel waste was dried to a constant weight and then crushed into powder. Banana peel powder was through a delignification process with the addition of NaOH and bleached with NaClO to took only the cellulose of the banana peel. The mixture of banana peel cellulose-acrylamide-potassium peroxodisulfate powder through the grafting process was repeated with variations in KPS concentration and microwave power. The reaction was terminated with a hydroquinone solution, washed with acetone, and then precipitated. The precipitated solid was dried to a powder called cellulose-g-PAAM. A homogeneous solution of 2% carrageenan-cellulose-g-PAAM underwent a physical crosslinking process using KCl and CaCl2 solutions after passing through palm oil to form a bead gel. The purpose of this research was to determine the effect of potassium peroxodisulfate (KPS) initiator concentration and microwave power on the swelling capacity in water. The properties of obtained dried bead gels were characterized their functional groups using FTIR and swelling capacity test in water. From this research, it can be concluded that banana peel cellulose was successfully grafted onto acrylamide monomer as evidenced by the FTIR test results. The lower KPS concentration is the greater on the swelling capacity and the microwave power has no effect on the swelling capacity of bead gels.Keywords: Banana peel, Bead gel, Microwave, Swelling degree
The Impact of pH And Temperature on the Crystallization Process of Coconut Palm Sugar
No full textAbstract. This experiment concerns the optimization of coconut sugar production by using innovative processing methods. The raw material, coconut sap, is systematically collected through tapping coconut flowers to ensure consistency. Focusing on the process of coconut sap into coconut sugar in a convenient powdered form emphasizes a systematic approach. The research utilizes a controlled heating method with a crystallizer, introducing variations in pH and temperature. This research was to determine the best temperature and ph to produce coconut palm sugar products that comply with several SNI 3743: 2021 standards. To solve the problems associated with traditional palm sugar production emphasizes the need for innovative and efficient approaches. The results show that quality of palm sugar: sucrose content of 86.93%, moisture content of 1.03%, ash content of 1.65% and Pb content according to Indonesian Nasional Standard of palm sugar SNI 3743:2021. This systematic and innovative approach aligns coconut sugar with the quality standards specified in SNI 3743:2021, offering a high-quality and marketable formKeywords:Coconut Nira, Palm Sugar, Volume, p
The Conversion of Sorghum (Sorghum bicolor (L.) Moench) Stem Waste into Activated Carbon by the Pyrolysis Method Using ZnCl2 Activator
Get PDFAbstract. The use of activated carbon in Indonesia is expanding along with the increasing demand for activated carbon. Therefore, it is necessary to continue to search for raw materials and methods for producing activated carbon to produce high-quality activated carbon. Sorghum stalk (Sorghum bicolor (L.) Moench) is used as a new precursor for the formation of activated carbon by utilizing a ZnCl2 activator followed by pyrolysis in a furnace with a temperature of 800°C. This study aims to determine the effect of drying and the concentration of activator agents on activated carbon production. The ZnCl2 activator concentrations used were 15% and 30%. The results showed that the activated carbon obtained through the withdrawal process with a ZnCl2 concentration of 30% had the highest carbon content, namely 100%. Test results with FTIR spectroscopy showed that the activated carbon samples had groups (C-H), (O-H), (C≡C), (C=O), (C=C), and (C-O). In addition, the SEM test results showed that the surface of the activated carbon formed had many pores. With the presence of activated carbon from sorghum stem waste, it is hoped that this product can reduce the contaminants contained in wastewater.Keywords: Activation, Activated Carbon, Waste, Pyrolysis, Sorghum, ZnCl
Isotherm Adsorbsi Uap Air Komposit Poli(asam laktat) - Grafit
Get PDFABSTRAK. Poli asam laktat adalah polimer hidrofobik yang termasuk dalam kelas biomaterial yang bersifat biodegradable. Poli asam laktat berpotensi untuk dijadikan komposit polimer konduktif (conductive polymer composite - CPC) yang dipergunakan sebagai bahan semikonduktor dengan cara mencampurkan grafit kepadanya. Perilaku adsorpsi uap air perlu dipelajari untuk mengetahui stabilitas komposit dan ditunjukkan melalui kurva isotherm adsorpsi uap air. Tujuan dari penelitian ini adalah mempelajari isotherm adsorpsi uap air komposit poli asam laktat/grafit pada berbagai komposisi grafit. Pengamatan terhadap isotherm adsorpsi uap air dilakukan dengan metode gravimetri pada berbagai kondisi kelembaban relatif. Hasil yang diperoleh menunjukkan bahwa kurva isotherm mengikuti tipe II menurut kasifikasi Brunauer, yaitu kurva berbentuk sigmoidal. Semakin tinggi kondisi kelembaban relatif, semakin besar kandungan air kesetimbangan. Peningkatan kandungan air kesetimbangan secara tajam terjadi pada kondisi kelembaban di atas 75%. Semakin tinggi komposisi grafit, semakin besar kandungan uap air kesetimbangan. Data kesetimbangan dicocokkan dengan model kesetimbangan sorpsi uap air yaitu model Guggenhiem-Anderson-deBoer (GAB), model Peleg, dan model Oswin. Model GAB memberikan gambaran isotherm yang terbaik.Kata kunci: Adsorpsi Uap Air, Kesetimbangan, Komposit, Poli Asam Laktat/Grafit, Pemodelan ABSTRACT. Poly(lactic acid)/PLA is a hydrophobic polymer that belongs to the class of biodegradable biomaterial. PLA can be used as material in the manufacture of conductive polymer composite (CPC), which is used as a semiconductor material by mixing graphite into it. The water vapor adsorption behavior needs to be studied to determine the stability of the composite. This research aims to investigate the water vapor adsorption isotherm in poly(lactic acid)/graphite composites on various graphite compositions. The gravimetric method carried observations on the water vapor adsorption isotherm at various relative humidity conditions. The results obtained indicate that the isotherm curve follows type II according to the Brunauer classification. The higher the relative humidity, the greater the equilibrium water content. A sharp increase in the equilibrium water content occurs at humidity conditions above 75%. The higher the graphite composition, the greater the equilibrium moisture content. The Guggenhiem-Anderson-deBoer (GAB), Peleg, and Oswin sorption models were used to fit the experimental data. The GAB model best described the isotherms of the composites.Keywords: Composite, Equilibrium, Modeling, Poly(lactic acid)/Graphite, Water Vapor Adsorptio
Proses Pembuatan Biodiesel Dari Mikroalga Nannochloropsis sp. Menggunakan Metode Transesterifikasi In-Situ dengan Katalis KOH
Get PDFABSTRAK. Mikroalga Nannochlopsis sp merupakan alternatif bahan baku yang digunakan untuk pembuatan biodiesel karena memiliki kandungan asam lemak dan lipid yang tinggi serta pertumbuhannya yang begitu cepat. Metode yang digunakan yaitu transesterifikasi in situ dimana proses ekstraksi dan transesterifikasi berlangsung secara bersamaan yang terdiri dari 2 tahap, proses transestrifikasi in situ dan pemurnian biodiesel. Proses transeserifikasi in situ berlangsung selama 8 jam setelah itu, dilanjutkan dengan proses distilasi untuk menghilangkan kandungan n-heksana dan di oven selama 2 jam untuk menguapkan air yang tersisa. Penelitian ini memiliki tujuan yaitu untuk mengetahui pengaruh rasio molar minyak mikroalga : metanol dengan variasi katalis yang dimana rasio 1:6 memiliki tingkat kesetimbangan yang tinggi sehingga dapat menghasilkan %yield yang besar. Rasio molar minyak mikroalga : metanol 1:6 dengan variasi katalis KOH 2; 2,5; 3; 3,5; dan 4%w/w, dengan pelarut n-heksana 70%v/v terhadap yield crude dan kandungan FFA. Hasil yield crude biodiesel yang didapatkan pada penelitian ini sebesar 7%, kadar FFA sebesar 0,74 mg NaOH/gr.Kata kunci: Biodiesel, FFA, Nannochloropsis sp, Transesterifikasi In-Situ, Yield CrudeABSTRACT. Microalgae Nannochloropsis sp is an alternative raw material which is used for biodiesel production because it has a high content of fatty acids and increased lipid and its growth is so fast. The method was in situ transesterification in which extraction and transesterification processes took place simultaneously and consisted of 2 steps; in situ transesterification process and biodiesel purification. The in-situ transesterification process lasted for 8 hours after that, followed by a distillation process to remove the n-hexane content and in the oven for 2 hours to evaporate the remaining air. The aim of this study was to determine the effect of the molar ratio from microalgae oil: methanol with variations of catalyst where the ratio of 1:6 has a high equilibrium level so that it can produce a large % yield. the molar ratio from microalgae oil: methanol 1:6 with variations of KOH catalysts 2; 2.5; 3; 3.5; and 4%w/w, with solvent n-hexane is 70%v/v to the yield of crude and FFA biodiesel. The variable used was the molar ratio variation of microalgae oil: methanol 1:6. The yield of biodiesel crude obtained was 7%, and FFA content was 0.74 mg NaOH/gr.Keywords: Biodiesel, FFA, Nannochloropsis sp, Transesterification In-Situ, Yield Crud
Pembuatan Plastik Biodegradable Pati Jagung Terplastisasi Sorbitol dengan Pengisi Selulosa dari Ampas Tebu
Get PDFABSTRAK. Plastik menimbulkan kerusakan lingkungan karena sifatnya yang sulit terurai secara alami. Banyaknya ampas tebu di Indonesia dan tingginya kandungan selulosa dapat digunakan sebagai pengisi pada pembuatan bioplastik. Selulosa memberikan sifat kedap air, menghambat biodegradasai, dan meningkatkan kuat tarik bioplastik. Oleh karena itu dilakukan penelitian pembuatan bioplastik menggunakan ampas tebu sebagai pengisi. Pembuatan bioplastik menggunakan metode solution casting. Hasil terbaik pengujian daya serap air pada rasio pati:ampas tebu 7,5:2,5; massa sorbitol 2,3 gr; dan suhu 75oC dengan nilai 46,638%. Hasil terbaik pengujian biodegradasi pada rasio pati:ampas tebu 8,5:1,5; masssa sorbitol 2,7 gr; dan suhu 65oC dengan nilai 88,253%. Hasil terbaik pengujian kuat tarik dan perpanjangan putus dengan nilai 2.9574 N/mm2 dan 0.8896%. Hasil kedua pengujian masih belum memenuhi standar SNI 7828:2014.Kata kunci: Ampas Tebu, Bioplastik, dan Selulosa ABSTRACT. Plastic causes environmental pollution because it is difficult to decompose in nature. The large amount of bagasse in Indonesia and the high cellulose content can be used as filler for making bioplastics. Cellulose as a bioplastic filler provides water resistance, inhibits biodegradation, and increases tensile strength. Therefore, research was conducted using bagasse as a bioplastic filler. Bioplastics are made by the solution casting method. The best results of water absorption at the ratio of starch: bagasse 7.5:2.5; mass of sorbitol 2,3 g; and temperature of 75oC with a value of 46.638%. The best results of biodegradability at the ratio of starch: bagasse 8.5:1.5; mass of sorbitol 2,7 g; and temperature of 65oC with a value of 88.253%. The best results of tensile strength and elongation at break are 2.9574 N/mm2 and 0.8896%. The results of the both tests still do not meet the requirements of SNI 7818:2014 standard.Keywords: Bagasse, Bioplastic, and Cellulos
Synthesis of Syngas into Dimethyl Ether Using Cu-Zn-Al/-Alumina Bifunctional Catalyst as an Environmentally Friendly Fuel for Substituting Liquified Petroleum Gas
Get PDFAbstract. In order to meet the need for Liquified Petroleum Gas in Indonesia, which is currently around seventy percent of which is still imported, it is necessary to find a replacement. One of the efforts to replace the Liquified Petroleum Gas is by utilizing dimethyl ether which can be produced from coal as raw material. Coal can be catalytically converted to syngas and then syngas can be catalytically converted to dimethyl ether via a direct two-step or one-step route. This paper will discuss the one-step synthesis of dimethyl ether from syngas using Cu-Zn-Al/g-Alumina as a bifunctional catalyst. The syngas used consists of carbon monoxide and hydrogen with a mole ratio of 1:2. The conversion reaction was carried out in a fixed-bed reactor at the pressure of 40 bar, the temperature of 240-300 0C, and the space velocity of 29.3-32.7 mL/g catalyst/minute. The highest conversion of CO that can be achieved is 90.08 % at a temperature of 300 oC and the space velocity of 29.3 mL/g catalyst/minute. The synthesis product was analyzed using GC. The dimethyl ether is an environmentally friendly fuel and non-toxic compound that does not destroy ozone, does not contain sulfur, and has a calorific value of about 30.5 MJ/kg which is lower than 50.56 MJ/k