Absorpsi Gas Karbondioksid Dengan Larutan Soda Api Dalam Kolom Unggun Tetap

Absorption is one of mass transfer processes to separate a specific gas from its mixture using suitable absorbent. Absorption of CO2 from its mixture is usually done using Na OH, MEA or K2CO3 solution. In this research, a gas mixture contains CO2 was contacted with NaOH solution as absorbent in a fixed bed column. This research also studied the effect of NaOH solution flow rates at the range of 0.026 to 0.042 L/s to the absorption rates. On the other hand, operating pressure, gas flow rates, type and packing size, and CO2 initial concentration were maintained at constant value. Physico - chemical analysis was developed as a mathematics model to determine combined gas-liquid mass transfer coefficient at gas side (Kga) and reaction rate constant All coefficients were determined for absorption column design data which are accurate and suitable to be applied in industry. Experimental research result shows that determined gas-liquid mass transfer coefficient (Kga) of CO2 - NaOH absorption system were affected by liquid flow rates. The higher value of Na OH solution flow rates gave higher value of Kga. The Kga was in the range of I.1775.10-\u27 to 3.4748.10-\u27 (I/second) at liquid flow rate 0.026 - 0.042 L/s.. The calculated reaction rate constant was at constant value 1.002 x 104 -(mL/masecond). The volumetric gas-liquid mass transfer coefficients at gas side found from the experiments can be written in term of Sherwood and Reynolds number as follows: S,, = 4.0777 Re1-4°03 . S, "3 , with average relative error of 1.5391 %. The equation is valid for Reynolds number at the range of 13.2347 to 21.3789. Key words : Absorption, Kga, reaction rate constan

DEVELOPMENT OF EFFICIENT CALCIUM OXALATE REMOVAL TECHNIQUES FROM TARO CORMS

Taros  (Colocusiu  and  Xanthosoma  spp.) are tropical root crops commonly referred to as cocoyams, which have been used as subsistence staple foods in many parts of the tropics and sub-tropics in Africa and Australasia. Proximate analysis of the taro corms has shown that it contains digestible starch, protein of good quality, vitamin C, thiamin, riboflavin and niacin. However, one major limiting factor in the utilization of taros is the presence of oxalates which impart acrid taste or cause irritation when foods prepared from them are eaten. Ingestion of foods containing oxalates has also been reported to cause caustic effects, irritation to the intestinal tract and absorptive poisoning as well as disrupting the bio-availability of calcium. While several methods have been made to reduce oxalate content in taro corms, none has been reported to meet the satisfactory level of the consumers. Considering that calcium oxalate content in the skin is higher than in the tuber flesh and that physical (thermal and irradiation) degradation of calcium oxalate is more pronounced than chemical and biological degradations, a method to reduce the calcium oxalate content in the taro corms is proposed. The proposed method involves peeling, washing, steeping, boiling and drying, which is expected to remove about 93.14% of the original calcium oxalate content. Keywords: taro; calcium oxalate; removal; developmen

Inhibitory Effects of Cyanide on the Activity of Granular Starch Hydrolyzing Enzyme (GSHE) during Hydrolysis of Cassava (Manihot Esculenta Crantz) Starch

The kinetics and inhibitory effects of cyanide on the granular starch hydrolyzing enzyme (GSHE) activity during hydrolysis of cassava (Manihot esculenta Crantz) starch at low temperature were studied. The substrates included native cassava starch at various concentrations (100-400 g/L) and native cassava starches with added cyanide at various concentrations (50-150 mg/kg), while the concentration of enzyme was 1.5% (w/w). A decrease in reducing sugar concentration during hydrolysis of cassava starch indicated that the cyanide reduced the enzyme activity. Lineweaver-Burk plot of Michaelis-Menten equation was used to study the inhibition kinetics. The maximum velocity (Vmax) value was higher for native cassava starch than that of native cassava starch with added cyanides. The presence of cyanide was found to reduce the Vmax values. No significant different of the saturation constant (Km) value between native cassava starch and native cassava starch with added cyanides was observed. Based on the inhibition type analysis, the effect of cyanide in the cassava starch can be classified as a noncompetitive inhibition, with the Ki value of 0.33 mg/L

Produksi Mikroalga Berbiomasa Tinggi dalam Bioreaktor Open

In 2025, it has been estimated that due to lack of fossil oil as the main energy sources will significantly affect to Indonesia’s energy crisis. Therefore, the attemps to search new alternative of energy source are highly importantl. The biodiesel from current sources (Jatropha, palm oil, and soy) are not yet able to cover all the needs if the fossil oil can not be explored anymore. In this research, the use of microalgae was proposed as the new potential of energy (biodiesel) sources. The current problem of large scale cultivation is low yield of biomass due to no optimality in the bioreactor design and operation. This research aims to design an efficient bioreactor, cheap and able to produce high cell density algae culture. For this purpose, an open pond type of bioreactor was selected and by facilitating Computational Fluid Dynamic (CFD) the hydrodynamic properties of this bioreactor can be evaluated. The evaluations were perfomed for length (L) and width (W) ratio, power consumption, and dead zones in the bioreactor under turbulent flow simulation. The resukt showed that L/W ratio more than 10 is optimal for open pond bioreactor. Moreover, this resercah also showed that at Rembang and Jepara coasts, we can isolated the strain which have high potential for biodiesel sources (oil content:20-30%) Keywords: Microalgae, Chlorella, CFD, Open pon

Reaction and Mass Transfer Kinetics Model of Hydrogen Peroxide Oxidation of Starch under Influence of Ultraviolet Irradiation

The coupled hydrogen peroxide/ultraviolet irradiation (H2O2/UV) process as one of environmentally friendly advanced oxidation processes (AOPs) has been successfully applied in the oxidation of corn starch. The aim of this work was to develop a simplified model for the describing of reaction kinetics and mass transfer phenomena of starch oxidation using hydrogen peroxide under influence of UV irradiation. The model development involved the elementary chemical and photochemical reactions as well as pseudo-steady state mass transfer of hydroxyl radicals from bulk liquid to the surface of starch particles. Effects of initial H2O2 concentration and pH were investigated. The results show that H2O2/UV starch oxidation follows the first order reaction with respect to H2O2 and starch concentrations. The proposed model satisfactorily describes the H2O2/UV starch oxidation phenomena, where very good agreement with experimental data was obtained. Hydroxyl radical’s mass transfer from bulk liquid to the surface of starch particles was found to be the rate controlling step for coupled H2O2/UV starch oxidation

Waste Cooking Oil Utilisation as Bio-plasticiser through Epoxidation using Inorganic Acids as Homogeneous Catalysts

This paper exposed the preparation of epoxidised waste cooking oil with sulfuric acid, nitric acid, and hydrochloric acid in order to utilise waste cooking oil economically efficient due to highly unsaturated triglycerides. These triglycerides act as potential raw material due to double bond content. The double bond content can be converted as bio-plasticiser. The paper aimed to investigate optimum conversion with different inorganic acids based on oxirane conversion and iodine value at different time. Epoxidation reaction was carried out in the conventional acetic acid-hydrogen peroxide process. The result showed that sulfuric acid can obtain higher conversion than that of other acid catalysts. It resulted with 20 % of oxirane conversion for 5 h

Kinetics of Starch Degradation during Extrusion Cooking of Steady State Flow Konjac (Amorphophallus oncophyllus) Tuber Flour in a Single Screw Extruder

The presence of glucomannan in Konjac (Amorphophallus oncophyllus) tuber flour has promoted its various applications, especially in the food, drink, drug delivery and cosmetics. Starch is the main impurity of Konjac tuber flour. Although the common wet refining method may result in a high purity Konjac tuber flour, it is very tedious, time consuming and costly. This research aimed to study the kinetics of starch degradation in the extrusion cooking process of dry refining method to produce high quality Konjac tuber flour. In this research, Konjac tuber flour with 20% (w/w) moisture was extruded in a single screw extruder by varying screw speeds (50, 75, 100, 125, 150 and 175 rpm) and barrel temperatures (353, 373, 393, 413 and 433 K). The results showed that the starch extrusion cooking obeys the first reaction order. The reaction rate constant could be satisfactorily fitted by Arrhenius correlation with total activation energy of 6191 J.mol−1 and pre-exponential factor of 2.8728×10−1 s−1. Accordingly, thermal degradation was found to be the primary cause of starch degradation, which shared more than 99% of the energy used for starch degradation. Based on mass Biot number and Thiele modulus evaluations, chemical reaction was the controlling mechanism of the process. The results of this research offer potential application in Konjac tuber flour refining process to obtain high quality flour product. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

PENENTUAN JENIS SOLVEN DAN PH OPTIMUM PADA ANALISIS SENYAWA DELPHINIDIN DALAM KELOPAK BUNGA ROSELA DENGAN METODE SPEKTROFOTOMETRI UV-VIS

Rosela merupakan tanaman yang telah diketahui banyak mengandung senyawa antosianin sebagai antioksidan. Antioksidan merupakan senyawa penting dalam menjaga kesehatan tubuh karena berfungsi sebagai penangkap radikal bebas yang banyak terbentuk dalam tubuh. Antosianin pada kelopak bunga rosela berada dalam bentuk glukosida yang salah satunya adalah senyawa delphinidin. Kandungan senyawa delphinidin yang terkandung dalam kelopak bunga rosela dapat dianalisis kadarnya menggunakan metode Spektrofotometri UV-Vis. Prinsip dasar Spektrofotometri UV-Vis adalah analisis yang didasarkan pada pengukuran serapan sinar monokromatis oleh suatu laju larutan berwarna pada panjang gelombang spesifik dengan menggunakan monokromator prisma atau kisi difraksi dengan detektor fototube. Kelarutan dari delphinidin antara lain larut dalam akuades, metanol dan etanol pada berbagai suhu berkisar antara (298 sampai 343) K di bawah tekanan atmosfer. Tujuan dari penelitian ini adalah untuk mengetahui jenis solven yang paling sesuai sebagai pelarut delphinidin dan pH yang paling optimum. Pada penelitian ini digunakan variabel tetap yaitu bunga rosela dan suhu percobaan : 30oC. Sedangkan variabel berubahnya yaitu jenis solven (akuades, metanol, dan etanol) serta pH dengan variasi pH 4; 4,5; 5; 5,5; 6. Hasil percobaan, menunjukkan bahwa metanol merupakan solven yang paling sesuai untuk melarutkan senyawa delphinidin, sedangkan pH yang paling optimum untuk analisis senyawa delphinidin dengan metode Spektrofotometri UV-Vis adalah 4,5

Functional and thermal properties of flour obtained from submerged fermentation of durian (Durio zibethinus Murr.) Seed chips using Lactobacillus plantarum

Durian (Durio zibethinus Murr.) is one of the most popular seasonal fruits in South East Asia, mainly Thailand, Indonesia, Malaysia and the Philippines. After consuming of the fruit pulp, the abundant durian seeds are usually disposed. However, they can be eaten after being boiled, roasted, baked, fried or cooked. Unfortunately, there is no sufficient information on the innovative utilizations of the durian seeds as raw materials in the preparation of modern foods. This study aims to characterize the functional and thermal properties of native and fermented durian seed flour obtained from submerged fermentation of durian seed chips using Lactobacillus plantarum, so that this information can be used as the basis in the development of functional foods. The effect of solid consistency (5 - 25% w/v), inoculum size (2.5 - 15% w/v) and time (0 - 40 h) on the swelling power, water solubility, water absorption capacity, oil absorption capacity, carbonyl and carboxyl content, degree of substitution and gelatinization temperature of the flour were investigated. Fermentation was found to alter all of the functional and thermal properties of durian seed flour. Although fermentation increased the gelatinization temperature and oil absorption capacity of durian seed flour, their value were still lower than that of wheat flour. Based on the carboxyl group content and degree of substitution, the fermented durian seed flour obtained from fermentation of durian seed chips at 15% w/v solid consistency and 5% v/v inoculums size for 24 h is safe for consumption. Fermented durian seed flour exhibits similar functional properties to that of wheat flour and offers its superiority and high potential applications in the food industry over wheat flour due to its high fiber content (8.50 &plusmn;0.26%), but low fat content (0.63 &plusmn;0.03%). However, rigorous research should be conducted to ensure the acceptability and practical implementation of fermented durian seed flour as raw material for the manufacture of bread, cookies, cake and noodle.</div

Response Surface Methodology for Formulating PVA/Starch/Lignin Biodegradable Plastic

The use of petroleum-based plastics has raised environmental issues as more plastic waste enters and accumulates in the environment. It has led to the development of biodegradable plastics. Starch is one of the potential materials to make biodegradable plastic, but starch-based plastic has poor mechanical strength. Blending starch with poly(vinyl alcohol) (PVA) and lignin is expected to improve the mechanical properties of the plastic. Biodegradable plastic films from PVA/starch/lignin blends with glycerol as a plasticizer were prepared using an internal mixer for compounding and a hot press molding machine for film making. The percentage of lignin (2-10%), glycerol (25-65%), and mixing temperature (190-230 oC) were varied according to the three levels of the Box-Behnken design. The ANOVA evaluation revealed that glycerol had the most significant effect on the mechanical properties of the film. Then, three models for the estimation of tensile strength, elongation at break, and tear resistance were developed. As expected, the models satisfactorily predict the effect of all input variables on the response variables. The optimum conditions for preparing the film were acquired from the equations, namely 197.6 oC for the temperature, 10% for lignin, and 45.1% for glycerol. The biodegradable plastic prepared using the optimum conditions possessed a tensile strength of 8.46 ± 1.08 MPa, an elongation at break of 139.00 ± 8.59%, and a tear resistance of 69.50 ± 2.50 N/mm. These values are in good agreement with the predicted values. Doi: 10.28991/ESJ-2022-06-02-03 Full Text: PD