Engineering Headway Vol. 6

Abstract: Recycling garbage with the pyrolysis technique to make liquid smoke is one effort to utilize biomass waste. Because it includes acetic acid and phenol, which aid in food preservation, liquid smoke can be used on foods. The goal of this research was to look into the usage of zeolite catalysts in the production of liquid smoke from various types of biomass via catalytic pyrolysis. Coconut shells, corn cobs, and rice husks are used as biomass. The investigation began with the activation of the zeolite catalyst, with the goal of cleansing the catalyst of impurities and boosting its activity by opening the pores. The catalytic pyrolysis process was then carried out at 350°C for 2 hours while adjusting the quantity of catalyst addition (4%, 5%, and 6%). Catalytic pyrolysis liquid smoke is collected and evaluated. As a preservative, studied liquid smoke is applied to skipjack tuna. Based on the quality of commercial liquid smoke, the results showed that coconut shell liquid smoke with a percentage of 6% zeolite added was the most optimal liquid smoke. 6.5% yield, yellowish brown hue, slightly pungent aroma, pH value 2, density 1.132 g/ml, acid content 24%, and viscosity 1.3090 cP were the features of 6% zeolite coconut shell liquid smoke.

Abstract: The Dual-Chamber Microbial Fuel Cell system has been successfully developed to produce bioelectricity based on tofu liquid waste. In this study, variations of the operating parameters of the MFC were carried out, namely differences in electrolyte solutions of potassium permanganate (KMnO₄) and potassium dichromate (K₂Cr₂O₇). In addition, the configuration of the reactor circuit used is a series reactor circuit and a single reactor. The results of the MFC process show that the maximum electric voltage and current strength values obtained in the KMnO₄ electrolyte solution are 880 mV and 0.352 mA, respectively. Meanwhile, the maximum electric voltage and current strength in the K₂Cr₂O₇ electrolyte solution are 569 mV and 0.228 mA. Furthermore, the use of potassium permanganate is known to produce a maximum power density of 20.88 mW/cm², which is two times greater than the maximum power density value produced by potassium dichromate, which is 8.73 mW/cm². Whereas the difference in the reactor series shows that the series reactor circuit can increase the maximum power density value of 356.61 mW/cm², higher than the single reactor which is 26.21 mW/cm². Based on all the data generated from this study, tofu liquid waste has the potential as the main ingredient in the MFC process to produce bioelectricity.

Abstract: Recent studies indicate that bio-oil production from EFB is highly influenced by the temperature during pyrolysis. In this study the pyrolysis process was conducted at the optimum temperature of 500°C for 60 minutes and the nitrogen gas flowrate (N₂) was varied between 1 and 3 L/min. The bio-oil itself can be obtained from the condensed gas pyrolysis product. The characteristics of bio-oil were then identified based on biofuel quality standards. The bio-oil was then tested in order to determine its physical properties such as its density, water content, and acid number. Besides, the chemical components of the bio oil were identified by using GC-MS. The results show that the density of bio-oil is within the range of 0.9918 - 1.0083 g/cm³. The highest water content produced is 27.22% at a flow rate of 1 L/min. The acid number of bio oil is ranging from 124.9 – 139.6 mg KOH / g. According to GCMS test results, linoleic acid content is high at a flow rate of 1 L / min, while hexadecane content dominates by 15.79% at a 2 L / min rate. Further observation on the rate of 3 L / min shows that phenol content increases.

Abstract: Silver (Ag) is one of the heavy metal wastes in the silver industry. Silver metal (Ag) contamination has an impact on human health and the environment so that a metal waste treatment method is needed to minimize the impact. This study used coffee grounds as an adsorbent for silver metal (Ag). The purpose of this study was to determine the characteristics of the adsorbent functional groups, adsorption time stability, optimum adsorbent mass, type of adsorption isotherm, and adsorption free energy (ΔGoAds). Activated carbon was prepared through three processes, namely baking at 110 oC for 2 hours, carbonization at 400 oC for 3 hours, and activation with 1 M H₃PO₄ for 24 hours. The characterization of the adsorbent was carried out using Fourier Transform Infrared Spectroscopy (FTIR). The results of the adsorbent characterization indicated the presence of functional groups, namely, C-H(Csp3), aromatic C=C, -CH3, and P=O from the remaining H₃PO₄ activator which experienced a shift in absorption as the adsorbent was treated. The results of this study showed that the stability of Ag adsorption time was 60 minutes and the optimum adsorbent mass was 1 gram. Adsorption isotherm type of metal Ag is Freudlich isotherm with linear equation y = 0.9084x + 0.6272 and R2 value of 0.9219. Isotherm Freudlich provides information on the n value of 1.1008 and KF of 4.238 L/mg. Calculation of adsorption free energy (ΔGoAds) obtained a value of-12.395 kJ/mol so that the adsorption process occurs physically.

Abstract: Silica based catalyst was prepared from geothermal sludge – solid waste from geothermal exploration - of Dieng Power Station, Central Java, Indonesia. The catalyst was prepared by extracting silica compound from the sludge matrix, followed by sulfonation to obtain sulfonated – solid catalyst. Catalyst sample analysis informed the catalyst was generally amorphous in structures, possessed surface area between 76 – 81 m²/g, with acidity approximately 5-6 mmol/g. Evaluation on catalyst activity was performed by applying it on sago starch hydrolysis - atmospheric pressure and 100 – 150°C (373 – 423 K) - in which more than 90 % conversion could be achieved.

Abstract: The world's energy needs to be enhanced after the COVID-19 pandemic has caused a shortage of petroleum-based fuels that has occurred in almost all countries in the world. It is essential to use non-edible vegetable oil as a renewable energy source. This study aimed to produce Schleichera Oleosa oil as biodiesel using a homogeneous catalyst (KOH). This study uses the ester/transesterification method in which Schleichera oleosa oil (SO) is heated in a 1L double jacket reactor at 60 °C. The results showed that the optimum conditions were obtained at 0.75 vol% KOH and an agitation speed of 1000 rpm with a reaction time of 90 minutes. This condition resulted in a biodiesel yield of 89%. Furthermore, it was found that the high oxidation stability was 9.03 h, and the pour point was 9 °C. Thus, the physicochemical biodiesel produced is acceptable according to the ASTM 6751 standard.

Abstract: The manufacture of bioplastic from potato starch (Solanum tuberosum L.) and glycerol from waste cooking oil with the addition of TiO₂ has been done by varying the concentration of TiO₂. This study aims to study the effect of the addition of TiO₂ on the physical and mechanical properties of potato starch and glycerol from leech oil. The research was conducted by making glycerol from waste cooking oil, making bioplastic film with various concentrations of TiO₂ (0; 1; 2; 3 and 4%), characterization of bioplastic, which includes physical and mechanical properties. The addition of TiO₂ as a bioplastic filler can affect its physical and mechanical properties. The result showed that each addition of 1% TiO₂ increased the thickness by 22,966 microns, the tensile strength value by 0.0853 N/mm², the average Young’s modulus by 0.0599 MPa, and decreased elongation by 5.0987%. The best bioplastic mechanical test results were produced at a starch composition of 2.5 grams and 2% (w/w) of TiO₂ particles.

Abstract: Plant diseases are taken into consideration as one of the major factors affecting food production and minimizing losses in production, and plant diseases must have rapid detection and recognition. Tomato (Lycopersicon esculentum) is one of the foodstuffs that are rich in nutrition and nutrients. Tomatoes are widely consumed by many countries including Indonesia and are hunted to be created in various spices, so tomatoes have a role in the economy due to the large demand. The recent enlargement of device studying techniques has found its application in plant disease detection especially tomato plants, presenting a powerful tool with relatively accurate effects. In this study, we present a systematic literature review aimed at identifying disease images in tomato plants. In this regard, we review 16 studies selected in the last five years with different approaches to address aspects related to tomato plant disease detection.

Abstract: Peptones are protein hydrolysis products consisting of a mixture of free amino acids, oligopeptides, and other fragmented protein components easily digestible by microorganisms. This study aimed to investigate the effect of crude ficin enzyme on the characteristics of peptones derived from yellowfin tuna (Thunnus albacares) dark meat and their potential application in microbial growth. Crude ficin enzyme concentrations used to produce peptones from yellowfin tuna dark meat were 0%, 0.1%, 0.2%, 0.3%, and 0.4%. The results showed that using crude ficin enzyme impacted the characteristics of peptones from yellowfin tuna dark meat, including protein content, amino nitrogen, degree of hydrolysis, and optical density. The research findings revealed protein content of 16.20%-32.51%, amino nitrogen of 2.74%-6.53%, hydrolysis degree of 28.37%-39.16%, and optical density value of 0.342-0.574. The optimal concentration of crude ficin enzyme, based on the results obtained in this study, 0.2% crude ficin enzyme was used for producing peptone from yellowfin tuna (Thunnus albacares) dark meat. .