ISSN / EISSN : 08520798 / 24075973
Current Publisher: Diponegoro University (10.14710)
Total articles ≅ 350
Latest articles in this journal
Reaktor, Volume 18, pp 209-215; doi:10.14710/reaktor.18.04.209-215
Abstract:Wastewater reclamation and reuse have become an alternative to saving operational costs while reducing the impact of waste pollution. In this paper, integration of electrocoagulation (EC) and polysulfone-based ultrafiltration (UF-PSf) membranes were used for the mentioned purpose. The EC unit equipped with 7 (seven) pieces of E-shaped of Al electrodes, which operated at a current of 3 (three) Amperes and a residence time of 2 (two) hours. The waste samples obtained from textile and oil palm industries. The experimental results were compared based on product quality and economic feasibility. When used for textile waste treatment, the integrated EC-UF units reduced TDS, TSS, BOD, and COD by 77%, 95%, 70 -80%, and 60-70%, respectively. While in palm oil waste treatment, the TDS and TSS reduced by 92% and 98%. The electrode loss rate in palm oil waste treatment was 2 (two) times greater than textile waste. By assuming that the waste production capacity of both industries was 400 m3/day, the water production cost in textile waste treatment was Rp. 4,000/m3. While in the palm oil waste treatment, the water production cost was Rp. 6,000/m3. These results showed that the EC-UF unit could be used as an economical and environmentally friendly alternative process for reclamation of industrial wastewater that meets the clean water quality standards.
Reaktor, Volume 18, pp 183-193; doi:10.14710/reaktor.18.04.183-193
Abstract:Peanut shells could be regarded as biomass wastes generated from agricultural products, which are abundantly available. The current handling of those wastes is merely through direct incineration, without a proper and controlled manner. Consequently, it could arouse environmental concerns, such as air pollution and human respiratory diseases. One alternative solution is converting those peanut shells to bio-pellet, expectedly applicable for fuels. Relevantly, research on bio-pellet manufacture from peanut shells, previously treated with the torrefaction, was conducted. It’s aimed mainly to identify the fuel-related characteristics of bio-pellet products. The tested bio-pellet parameters covered, moisture content, ash content, volatile matters, fixed carbon content, calorific values, and density. The results revealed that torrefaction temperature and time at raw materials (peanut shells) could improve their qualities in regard to particular calorific value compared to those before such torrefaction; which referred to Indonesia’s Standard (SNI-8021-2014) for wood bio-pellet. Further, torrefaction could increase bio-pellet quality which satisfied the SNI’s Standard, except for ash content. Optimal torrefaction treatment was obtained at 300oC temperature for 60 minutes, whereby it achieved remarkable bio-pellet characteristics in terms of moisture content (3.092%), ash content (6.116%), volatile matters (38.387%), fixed carbon (55.447%), calorific value (6174 cal/g), and density (0.703 g/cm3). The torrefaction bio-pellets from peanut shells could achieve remarkable performances, with respect to fuel consumption rate (0.68 kg/hr), heating value (6174 kcal/kg), and thermal efficiency (16.67%).
Reaktor, Volume 18, pp 194-201; doi:10.14710/reaktor.18.04.194-201
Abstract:To be used as organic fertilizer, compost must be stable and mature enough to ensure that it is safe for agricultural application. The stability and maturity of compost can be viewed from physical, chemical, and biological parameters. One of the biological parameters is the static respiration index (SRI). In many places, the SRI is applied as a representative indicator of the stability and maturity of compost but not in Indonesia compost standard of the SNI 19-7030-2004. This study aims to assess the index of the static respiration of composts and analyze their stability and maturity. The assessment was carried out on 10 compost samples sold in Jakarta and Depok. It is observed that 8 of 10 tested composts was stable and mature, with a static respiration index of 0.61–1.35 mg O2 g-1 VS h-1. One of the 10 composts was very stable and very mature, with a static respiration index of 0.46 mg O2 g-1 VS h-1 and 1 compost was unstable and immature, with an index of 1.79 mg O2 g-1 VS h-1. The results indicated that re-composted for seven days was adequate to make the compost more stable and mature than the initial state. Since maturity is not described by a single property, it is great assurance for the compost producer and end user in Indonesia that not only physical and chemical characteristics are used as indicator for compost stability and maturity but also biological indicator such as SRI. Keywords: compost; maturity; stability; static respiration index
Reaktor, Volume 18, pp 224-234; doi:10.14710/reaktor.18.04.224-234
Abstract:Starch of lesser yam (‘gembili’ in Indonesian) has been used as a base for edible film and coating. Potassium sorbate and cinnamon oil are known as strong antimicrobial agents. This research was aimed to investigate the physical and mechanical characteristics of edible film from lesser yam starch-plasticizer formulations added with potassium (K) sorbate or cinnamon oil and its application as coating to strawberries. Incorporation of either K-sorbate or cinnamon oil at higher concentration resulted in reduced tensile strength and elongation with higher water vapor transmission rate (WVTR). The selected edible film formulations were applied as coating on strawberry stored at two conditions: room (28-30°C) and refrigeration temperature (5-6°C). At room temperature, controls had shelf life only for 2 and 4 days and strawberries coated with addition of K-sorbate lasted for 5-6 days, and those with addition of cinnamon oil prolonged for 5-11 days. At refrigeration storage, shelf life of controls was 9 and 18 days whereas K-sorbate-added formulations further prolonged shelf life of strawberries for 19-21 days, and those added with cinnamon oil lasted for 25-26 days. Therefore, all coated, stored strawberries had longer shelf life and more retained strawberries’ quality including lower weight loss, higher hardness, and lower microbial count.
Reaktor, Volume 18, pp 177-182; doi:10.14710/reaktor.18.04.177-182
Abstract:This research was conducted to calculate the mass transfer coefficient value for ozonation reaction of κ-carrageenan solution in the bubble column reactor. Ozone gas was produced using ozone generator type corona discharge. In this study, operating conditions were regulated at ozone gas flow rate 2- 5 L min-1, pH 4-10, and temperature 29 ± 1 oC. Samples were tested every 5 minutes to determine the dissolved ozone concentration. The results showed that dissolved ozone concentrations increased with increasing ozonation time and ozone gas flow rate. However, a very high gas flow rate can increase turbulence so that the mass transfer coefficient (kLa) value decreased. In alkaline conditions, the formation of free radicals (HO*) increases so that the amount of dissolved ozone decreases. The kLa value of ozone gas in κ-carrageenan solution is slightly lower than the kLa value of the ozone gas in the water. The results of this study indicate that (kLa) ozone gas in water is 0.131 / minute while the value (kLa) in κ-carrageenan solution is 0.128 / minute.
Reaktor, Volume 18, pp 216-223; doi:10.14710/reaktor.18.04.216-223
Abstract:In small and medium industries, cassava starch is dried using conventional method by drying it directly under the sun. However, the main drawback of conventional method is low drying rate. Therefore, in this study, cassava starch with a water content of 40% (wet basis) was dried using a pneumatic dryer to a moisture content below 13% (wet basis). The aim of this research is to analyze the influence of drying air temperature, drying air flow rate and rate of feeding in relation to drying rate and energy analysis. Energy analysis was performed to determine the performance of pneumatic dryer. The energy analysis itself is done in the form of energy utilization and energy efficiency. The energy analysis shows that the increase of dryer temperature from 60 to 100oC will increase the utilization of energy from 0.34 to 0.76 J/s, while the energy efficiencies ranged between 30-40%. Proximate analysis shows that the dried cassava starch has an ash content of 0,24, grain fiber of 0,12, and degree of whiteness of 98%, which fulfills the SNI standard of cassava starch.
Reaktor, Volume 18, pp 235-240; doi:10.14710/reaktor.18.04.235-240
Abstract:Kaffir lime peels contain polyphenols as natural antioxidant and antimicrobial agent. The aims of this study were to (1) extract phenolics compounds from kaffir lime peels using water, ethanol 70% and ethanol 96% as the solvent, and (2) assess the antibacterial activity of the extract against Streptococcus mutans which is the main cause of dental caries. Research methodology includes preparation and extraction of polyphenols from kaffir lime peels, preparation of mouthwash based-kaffir lime peels extracts and evaluation the mouthwash ability to inhibit the growth of Streptococcus mutans. The results show water exhibited the best solvent to extract polyphenols among the three solvents. The total phenolics content in the water extract was observed at 11.42±0.48 mg GAE/g, whilst in the two ethanolic extracts were 10.91±0.87 and 8.87±0.53 mg GAE/g for ethanol 70 and 96%, respectively. Consequently, the water-based extract performed the highest antimicrobial activity. The highest inhibition zone was demonstrated by 100% extract of concentration extract variation. Although the inhibition zone of the mouthwash was smaller than the commercial product, the extract has the potential to be developed as a safe mouthwash for long-term usage.
Reaktor, Volume 18, pp 202-208; doi:10.14710/reaktor.18.04.202-208
Abstract:In Indonesia, a lot of discarded agricultural waste still contains cellulose (35-50%), the waste can still be hydrolyzed to glucose and then used as raw material in the manufacture of surfactants. Glucose can be reacted with tert-butanol using a para-toluene sulfonic acid catalyst to form tert-butyl glycoside surfactant. The purpose of this study was to study the process conditions influence the variable mole ratio, temperature, and catalyst percent on the yield of tert-butyl glycosides. The results showed that at mole ratio 1:5; temperature 70oC; and the percentage of catalyst 2.5 %, the yield obtained was 98.58 % with tert-butyl glycosides content of 61.2 %. Furthermore, the molecular structure of the surfactant was analyzed using FTIR while surface tension to determine the hydrophilic-lipophilic balance (HLB) value and obtained an HLB value of 4.61 Therefore, tert-butyl glycoside surfactant can be used as an emulsifier in the water-in-oil emulsion system.
Reaktor, Volume 18, pp 97-101; doi:10.14710/reaktor.18.2.97-101
Abstract:Cirebon Port has spacious work and water area that provides opportunities to be developed in industrial sectors, particularly the petrochemical industries such as ethylene and Liquefied Natural Gas (LNG). In atmospheric condition, they are classified as volatile gas. Either in processing or transporting, they are stored in closed system. However, they still have a probability to be released to the environment and may lead to a fire or explosion. This probability is increased in the existence of coal stockpile in the port area which can evoke a fire. Therefore, a safety study is needed to identify the risk of the loading-unloading activities. The problem was solved by following steps. First, the data such as physical properties, layout area, and geographical condition around the port were collected. Then, the hazardous nodes were identified qualitatively, and then the quantitative analysis was done using As Low As Reasonably Practicable (ALARP) analysis. From the safety study, a suitable handling and safety system is provided to ensure safety viability in the ethylene and LNG loading-unloading process at the Cirebon port.Keywords: ethylene; hazard assessment; LNG; loading-unloading process; Quantitative Risk Assessment (QRA)