Jurnal Rekayasa Proses
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Tertiary butylhydroquinone influence over oxidation stability of biodiesel from waste cooking oil
Full text linkABSTRACTAn oxidation stability is very important for a long-term storage of biodiesel. Some physical (density and viscosity) and chemical properties (acid value, iodine value, and peroxide value) were analyzed to predict the oxidation stability for biodiesel produced from Waste Cooking Oil (WCO). WCO is one of the potential feedstocks in Indonesia, which is a large cooking oil consumer. Biodiesel from WCO was produced by transesterification process in 60 oC temperature for one hour reaction time. Methanol was added in 4:1 (v/v) ratio of WCO with 2% potassium hydroxide as a catalyst. This study observed the influence of tertiary butylhydroquinone (TBHQ), a synthetic antioxidant, on the oxidation stability of biodiesel. TBHQ was used as an antioxidant agent to prevent biodiesel oxidation for such long-term storage. It was blended with biodiesel at various concentrations (0-1200 ppm). Samples were taken every week to measure the density, viscosity, acid value, iodine value (IV) and peroxide value (PV) during the storage process of the biodiesel blends which was conducted for 4 weeks. The experimental results revealed that an improvement in oxidation stability was achieved in all TBHQ concentrations. All parameters meet Indonesia’s National Standards (SNI) for biodiesel added with TBHQ up to 1200 ppm. Biodiesel which was treated with 1200 ppm of TBHQ provided the best result, due to its density, viscosity, IV, and PV. However, TBHQ addition was did not affect the free fatty acid and acid number for 4 weeks of storage.Keywords: antioxidant; biodiesel; oxidation stability; waste cooking oilABSTRAKKetahanan oksidasi merupakan karakteristik yang sangat penting dalam penyimpanan biodiesel. Penelitian ini menganalisis sifat-sifat fisis (densitas dan viskositas) serta sifat-sifat kimia (angka asam, angka iod dan angka peroksida) biodiesel minyak jelantah untuk memperkirakan ketahanannya terhadap pengaruh oksidasi. Minyak jelantah merupakan salah satu bahan baku biodiesel yang sangat potensial di Indonesia, karena kapasitas penggunaannya yang cukup besar. Biodiesel minyak jelantah dihasilkan dengan transesterifikasi pada suhu 60 oC selama 1 jam. Metanol yang ditambahkan dalam reaksi ini menggunakan perbandingan volume 4:1, dengan katalis KOH sebanyak 2% berat minyak. Penelitian ini mempelajari pengaruh tertiary butylhydroquinone (TBHQ) terhadap ketahanan oksidasi biodiesel minyak jelantah. TBHQ digunakan sebagai antioksidan dalam penyimpanan biodiesel jangka panjang. TBHQ dicampurkan ke dalam biodiesel dengan variasi konsentrasi 0-1200 ppm. Ketahanan oksidasi dipelajari selama masa simpan 4 minggu. Sampel dianalisis densitas, viskositas, angka asam, angka iod dan angka peroksida setiap minggu. Hasil analisis menunjukkan bahwa ketahanan oksidasi biodiesel minyak jelantah telah memenuhi SNI pada semua konsentrasi TBHQ. Hasil terbaik diberikan oleh biodiesel jelantah yang ditambahkan 1200 ppm TBHQ, menilik dari nilai densitas, viskositas, angka peroksida dan bilangan iod. Penambahan TBHQ tidak berpengaruh secara signifikan terhadap nilai asam lemak bebas dan angka asam selama penyimpanan 4 minggu.Kata kunci: biodiesel, ketahanan oksidasi, antioksidan, minyak jelanta
Coconut husk to reducing sugar conversion using combined ultrasound and surfactant aided subcritical water
Full text linkThe first purpose of this study was to investigate the effect of operating variables and surfactant concentration in subcritical water to after ultrasonic process on the sugar-producing yield from coconut husk. The second purpose was to obtain the optimum operating condition of the subcritical water process. The sonication before the subcritical water process was done by dispersing 40 mesh coconut husk powder in water at 60°C, and 35 kHz. The effect of sonication time was studied by comparing the material crystallinity and composition after being treated for 30 minutes. In this research, the optimization was done by using a Box-Behnken response surface methodology (RSM) experimental design with 3 factors (temperature, time, and surfactant concentration). The designed lower and upper levels were 130°C and 170°C, 40, and 80 minutes, as well as 1 and 3% (w). The results showed that the quadratic response surface model predicted the maximum reducing sugar yield to be 12.0%, which was achieved at the optimum condition of 170°C, 77.5 minutes, and 2.3% SDS surfactant addition. The experiment run at the obtained optimum condition resulted in a reducing sugar yield of 11.7%, which was close to that obtained from the model prediction
Perbandingan jenis media imobilisasi terhadap kinerja proses peruraian anaerob termofilik palm oil mill effluent
Full text linkA B S T R A C TPalm oil mill effluent (POME) is wastewater with high organic matter, the raw material of biogas production through anaerobic digestion. In anaerobic digestion, the washout effect frequently becomes a problem, along with the increasing organic loading rate (OLR) in a continuous system. Therefore, the addition of immobilization media was carried out to reduce this risk. This study aims to evaluate the effect of immobilization media type and arrangement on the performance of thermophilic anaerobic digestion of POME. Two immobilization media were evaluated,i.e., carbon fiber textile (CFT) media and natural zeolite particles. The anaerobic process performance was determined by measuring the concentration of volatile fatty acids (VFAs), soluble chemical oxygen demand (sCOD), and methane (CH4) yield. This study indicated that the immobilization media led to higher CH4 yields than the reactor without immobilization media. The CH4 yield of the reactor with natural zeolite was 0.3487 L/g sCOD, 0.3050 L/g sCOD in the reactor with CFT media, and 0.2873 L/g sCOD in the reactor without immobilization media. In addition, only natural zeolite can maintain reactor performance when the temperature accidentally increased with a recovery period of 14 days.Keywords: anaerobic digestion; biogas; carbon fiber textile; natural zeolite; POME.ABSTRAKPalm oil mill effluent (POME) merupakan limbah cair dengan kandungan organik yang tinggi sebagai bahan baku produksi biogas melalui peruraian anaerob. Dalam peruraian anaerob, efek washout selalu menjadi masalah seiring dengan meningkatnya organic loading rate (OLR) pada sistem kontinu. Oleh karena itu, dilakukan penambahan media imobilisasi untuk mengurangi risiko tersebut. Penelitian ini bertujuan untuk mengevaluasi pengaruh jenis dan pengaturan media imobilisasi terhadap kinerja peruraian anaerob termofilik POME. Dua media imobilisasi yang diuji yaitu media jenis carbon fiber textile (CFT) dan media berupa partikel zeolit alam. Kinerja proses anaerob ditentukan dengan mengukur konsentrasi asam lemak volatil (VFA), soluble chemical oxygen demand (sCOD) dan yield metana (CH4). Hasil penelitian ini menunjukkan bahwa reaktor dengan media imobilisasi menghasilkan yield CH4 yang lebih tinggi dibandingkan dengan reaktor tanpa media imobilisasi. Yield CH4 reaktor dengan zeolit alam sebesar 0,3487 L/g sCOD, 0,3050 L/g sCOD pada reaktor dengan media CFT dan 0,2873 L/g sCOD pada reaktor tanpa media imobilisasi. Selain itu, hanya zeolit alam yang dapat mempertahankan performa reaktor saat mengalami gangguan peningkatan suhu secara tiba-tiba dengan masa recovery selama 14 hari. Kata kunci: biogas; carbon fiber textile; peruraian anaerobic; POME; zeolit alam
Sintesis polivinil alkohol tersulfonasi sebagai katalis dalam produksi metil ester: review
Full text linkA B S T R A C TSulfonated polyvinyl alcohol (PVA) can be used as a heterogeneous catalyst in esterification or transesterification reactions during methyl ester production. This catalyst with PVA support has the potential to be used commercially like Amberlyst 46. However, there are several drawbacks in the conventional methods to produce sulfonated PVA compared to Amberlyst 46. In this paper, various processes of sulfonated PVA synthesis will be discussed including the advantages and disadvantages compared to Amberlyst 46. The synthesis of sulfonated PVA catalysts can be carried out using sulfosuccinate acid reagents or other acid reagents that have sulfonic groups that act as the active sites of the catalysts. The use of sulfosuccinate acid as the reagent produces catalysts with better catalytic activity, but the resulting product is not in granule form like Amberlyst 46 and can only be used continuously for seven times. The use of chlorosulfonic acid as the reagent resulted in granular catalysts. However, the catalyst has less catalytic activity and stability, and the reagent has a relatively high environmental impact. For the synthesis performed using sulfuric acid as the reagent, no result regarding catalytic activity has been reported elsewhere. The blending of the catalyst with other polymers resulted in improvements in the thermal stability and mechanical strength of the sulfonated polyvinyl alcohol. After a careful review of the procedures, we propose blending or double cross-linking processes combined with sulfonated PVA synthesis as a promising method to increase the thermal stability and mechanical strength of the catalysts. However, it is necessary to perform further laboratory validations on the catalytic activity of the catalysts produced from the combined method because blending may reduce the acid capacity of the catalyst.Keywords: esterification catalyst, polyvinyl alcohol, sulfonation A B S T R A KPolivinil alkohol (PVA) tersulfonasi dapat digunakan sebagai katalis heterogen dalam reaksi esterifikasi atau transesterifikasi dalam produksi metil ester. Katalis dengan support polivinil alkohol ini berpotensi untuk digunakan secara komersial seperti Amberlyst 46. Akan tetapi, PVA tersulfonasi yang disintesis secara konvensional masih memiliki banyak kekurangan dibandingkan dengan Amberlyst 46. Pada kajian ini akan dibahas mengenai berbagai alternatif proses sintesis PVA tersulfonasi termasuk kelebihan dan kekurangannya jika dibandingkan dengan Amberlyst 46. Sintesis katalis PVA tersulfonasi dapat dilakukan menggunakan reagen asam sulfosuksinat (SSA) maupun reagen asam lainnya yang memiliki gugus sulfonat yang berperan sebagai situs aktif katalis. Penggunaan reagen SSA menghasilkan katalis dengan aktivitas katalitik yang baik namun produk yang dihasilkan tidak berbentuk granula seperti Amberlyst 46 dan hanya dapat digunakan ulang sebanyak tujuh kali. Penggunaan reagen asam klorosulfonat dapat menghasilkan katalis berbentuk granula, namun memiliki aktivitas katalitik dan kestabilan kurang baik, serta reagen yang digunakan cukup berbahaya. Untuk proses sintesis menggunakan reagen asam sulfat belum ada hasil mengenai aktivitas katalitik, tetapi dengan adanya blending dengan polimer lain dapat memperbaiki kestabilan termal dan kekuatan mekanik PVA tersulfonasi yang dihasilkan. Proses blending atau double cross-linking yang digabung dengan sintesis PVA tersulfonasi dapat meningkatkan kestabilan termal dan kekuatan mekanik sehingga metode gabungan ini diyakini sebagai metode yang paling potensial dilakukan untuk menghasilkan PVA tersulfonasi dengan karakteristik terbaik. Meskipun demikian, perlu dilakukan penelitian lebih lanjut disertai tahapan pengujian aktivitas katalitik pada katalis yang dihasilkan dari metode gabungan karena kemungkinan proses blending dapat mengurangi kapasitas asam pada katalis.Kata kunci: katalis esterifikasi; polivinil alkohol; sulfonas
Peruraian Anaerobik Termofilik Palm Oil Mill Effluent dengan Variasi Konsentrasi Substrat
Full text linkHigh utilization of palm oil in Indonesia corresponds to palm oil mill effluent (POME). The POME has chemical oxygen demand (COD) of up to 100.000 mg/L, which can pollute the ecosystem if not adequately treated. One of the methods to manage POME is anaerobic thermophilic digestion. The advantage of this method is the production of methane gas which is a form of alternative energy. Substrate concentration affects anaerobic digestion. This preliminary experiment aims to evaluate the performance of anaerobic thermophilic digestion on various POME concentrations at 55 °C. The anaerobic digestion was run with 16.000, 11.000 and 5.000 mg sCOD/L substrate concentrations. Digested cow manure (DCM) was used as inoculum. The process was running in a continuous system after 7-days of acclimatization of the batch system. The result shows that 16.000 and 11.000 mg sCOD/L concentrations produced more methane, but the methane yield was not statistically significant with the Tukey test (p=0,05). The POME with a 5.000 mg sCOD/L concentration produced less methane and plummeted after day 85. The lower methane production at lower substrate concentration was due to the low sCOD availability and high volatile fatty acid (VFA) accumulation which inhibited the methane production
Adsorption study of mango peel activated carbon as iron removal for batik waste industry
Full text linkA B S T R A C TMango peel waste which has a carbon functional group was converted to activated carbon. The as-synthesized activated carbon (AC) was then utilized as an adsorbent for batik waste which contains heavy metal substances such as Fe2+. The purpose of this study was to determine the optimum process variation in absorbing heavy metal ion Fe contained in batik waste. Four variation methods of activated carbon synthesis were explored to determine the most suitable method of AC synthesis. The results showed that the sample synthesized using a combination physical-chemical-physical process was the best process variation resulting in percentage removal of Fe2+ of 84.81%. FTIR showed that the functional groups in mango peel were visible for all variations of the process, namely hydroxyl (-OH) derived from cellulose and hemicellulose and carboxyl (-COOH) derived from pectin. The adsorption study showed that the most suitable isotherm for all process variations was Langmuir with an R2 value of 0.9999 for the MPAC-4 sample. The adsorption mechanism is physisorption with a value of E < 8 kJ/mol based on the D-R isotherm and has the largest adsorption capacity of Qmax 8.2 mg/g.Keywords: batik waste; adsorption; activated carbon; iron waste; mango peelABSTRAKLimbah kulit mangga yang memiliki gugus fungsi karbon dapat dikonversi menjadi karbon aktif. Karbon aktif hasil sintesis (AC) tersebut selanjutnya dimanfaatkan sebagai adsorben limbah batik yang mengandung zat logam berat seperti Fe2+. Tujuan dari penelitian ini adalah untuk mengetahui variasi proses optimum dalam menyerap ion logam berat Fe yang terkandung dalam limbah batik. Terdapat 4 variasi metode sintesis karbon aktif yang diteliti untuk menentukan metode sintesis AC yang paling cocok. Hasil penelitian menunjukkan bahwa sampel yang disintesis menggunakan kombinasi proses fisika-kimia-fisika merupakan variasi proses terbaik dengan persentase penyisihan Fe2+ sebesar 84,81%. Analisis FTIR menunjukkan bahwa gugus fungsi pada kulit mangga terlihat untuk semua variasi proses, yaitu hidroksil (-OH) yang berasal dari selulosa dan hemiselulosa dan karboksil (-COOH) yang berasal dari pektin. Studi adsorpsi menunjukkan bahwa isoterm yang paling cocok untuk semua variasi proses adalah Langmuir dengan nilai R2 = 0,9999 untuk sampel MPAC-4. Mekanisme adsorpsi adalah fisisorpsi dengan nilai E < 8 kJ/mol berdasarkan isoterm DR dan memiliki kapasitas adsorpsi terbesar Qmax 8,2 mg/g.Kata kunci: limbah batik; adsorpsi; karbon aktif; limbah besi; kulit mangg
Study of chromium removal from wastewater using SSF-CW model: comparison between physical adsorption by coal CFA and phytoremediation by vetiver grass (Vetiveria Zizanioides L)
Full text linkThe study aims to compare the effectiveness of chromium removal from water using adsorption by coal fly ash (CFA) and phytoremediation by vetiver grass (Vetiveria zizanioides L) as well as a combination of both CFA and vetiver grass. The experiment was carried out in four different reactors, having size of 100 cm (length) x 60 cm (wide) x 80 cm (height). One reactor was filled with gravel and CFA, without vetiver grass (RI), while another one was filled with gravel and vetiver grass, without CFA (RIV). The other two reactors were filled with gravel, CFA, and vetiver grass with the mass ratio of gravel/CFA of (25:2) and (25:1), denoted as RII and RIII, respectively. Fifty (50) L of synthetic wastewater containing 14.612 ppm of chromium was filled into the reactors and continuously recirculated for 15 days. Chromium accumulation in CFA and plants was analyzed on day 15. The results of plant development are indicated by the presence of new shoots and roots that grow during phytoremediation processes. In addition, there was an increase in weight and number of vetiver stems indicating the persistency of vetiver grass in such a harsh wastewater condition. The removal of Cr from wastewater in RI, RII, RIII and RIV at days 15 were 81%, 93.2%, 85.8% and 75.7%, respectively. It can be concluded that: (1) vetiver grass (Vetiveria zizanioides L) has high potential as phytoremediator plant, (2) Chromium adsorption by CFA plays important role in Cr removal from wastewater, and (3) combination of adsorption by CFA and a phytoremediation by vetiver grass significantly increases the removal of chromium from wastewater
Microwave assisted extraction of anthocyanin from purple sweet potato (Ipomoea batatas L.) using deep eutectic solvent (DES) based on citric acid
Full text linkPurple sweet potato (Ipomoea batatas L.) is one of the tubers or roots that is widely grown in Indonesia that contain high antioxidants. One type of flavonoid that functions as an antioxidant is a natural dye called anthocyanin. In the process of extraction of anthocyanin, the solvent has an important role. In this research, the deep eutectic solvent was used because it is more economical and environmentally friendly. This research will optimize the microwave assisted extraction of anthocyanin content in purple sweet potato (Ipomoea batatas L.) using a deep eutectic solvent with the variation of material to solvent ratio, microwave power, and extraction time. Optimization is done by using the statistical method Response Surface Method (RSM) with Total Anthocyanin content as a response. The optimum operating conditions for the extraction of anthocyanins from purple sweet potato using the deep eutectic solvent were obtained at a solid to solvent ratio of 1:29 at a microwave power of 270 watts for 193 s, with an optimum TAC value of 311.64 mg/L and an antioxidant value of 44.85%. The use of DES can increase the extraction yield and is environmentally friendly
Optimization of sustainable biodiesel production from waste cooking oil using heterogeneous alkali catalyst
Full text linkThe increasing world population, rapid industrialization, urbanization, and economic growth have led to a continuous increase in the consumption of fossil fuels to meet the ever-increasing demand for energy. Continuous emissions from burning fossil fuels will create a need to find appropriate and sustainable substitutes for fossil fuels. Biodiesel is the right alternative solution for diesel engines because it is renewable, non-toxic, and environmentally friendly. Waste cooking oil (WCO) from the food, non-food, restaurant, and household sectors is produced on a large scale in every country and can contribute to environmental pollution if proper disposal systems are not applied. Instead of throwing it landfills Environmental pollution can be minimized by recycling WCO. This study evaluates the potential of using WCO to produce biodiesel using zeolite synthesized from fly ash as a heterogeneous alkali catalyst through a transesterification reaction. The reactor in this study used a 1,000 ml three-necked boiling flask equipped with a condenser, cooling tank, and pump. Stirring and heating during the process of biodiesel production using a magnetic stirrer and a hot plate. The thermometer is used to measure the reaction temperature. Optimization of biodiesel production from zeolite catalyst synthesized from fly ash based on variations in the ratio of methanol: oil (8:1; 10:1; 12:1; and 14:1), catalyst weight (1, 2, 3, and 4% weight), and temperature (45 oC, 55 oC, and 65oC). Zeolite from fly ash produces biodiesel with a yield of 91.67% with optimum operating conditions reaction time of 60 minutes, methanol oil ratio of 8:1, operating temperature 55oC, and the amount of catalyst 1% by weight. This experiment confirms the possibility of utilizing fly ash waste for the application of catalysts in biodiesel production
In-Situ Catalytic Pyrolysis of Spirulina platensis residue (SPR): Effect of Temperature and Amount of C12-4 Catalyst on Product Yield
Full text linkCurrently, dependence on fossil energy, especially petroleum, is still high at 96% of the total consumption. One solution to overcome fossil energy consumption is processing alternative energy sources derived from microalgae biomass. This study aims to study the pyrolysis of microalgae with the addition of the C12-4 (Cr2O3+Fe2O3+C+CuO+promoter) catalyst. The biomass used in this study was Spirulina platensis residue (SPR). This study used a fixed bed reactor with an outer diameter of 44 mm, an inner diameter of 40 mm, and a total reactor height of 600 mm. The C12-4 was mixed fifty grams of SPR with a particle size of 100 mesh with a ratio variation of 5, 10, and 15 wt.%. The feed mixture was placed in the reactor (in-situ), and the reactor was tightly closed. The nickel-wire heater wrapped around the reactor wall was employed. The pyrolysis heating rate was 24.33 °C/min on average, and the temperatures were varied as 300, 400, 500, 550, and 600 °C. The research found that the optimum temperature conditions without and with the catalyst to produce bio-oil were different. The pyrolysis without any catalyst (500 ⁰C), with a catalyst of 5 wt.% (500 ⁰C), 10 wt.% (400 ⁰C), and 15 wt.% (550 ⁰C) produced the bio-oil yield of 15.00, 17.92, 16.78 and 16.54, respectively. The use of 5, 10, and 15 wt.% catalysts increased the water phase yield. The char yield was influenced by the amount of catalyst only at 300 ⁰C; i.e., the more catalysts, the less char yield. The pyrolysis without any catalysts produced the highest gas product. A catalyst significantly increased the pyrolysis conversion from 48.69 (without catalyst) to 62.46% (15. wt.% catalyst) at a temperature of 300 ⁰C. The optimum conditions for producing the best bio-oil were at 600 °C and 10 wt.% of catalysts, which resulted in an O/C ratio of 0.14.Keywords: C12-4 catalyst, in-situ catalytic pyrolysis, Spirulina platensis residue, yield bio-oilA B S T R A KKetergantungan terhadap energi fosil khususnya minyak bumi, saat ini masih tinggi yaitu mencapai 96% dari total konsumsi. Salah satu solusi untuk mengatasi ketergantungan energi fosil adalah dengan mengolah sumber energi yang berasal dari biomassa mikroalga. Penelitian ini bertujuan untuk pirolisis mikroalga dengan penambahan katalis C12-4 (Cr2O3 + Fe2O3 + C + CuO + promotor). Sampel yang digunakan adalah residu Spirulina platensis (SPR). Penelitian ini menggunakan reaktor unggun tetap dengan diameter luar 44 mm, diameter dalam 40 mm, dan tinggi reaktor 600 mm. Spirulina platensis dengan ukuran partikel 100 mesh sebanyak 50 gram dicampur dengan katalis C12-4 dengan variasi 5, 10, dan 15 wt.%. Campuran umpan (in-situ) dimasukkan ke dalam reaktor dan ditutup rapat. Pemanas menggunakan arus listrik melalui kawat nikel yang dililitkan pada dinding reaktor. Laju pemanasan pirolisis rata-rata 24,33 °C/menit, variasi suhu 300, 400, 500, 550, dan 600 °C. Kondisi optimum tanpa dan dengan katalis untuk menghasilkan bio-oil memiliki nilai yang berbeda yaitu pirolisis tanpa katalis (500 ⁰C), dengan katalis 5 wt.% (500 ⁰C), 10 wt.% (400 ⁰C) dan 15 wt.% (550 ⁰C) menghasilkan bio-oil 15,00; 17,92; 16,78; dan 16,54. Penggunaan katalis 5, 10, dan 15 wt.% berat dapat meningkatkan fasa air hasil. Yield char dipengaruhi oleh jumlah katalis hanya pada 300 ⁰C, semakin banyak katalis maka yield char semakin menurun. Pirolisis tanpa katalis menghasilkan produk gas tertinggi. Penggunaan katalis sangat signifikan dalam meningkatkan konversi pirolisis dari 48,69 (tanpa katalis) menjadi 62,46% (katalis 15 wt.%) pada suhu 300 ⁰C. Kondisi optimum untuk menghasilkan minyak nabati terbaik adalah pada 600 °C dengan katalis 10% berat, menghasilkan rasio O/C sebesar 0,14.Kata kunci: C12-4 catalyst, in-situ catalytic pyrolysis, Spirulina platensis residue, yield bio-oi