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Penyusunan formula minyak lumas selalu melibatkan pencampuran base oil dan aditif melaluitahapan estimasi dan formulasi skala laboratorium, dilanjutkan dengan produksi skala komersial.Parameter kunci dalam penyusunan formula adalah viskositas kinematik yang nilainya dapatdihitung secara teoretis dan pengujian laboratorium. Beberapa metode estimasi viskositas campuranyang dikenal antara lain persamaan Refutas, metode Wright, dan metode yang dikembangkandan digunakan dalam American Society for Testing and Material (ASTM D 7152).Penelitian ini dilakukan untuk mempelajari akurasi ketiga metode tersebut dalam memprediksiviskositas kinematik campuran biner base oil dan aditif. Sampel campuran biner tersusun daridua jenis base oil mineral produksi PT Pertamina (Persero) dan aditif viscosity modifiers (VMs)produksi Lubrizol yang divariasikan pada kisaran konsentrasi 5-30 % berat. Nilai viskositaskinematik diukur pada temperatur uji 40 dan 100oC menggunakan cannon automatic viscometerseries 2000 (CAV 2000) dengan mengacu pada metode uji ASTM D 445. Evaluasi data dilakukanuntuk mendapatkan nilai persen average absolute deviation (%AAD) sebagai indikator akurasihasil estimasi dari setiap metode dibandingkan dengan data empiris.Hasil penelitian menunjukkan bahwa nilai %AAD pada 24 data uji dari 12 sampel campuranbiner dan temperatur uji 40oC adalah 10,56 %, lebih rendah dibandingkan persamaan Refutas danmetode ASTM, yaitu 41,19 dan 41,25 %. Pada temperatur uji 100oC nilai %AAD metode Wrightadalah 15,03 %, lebih rendah daripada persamaan Refutas dan metode ASTM yaitu 39,15 dan39,43 %. Berdasarkan hasil tersebut, dapat disimpulkan bahwa metode Wright memberikan nilaiestimasi yang lebih akurat dibandingkan dengan persamaan Refutas maupun metode ASTM.

This study aims to develop mathematical equations used in Wright’s method to predictkinematic viscosity of liquid-binary mixture consisting of base oil and additive. The equationis developed by addition of specific constants (αi and αc), representing interaction ofeach component in the mixtures. Evaluation is done using 70 empirical data from 35 samplesderived from liquid blending of 4 types of base oils (B.1, B.2, B.3 and B.4) and olefincopolymers (OCPs), varied in the range of 5-30 % of weight. Kinematic viscosity is measuredat 40oC and 100oC using a cannon automatic viscometer series 2000 (CAV 2000)according to ASTM method D 445. Validation of the equation (Developed-Wright’s method)is performed over all of liquid-binary mixtures of base oil-OCPs, and the accuracy isindicated by percent average absolute deviation (%AAD). The results show that the additionof specific constants could minimize the deviations of estimated values. The averagedeviation of Developed-Wright’s method on kinematic viscosity estimation at 40oC and100oC becomes 2.056 % and 1.917% respectively, lower than Wright’s method which are8.341 % and 14.696%; meanwhile the maximum deviation reaches 5.821 % and 4.657%,lower than Wright’s method which are 21.256 % and 25.265% respectively. These valuesindicate that the Developed-Wright’s method has better accuracy.

Sektor pertanian global kini menemui tantangan. Pupuk nitrogen diproduksi dengan proses Haber-Bosch mengonsumsi 1-2% total produksi energi dunia dan menghasilkan polutan CO 2 300 juta ton/tahun serta menyumbang 2,5% gas rumah kaca setiap tahunnya. Selain itu, pandemi COVID-19 menyebabkan disrupsi supply chain industri pupuk, mengakibatkan harga pupuk global meningkat. Teknologi elektrolisis plasma merupakan green technology murah dalam memproduksi pupuk nitrat cair dari udara, menggunakan spesies reaktif radikal OH. Penelitian bertujuan untuk memproduksi pupuk nitrat cair melalui elektrolisis plasma dengan pengaruh daya dan laju alir udara. Pengujian kinerja pupuk dilakukan pada tanaman cabai, tomat, dan sawi. Metode ini dilakukan pada reaktor batch menggunakan variasi laju alir udara 0,2; 0,4; 0,6; 0,8; 1 lpm, daya 500; 600; 700 watt, dan konsentrasi pupuk nitrat yang diujikan 100, 200, dan 300 ppm. Hasil menunjukkan semakin besar daya, dan laju alir udara meningkatkan produksi nitrat. Penelitian menghasilkan nitrat terbesar saat menggunakan larutan elektrolit 0.01 M K 2 SO 4 dengan 0.01 M K 2 HPO 4 , daya 600 watt dan laju alir udara 0,8 lpm. Pemberian pupuk nitrat cair menunjukkan hasil lebih baik dibandingkan tanpa pupuk maupun dengan pupuk komersial. Tanaman cabai menunjukkan persentasi peningkatan tertinggi. Dosis optimum setiap tanamannya adalah cabai 100 ppm, tomat 200 ppm, dan sawi hijau 200 ppm.

The Gas Gathering Station (GGS) in field X processes gas from 16 (sixteen) wells before being sent as selling gas to consumers. The sixteen wells have decreased in good pressure since 2011, thus affecting the performance of the Acid Gas Removal Unit (AGRU). The GGS consists of 4 (four) main units, namely the Manifold Production/ Test, the Separation Unit, the Acid Gas Removal Unit (AGRU), the Dehydration Unit (DHU). The AGRU facility in field X is designed to reduce the acid gas content of CO2 by 21 mol% with a feed gas capacity of 85 MMSCFD. A decrease in reservoir pressure caused an increase in the feed gas temperature and an increase in the water content of the well. Based on the reconstruction of the design conditions into the simulation model, the amine composition consisting of MDEA 0.3618 and MEA 0.088 wt fraction to obtain the percentage of CO2 in the 5% mol sales gas. The increase in feed gas temperature up to 146 F caused foaming due to condensation of heavy hydrocarbon fraction, so it was necessary to modify it by adding a chiller to cool the feed gas to become 60 F. Based on the simulation, the flow rate of gas entering AGRU could reach 83.7 MMSCFD. There was an increase in gas production of 38.1 MMSCFD and condensate of 1,376 BPD. Economically, the addition of a chiller modification project was feasible with the economical parameters of NPV US$ 132,000,000, IRR 348.19%, POT 0.31 year and PV ratio 19.06.

Background and Objective: The plasma electrolysis requires a high amount of energy at the beginning of the process. The purpose of the study was to examine how air injection could reduce the energy of plasma formation. Furthermore, the effect of the flow rate of injected air on hydroxyl radical production and Remazol Red degradation were also studied. Methodology: In this research, the air was injected directly through the glass sheath at the anode in Contact Glow Discharge Electrolysis reactor. Result: For the same energy input, the higher the flow rate of air injection, the radical hydroxyl concentration increased to an optimum point at a certain flow rate. Moreover, the rate of airflow at optimum condition increased with increasing voltage. An airflow rate of 0.05 L/min and a voltage of 600 Volts was the optimum condition. The concentration of hydroxyl radical at this condition produced 19.0849 mmol/L after 30 minutes. Conclusion: This was an increase of 48.43% in comparison with the amount of •OH where air injection was not used. The presence of air injection also increased the degradation of Remazol Red. Within 5 minutes, Remazol Red degradation had reached 86.37% at an airflow rate of 0.05 L/min. This indicated a 53.59% increase compared to the degradation process without air injection.

In waste, one of the important indicators is Chemical Oxygen Demand (COD). COD is the need for oxygen to oxidize organic substances contained in one liter of water. Chemical or chemical oxygen requirements for the oxidation reaction of waste materials in water. Chemical Oxygen Demand is an important water quality parameter because it can assess the effect of effluent from wastewater to be discharged into the receiving environment (water bodies). In this study, COD analysis was carried out using optimum conditions at 700 W and an air injection flow rate of 0.2 lpm, 0.02 M concentration of Na2SO4 electrolyte, 0.5 cm tungsten anode depth, 60°C of operating temperature, 100 mg/L initial phenol waste concentration, Fe2+ ion concentration 20 mg/L, volume of sample solution 1.5 L, and stirring speed 2 mot. The results showed a decrease in COD levels which only reached 71.14% due to cyclic chains in the widest area. Observation analysis of LC MS obtained the formation of intermediate compounds which include 2-Oxo-1.3-dioxole-4.5-dicarboxylic acid, ethyleneetetracarboxylic acid, and 2.2-oxydisuccinic acid.

In this study, phenol degradation in wastewater will be analyzed using the plasma electrolysis method with contact glow discharge. The plasma formed is influenced by the air sheath resulting from the injection of air at the electrodes. The stability of the gas envelope will form bright plasma and effectively produce radicals that degrade phenol in solution. Air injection is carried out at the electrodes to reduce evaporation so that it affects the energy consumption required in phenol degradation. Plasma electrolysis performance was carried out at air injection flow rates of 0 lpm, 0.2 lpm, 0.3 lpm, 0.4 lpm, 0.6 lpm and 0.8 lpm. Plasma electrolysis reactor process conditions on 500W, 600W and 700 W, temperature 60°C and 0.02 M electrolyte Na2SO4. Sampling for the analysis of phenol degradation was carried out at a time period of 0, 15, 30, 45, 60, 75 and 90 minutes. The results showed that the percentage increase in phenol degradation without air injection, air injection of 0 lpm, 0.2 lpm, 0.3 lpm and 0.4 lpm was 43.50%; 61.50%; 55.75%; and 48.27% at 500 W. At 600 W was 48%, 64%, 64% and 64%. At 700 W was 60%, 72%, 69% and 68%.

Researches about biodiesel synthesis have been studied by many researchers as commercial production of biodiesel has been implemented by most companies. The conventional method commonly used in biodiesel synthesis is transesterification process. Transesterification reaction with an alkali catalyst is preferred because it is faster and less corrosive than an acid catalyst. Nevertheless, reaction rate, energy consumption, and separation process of transesterification with alkali catalyst may be able to be improvised with a method that has a different reaction mechanism. Plasma electrolysis can produce many radical species and convert palm oil better than the conventional process. Therefore, this research aims to observe the effect reaction time, mixing rate, and the molar ratio of methanol-oil. The results showed that the mixing rate is the variable that has the most significant effect to yield of biodiesel and energy consumption. Also, reducing the molar ratio of methanol-oil from 24 : 1 to 18 : 1 can significantly accelerate the separation process. Based on this research, the optimum result is 92%-vol yield of biodiesel and 372 Jig energy consumption under condition molar ratio of methanol-oil 18 : 1, mixing rate is 500 rpm, and reaction time is 5 minutes.

Batik industry in Indonesia frequently dispose liquid waste containing high level of toxic and carcinogenic dyes to the drainage without being treated. In accordance with it, plasma electrolysis has been proved as the efficient method to degrade dyes waste, yielding higher hydroxyl radicals than other methods. The experiment was conducted by generating plasma in circulated reactor using stainless steel cathode and tungsten anode with 2 cm depth immersed in 0.02 M Na2SO4 electrolyte solution added by 20 mg/L Fe2+ and 100 mg/L of Remazol Red initial concentration, with addition of varying air injection rate at maintained power. The results show that 1 L/min is the optimum air injection rate value to operate this reactor effectively at 450 W of optimum operating power so that it could lower the breakdown voltage, reduce energy consumption, produce more OH radicals and other reactive species, and elevate the degradation percentage. The experiment conducted in optimum operating condition provide result of 99.61% in degradation percentage for 60 minutes with final concentration of dye is 0.39 mg/L, 41.55 mg/L of COD, and 3177.16 kJ of energy consumption.

Contact glow discharge electrolysis (CGDE) or plasma electrolysis technology is a proven effective method for degrading such kind of wastewater because it can produce •OH, H•, and other active species in large quantities responsible for breaking down phenol structure. This study aims to obtain high-efficiency phenol degradation using an injection of air directly through the anode. This research investigated the effect of the voltage to the current connections in CGDE in order to estimate the possibilities for an optimum electrical power on the phenol degradation. In this research, the production of hydrogen peroxide, the percentage of phenol degradation, and specific energy were used as the main research indicators. Experimental results show that each electrical power (500, 600, 700 watt) has an optimal value for the percentage of degradation. The optimal condition was found at 700 watt with the rate of air injection of 0.2 L/min. After the first 45 minutes, the phenol degradation was valued at 79.5%. Under the same conditions, with an addition of air injection, the phenol degradation shot up to 93.22%. Experimental results show that the largest phenol degradation was obtained at 99.48% after 90 minutes during the experiment. This research clarified that air injection on plasma anode could improve process efficiency.

Nitrogen is the important element for plants to live, and it just can be absorbed by plants in the simpler compounds form, which is nitrate. Plasma Electrolysis is a technology for the synthesis of new materials with the reactive species such as hydroxyl radicals and electrons are produced, including fixation of nitrogen from the air into nitrate solutions, which is the liquid fertilizer for plants. This research aims to determine how the nitrate solution can be formed through Plasma Electrolysis process and the influence of air flow rate as its raw material. The process is carried out at optimum power obtained from the results of plasma electrolysis current-voltage characterization. The concentration of nitrate formed was tested quantitatively using the UV-Vis spectrophotometry method. The results of this research show that the greater the air flow rate increase the nitrate productivity, but the specific energy consumption needed is decrease. Nitrate formed is able to reach 636.8 ppm at the highest air flow rate, which is 0.8 lpm. These results indicate that nitrates can be produced effectively by the Plasma Electrolysis method.

Nitrogen is the important element for plants to live, and it just can be absorbed by plants in the simpler compounds form, which is nitrate. Contact Glow Discharge Electrolysis (CGDE) is a technology for the synthesis of new materials with the reactive species such as hydroxyl radicals and electrons are produced, including fixation of nitrogen from the air into nitrate solutions, which is the liquid fertilizer for plants. This research aims to determine how the nitrate solution can be formed through CGDE process and the influence of potassium sulfate concentration as its electrolyte solution. The process is carried out at optimum power obtained from the results of plasma electrolysis current-voltage characterization. The concentration of nitrate formed was tested quantitatively using the UV-Vis spectrophotometry method. The results of this research show that the greater the concentration of electrolytes increase the nitrate productivity, but the specific energy consumption needed is decrease. Nitrate formed is able to reach 279.44 ppm at the highest K2SO4 concentration, which is 0.04 M. These results indicate that nitrates can be produced effectively by the CGDE method.

Plasma electrolysis is an advanced process of electrolysis using DC current to form electric sparks due to the electrons that undergo plasma excitation in the electrolyte solution. Plasma electrolysis produces hydroxyl radicals, a powerful oxidant, with greater amount than other advanced oxidation method, that is useful to degrade high molecular weight of organic compounds such as dye. This research aims to evaluate the degradation of batik dye waste which use Remazol Brilliant Blue (RBB) dye, using plasma electrolysis method with addition of microbubbles. Through the experiment which was carried out using 0.02 M Na2SO4, 150 mg/L of dye concentration, 40mg/L of FeSO4, 1cm anode depth, and 700 V of applied voltage, it's proven that the addition of microbubbles can increase hydroxyl radicals production and decrease energy consumption. The result of this research shows that the efficiency of dye degradation in addition of microbubbles is increased with 99.63% of percentage of degradation in 30 minutes, 0.56 mg/L of final dye concentration, 45.86 mg/L of COD, and 1162.47 kJ/mmol of specific energy.

Nitrogen is the most important substance in fertilizer to produce high quality harvest. Nitrogen, which comes from the air, can formed as ammonia and nitrate in fertilizer. In industry, the most common fertilizer contain ammonia not nitrate because of its production process easiness compared to nitrate. Ammonia has fertilization efficiency 40% and nitrate has fertilization efficiency 60%. Industrial fertilizer production process nowadays, ammonia synthesis which called Haber-Bosch process, still not environmental friendly and also consume high energy. Environmental friendly and lower energy process is needed to produce fertilizer. Some study related to nitrogen fixation to produce fertilizer has been made including plasma electrolysis method. Plasma electrolysis is an effective method to fix nitrogen from the air because of its ability to produce OH radicals and other radicals to break the N2 bound to produce nitrate with lower energy consumption compared to Haber-Bosch process. This method is implemented in batch reactor with variation of anode depth. This study has proven can produce nitrate up to 1,200 ppm in condition power 800 watt, anode depth 1.5-3.5 cm and Na2SO4 electrolyte concentration 0.02 M.

Contact Glow Discharge Electrolysis is a process of electrolysis with DC current to form electric sparks due to the electrons that undergo plasma excitation in the electrolyzed solution. Plasma electrolysis produce hydroxyl radicals, a powerful oxidant, with greater amount than other advanced oxidation method. This method is used to degrade much weight organic compounds such as dye. This research aims to evaluate the degradation of dye waste Remazol Brilliant Red (RBR) using Contact Glow Discharge Electrolysis method with air injection. The injection of air can increase hydroxyl radicals production and can decrease energy consumption. The condition used are dye concentration is 100 mg/L, NaCl 0,03 M, in addition of air bubbles and FeSO4 30mg/L applied power 450 W, and anode depth 2 cm. Dye degradation is measured by its absorbances with Spectrophotometer UV-Vis. The result of this research show that the efficiency of dye degradation in addition of microbubbles is increased with percentage of degradation was 99,63% in 30 minutes, final concentration of dye is 0,51 mg/L, COD 70.34 mg/L and specific energy is 3,129.395 kJ/mmol.

Synthesis of biodiesel by using plasma electrolysis is very promising. This study aims to obtain high efficiency in the synthesis of biodiesel from palm oil by using cathodic plasma electrolysis method. The raw materials are palm oil, methanol, and KOH catalyst. Variations consist of cathode depth and oil-methanol molar ratio. The highest yield of 98.76% is obtained on the condition of cathode depth of 3.5 cm and oil:methanol molar ratio of 1:24. The lowest specific energy consumption of 605 J/ml is obtained on the condition of cathode depth of 3.5 cm and oil-methanol molar ratio of 1:12. High process efficiency is proved to be obtained by the use of cathodic plasma. These results indicate that cathodic plasma electrolysis method is effective to be used in the synthesis of biodiesel.

Background and Objective: Plasma anode has been known as a very productive method of producing hydroxyl radicals that oxidize effectively in almost all organic and non-organic liquids. This research was conducted to investigate the effect of air injection and anode depth variation on required energy for plasma generation and production of hydroxyl radicals. Material and Method: A batch reactor (diameter 130 mm, height 190 mm) with tungsten electrodes (cathode diameter 6 mm and anode diameter 0.5 mm) was used by applying a continuous cooling system. The experimental parameters were composed of different rate of air injection (0, 2, 4, and 6 Lmin-1) and various depth of anode (5, 25, 45, and 65 mm). Current was observed at various voltage (20 – 700 V) in 30 second for each voltage. Result: The energy consumption of plasma formation was getting smaller at higher rate of air injection, while at deeper anode position, the energy consumption found higher. Although the •OH production became lower at a higher rate of air injection, the process efficiency observed higher. Conclusion: This research clarified that air injection on plasma anode and the anode depth position affected the energy consumption and production of hydroxyl radicals where the addition of air injection and variation of the anode depth could reduce energy consumption and also improved process efficiency.

Multi-Contact Glow Discharge Electrolysis (m-CGDE) technique have successfully degraded linear alkylbenzene sulfonate (LAS) surfactant with high efficiency. The degradation process was conducted in 0.02 M electrolyte solution NaOH with electrical voltage at 800 V and anode at 10 mm depth. The anode number and addition of Fe 2+ ion greatly influenced the efficiency of the degradation. In the experiment using number of anode of 4, the percentage of LAS degradation achieved approximately 99.46% in 90 min, with energy consumption of 721.06 kJ/mmol. The addition of Fe 2+ ions will increase the LAS degradation, by using 40 mg/L of Fe 2+ ions in the reactor, LAS was degraded approximately 97.95% and 807.82 kJ/mol energy consumed during the operation.

In the plasma electrolysis process, hydrogen generation around the cathode is affected by the amount of evaporation energy. Utilizing a veil, minimizing the cooling in the liquid phase, and maximizing the cooling in the gas phase become important parameters to improve the process efficiency of hydrogen production. This research aims to obtain an optimum high-efficiency electrolysis plasma reactor based on decreased energy consumption and increased hydrogen gas production. The research method varied the NaOH concentration, voltage, veil length, cathode depth, and the volume of the methanol additive. In characterizing the current and voltage, as the concentration increases, the voltage needed to form the plasma will decrease. As the concentration and voltage increase, the rate of production, hydrogen content percentage, and the hydrogen ratio also increase, while the energy consumption decreases. The optimum condition, based on variations of veil length, is 5 cm when the depth of the cathode is 1 cm below the surface of the solution. Improving the efficiency of the hydrogen production process can be done by adding methanol. The best result was achieved using 15% volumes of methanol additive in 0.01 M NaOH, and higher hydrogen-ratio plasma-electrolysis results were found in comparison with Faraday electrolysis: the hydrogen ratio was 151.88 mol/mol, the lowest energy consumption was 0.89 kJ/mmol, and the highest hydrogen production rate was 31.45 mmol/min. The results show that this method can produce hydrogen 152 times more than Faraday electrolysis.

Fertilizer is the most important thing in agriculture to nourish the plant to produce high quality harvest. The most important element in fertilizer is nitrogen which comes from the air. The form of nitrogen in fertilizer are ammonia with fertilization efficiency 40% and nitrate with fertilization efficiency 60%. The recent industrial fertilizer production process, ammonia synthesis which called Haber-Bosch process, still not environmentally friendly and also consume high energy. Environmentally friendly and lower energy process is needed to produce fertilizer. Some study related to nitrogen fixation to produce fertilizer has been made including Contact Glow Discharge Electrolysis (CDGE). Contact Glow Discharge Electrolysis (CGDE) is an effective technology to fix nitrogen from the air into the solutions because of its ability to produce reactive species such as hydroxyl radicals and electrons to break the N2 bond and transfer it into the solution. This study is comparing CDGE in Na2SO4 solution and K2SO4 solution and will be implemented in batch reactor, in 600 and 800 watts, in 0.02 M concentration, anode depth 1.5 and 3.5 cm, with air injection flow rate 0.2 liter per minute as the source of nitrogen and 1,5 liter of solution is used. Plasma in K2SO4 had better nitrate production in both conditions used.

Latex has excellent flexibility, but poor of stiffness modulus. While starch is a polymer that widely used to improve the mechanical property such as stiffness modulus. The formation of latex-starch hybrid through grafting reactions is a solution to improve mechanical property of latex. However, polarity differences caused both to be difficult to mix. One method that can overcome this problem is contact glow discharge electrolysis (CGDE) which produces high energy in the process which can trigger the formation of bonds. The synthesis process was carried out using cathodic plasma with 1% -wt concentration of latex, the ratio of latex: starch was 100: 25, electrolyte Na2SO4 0.02 M, temperatures maintained at 60 oC for 30 minutes. This study aims to examine the effects of ethanol additives addition (5%v and 10%v) and air injection to the yield of latex-starch hybrid. The result shows that after adding ethanol with a concentration of 5%v and 10%v, the latex-starch hybrid production is decreased by 16.28% and 18.89% respectively. This study also shows that in the 30th minutes, the synthesis using air injection reached 65.81%; 16.60% higher than normal synthesis with cathodic plasma.

This study aims to determine the effect of pH of the solution and conductivity on the yield of nitrates formed. The method is carried out by plasma electrolysis made from air injection. The electrolyte solution used is a mixture of K2HPO4 and K2SO4. The pH condition of the solution is getting longer decreasing also has an effect due to acidic nitrate ions which are more formed if dissolved in water. If the condition of the solution the more acidic, the absorption power of NO2 gas formed in the solution to to NO3 will decrease further, so that over time resulting in the production of nitrates in the solution will decrease. The research results showed that for 120 minutes the processing time was large The pH decreases due to the formation of acidic nitrates. Decreased pH can also be caused by H2O2 production. In minute 0 to minute 5, a significant decrease in pH of 2.99. This is due to accretion nitrate product for 5 minutes the process is very significant that is equal to 1277 ppm. While the decrease in pH at minute 5 to minute 120 is less significant, where the pH decreases around 0.09 to 0.02 due to increase nitrate products are not as large as 5 minutes of processing time. Then, the more acidic the solution causes nitrate production to decrease. In acidic conditions, absorption of NO2 gas formed in the solution to be converted to NO3 will decrease. The concentration of an electrolyte solution affects the conductivity of a solution, where the higher the concentration of an electrolyte solution, the conductivity of a solution will also be even greater. The amount of conductivity will affect the speed at which a plasma is formed.

Contact Glow Discharge Electrolysis (CGDE) is one of the plasma electrolysis technologies for producing hydroxyl radicals that can be used for the process of waste degradation. This study has been conducted to establish the influence of voltage, electrolyte concentration, and anode depth in the Linear Alkylbenzene Sulfonate (LAS) degradation process using CGDE and its energy consumption. The results indicated that the greatest LAS degradation at a rate of 96.19% was achieved with an energy consumption of 2692 kJ/mmol, that was obtained using 600 V, at a Na2SO4 concentration of 0.03 M, and anode depth of 20 mm during 30 minutes of the process. Meanwhile, the lowest energy consumption was 1802 kJ/mmol with the LAS degradation at the rate of 82.11% that was obtained when using 600 V, at a Na2SO4 concentration of 0.03 M and anode depth of 0.5 mm during 30 minutes of the process. These results showed that CGDE is an effective method to degrade LAS. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 962–968, 2016

Background and Objective: There are many Small, Micro and Medium Enterprises engaged in tofu processing in Indonesia. Some of them still dumped their waste directly into the river, causing the river to become turbid, had bad odor, and many aquatic organisms in the water died. Tofu wastewater contained high pollutant parameters, such as: COD, BOD, TOC, and TSS therefore, we need an effective wastewater treatment that could reduce the level of these parameters to below the standards set by the government. Materials and Methods: We used Contact Glow Discharge Electrolysis (CGDE) to treat the wastewater. Besides these four parameters, we also measured pH solution at several CGDE process voltage variations and analyzed the content of compounds contained in the initial tofu wastewater and the waste that had been treated by using CGDE. Results: From this study, we knew that the higher the voltage we used, the more acidic the solution would become. In the same operating condition, the percentage of TOC degradation was lower than the percentage of COD degradation. Voltage of 750 V gave the lowest COD and TOC values, respectively 446.6 mg/L and 320 mg/L. In addition, the best voltage that could reduce BOD and TSS degradation by 37% and by 80.2% respectively, was 650 V. Conclusion: CGDE process was able to degrade complex compounds in tofu wastewater into compounds with simpler molecular structures, such as Tris (2,4-di-tert-butylphenyl) phosphate and eicosane.

Limbah pewarna industri tekstil merupakan limbah cair yang sulit teroksidasi dan berbahaya bagi lingkungan. Radikal hidroksil (•OH) merupakan spesies yang sangat efektif dalam mengoksidasi berbagai limbah cair organik seperti limbah pewarna. Metode Elektrolisis Plasma sangat produktif menghasilkan radikal Hidroksil sehingga efektif dalam menyisihkan (mendegradasi) berbagai jenis limbah pewarna tekstil seperti Remazol Red. Penelitian ini bertujuan mengoptimalkan proses degradasi remazol red RB 133 dan konsumsi energinya menggunakan metode Elektrolisis Plasma melalui pengaturan suhu dan injeksi gelembung udara dalam larutan. Pembentukan H 2 O 2 merupakan indikator pembentukan •OH pada reaksi Elektrolisis Plasma. Injeksi udara pada larutan limbah pewarna menurunkan arus listrik pada kurva karekateristik arus-tegangan. Kenaikan suhu larutan dari 45 o C menjadi 75 o C selama 10 menit reaksi tampa injeksi udara menurunkan konsumsi energi dari 229,9 kJ menjadi 219,5 kJ serta menurunkan produksi H 2 O 2 dari 4,8 mmol menjadi 3,1 mmol. Sementara injeksi udara pada suhu 75 o C selama 10 menit proses menurunkan konsumsi listrik hingga 28,5% dan meningkatkan produksi H 2 O 2 hingga 27,3 %. Namun demikian injeksi udara hanya meningkatkan degradasi Remazol Red sebesar 1,8 %. Suhu optimum dicapai pada 55 o C, dengan produksi H 2 O 2 sebesar 5,7 mmol selama 30 menit. Injeksi udara udara mampu meningkatkan efektivitas proses. Hasil penelitian menunjukkan persen penyisihan mencapai 88,9% dengan konsumsi energi sebesar 115,2 kJ dalam waktu 30 menit reaksi. Kata kunci : elektrolisis plasma, remazol red, gelembung udara. Abstract . Effect of Temperature and Air Injection on Degradation of Remazol Red Textile Dyes by Plasma Electrolysis Method . The textile dye waste is a liquid waste that is difficult to oxidize and dangerous for the environment. Hydroxyl radicals (• OH) are very effective species in oxidizing various organic liquid wastes such as Remazol Red. Plasma Electrolysis Method is very productive in producing Hydroxyl radicals, resulting in effective degradation of various types of textile dye waste such as Remazol Red. This study aims to optimize the degradation process of remazol red RB 133 and its energy consumption using the Plasma Electrolysis method through temperature regulation and injection of air bubbles in solution. The formation of H 2 O 2 is used an indicator of the formation of •OH in the Plasma Electrolysis reaction. The Air injection decreases the electric current on the current-voltage characteristic curve. The solution temperature increases from 45 o C to 75 o C for 10 minutes reaction without air injection were able to reduce the energy consumption from 229.9 kJ to 219.5 kJ and H 2 O 2 production from 4.8 mmol to 3.1 mmol. Meanwhile, the addition of air injection at 75 o C within 10 minutes of reaction were able to reduce electricity consumption by 28.5% and increases H 2 O 2 production by 27.3%. However, the addition of air injection only increased the degradation of Remazol Red by 1.8%. The optimum temperature was reached at 55 o C, with H 2 O 2 production of 5.7 mmol for 30 minutes. The addition of air injection has been shown to increase the effectiveness of the process. The results showed degradation percentage reached 88.9% with energy consumption of 115.2 kJ within 30 minutes of reaction. Keywords : air injection, plasma electrolysis, remazol red. Graphical Abstract

Contact glow discharge electrolysis (CGDE) is a proved plasma electrolysis method effectively used for the treatment of organic wastewater. This study investigated the decolorization process of three textile dyes (Remazol Red RR, Remazol Yellow FG, and Remazol Brilliant Violet) using CGDE aided by air injection. The results indicated that air injection was able to increase the decolorization of Remazol Red RR up to 46.7 % in 180 min. In addition, using this method resulted in good decolorization efficiencies with the three dyes (11,520, 24,412.5, and 8,820 kJ/mmol for Remazol Red RR, Remazol Yellow FG, and Remazol Brilliant Violet, respectively).

This research determined the optimum concentration of Fe2+ to degrade waste textile dye by Contact Glow Discharge Electrolysis (CGDE) method with air injection. The addition of Fe2+ ions can increase the degradation rate of the dye waste due to the radical catalytic conversion of H2O2 producing OH radicals that play a significant role in the degradation process. Remazol Red was used as a dye synthetic dye which was degraded using a batch reactor equipped with continuous cooling water. Experimental results showed that waste concentrations of 100, 200, 300 and 400 ppm obtained the optimum Fe2+ concentration at 10, 20, 30 and 40 ppm, respectively. The higher concentration of dye waste indicated the higher the Fe2+ ion requirement to decrease the textile dye waste.

Plasma electrolysis has been proved have much higher effectivity in degrading complex pollutant contained in batik dye wastewater. This study aims to investigate the effect of gas bubbles with air injection of plasma electrolysis in decolorization process. A new method to form bubbles using injection of air directly through anode with a tiny hole of glass tube is proposed. This research work presents the effects of gas injection rates on various phenomena such as electrical power of discharge pulses, concentration of OH radicals, and the decolorization percentage of remazol red as the dye waste in a batch reactor system. Experimental results showed that direct injection of air through anode can reduce the required energy for plasma generation significantly compared to non gas injection. Energy consumption for discharge plasma was observed lowered at higher rates of gas injected. Optimum gas flow rate at different voltage has been evaluated based on the physical and chemical characteristics of plasma. At higher required energy due to higher operation voltage used, the required gas injection rate to effectively degrade the waste was found higher.

Phenol and Cr (VI) are two types of wastewater known as dangerous and difficult to degrade. Through this study, phenol and Cr (VI) metal wastewater were degraded simultaneously using plasma electrolysis method by reactive species, •OH and H•. The variation of anode depth and position of plasma formation as independent variables correlated with yield of hydroxyl radical, percentage of phenol and Cr (VI) degradation, and specific energy. Within 30 minutes, phenol was degraded to 98.4% and Cr (VI) was degraded to 93.35% with 171.05 kJ/mmol in specific energy, and 174.53 ppm in COD. The optimum condition was obtained in anodic plasma and 1.5 cm in anode depth. The highest degradation percentage of phenol and Cr (VI) were 99.79% and 97.33% achieved during 180 minutes of plasma electrolysis process.

Contact Glow Discharge Electrolysis (CGDE) method is one of Plasma Electrolysis technology which has been approved to degrade organic waste water because it is very productive in producing hydroxyl radical. This study aims to degrade Remazol Red by CGDE method and evaluate important parameters that have influent in degradation process of Remazol Red in Batik dye waste water in batch system. The kind of electrolyte (acid and base) and the addition of metal ion such as Fe2+ have affected Remazol Red degradation percentage. Ultraviolet-Visible (UV-Vis) absorption spectra were used to monitor the degradation process. The result of study showed that percentage degradation was 99.97% which obtained by using NaCl 0.02 M with addition Fe2+ 20 ppm, applied voltage 700 volt, anode depth 0.5 cm, initial concentration of Remazol Red 250 ppm and the temperature of solutions was maintained 50-60 ˚C.