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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 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%.

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. 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.

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.

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.

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.

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.

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.

Phenol and Cr (VI) are an organic waste and dangerous heavy metals which generated from a wide variety of industrial processes such as textiles, paints, dyes, and others. For that reason, we need effective waste treatment technologies, one of them is Contact Glow Discharge Electrolysis (CGDE). This method produce reactive species such as radical hidroxyl so as to be able to degradate phenol and Cr(VI) wastewater effectively. This research aims to obtain the effect of Fe 2+ and air bubbles in degradation of phenol and Cr (VI) waste simultaneously. Waste degradation is measured its absorbance with UV-Vis spectrophotometer. In the conditions of 600 Volt voltage, Na2SO4 0.02 M, anode depth of 1.5 cm, the addition of Fe2+ 40 ppm and the addition of air bubbles for 30 minutes was obtained a percentage degradation of phenol 99.47%, Cr (VI) 76.75% and specific energy of 344.473 kJ / mmol.

This research has evaluated the use of Contact Glow Discharge Electrolysis method in the synthesis of biodiesel. The purpose of this research is to get the synthesis process and biodiesel product. The solution used is the mix of Crude Palm Oil and methanol with molar ratio of 1:24, and catalyst of NaOH and KOH with variation of concentration 0.5% - 1.5%-wt. The result shows that the biodiesel can be made from transesterification reaction that may be initiated by radical methoxide. The use of electrolyte KOH is better than NaOH based on the yield of biodiesel and the energy consumption. The optimum yield reaches 97%, at the synthesis for 30 minutes with the use of KOH 1%-wt with the energy consumption of 1.32 kJ/mL.

Remazol Brilliant Blue dye waste is one of the liquid waste produced from the textile industry and harmful to the environment. Contact Glow Discharge Electrolysis (CGDE) method is an effective method to degrade dye waste by producing OH radicals which will be used in liquid waste degradation process. This study aims to determine the effect of anode depth, temperature, and flow rate of air injection on the production of hydroxyl radicals and dye degradation of Remazol Brilliant Blue. This research was conducted in batch reactor with electrolyte NaCl 0,03 M. Variation which done is anode depth which is 0,5 cm; 2 cm; 4 cm, temperature of 40°C; 50°C; 60°C, and air injection flow rate of 0 lpm and 2.5 lpm. The research was conducted by voltage - current characteristic test, hydroxyl radical production test, and dye degradation test. Remazol Brilliant Blue degradation reached 96.15% within 30 minutes where the tension was 750 V, 0.03 M NaCl solution concentration, Fe2+ 40 ppm, 2 cm anode depth, 50°C temperature, and 2.5 lpm air injection flow rate.

Tofu wastewater is one of the most dangerous source of environmental pollutants. It is known that the COD of tofu wastewater can reach 8000 mg/L. Contact Glow Discharge Electrolysis (CGDE) method is an effective method in degrading complex pollutants contained in tofu wastewater, due to its ability to produce large quantities of OH radicals. This study aims to test the ability of the CGDE method in degrading the tofu wastewater by the addition air injection. In this method, several variations were made to determine the optimal airflow rate and initial concentration of tofu wastewater. Tofu wastewater degradation reached 73% for 120 minutes, with the final value of COD is 425 mg/L and BOD is 447 mg/L. Maximum conditions are obtained by using airflow rate 2.5 lpm, temperature 50°C, and initial concentration of tofu wastewater is 2000 ppm. The addition of air injection with airflowrate 2.5 lpm is able to reduce energy consumption by 37%. The results show that CGDE with air injection has the potential to degrade pollution parameter in tofu wastewater.