• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.05a
• /
• pp.406-409
• /
• 1999

Experimental Investigations were carried out to remove NOx, SOx simultaneously from simulated flue gas[NO(0.02%)-SO$_2$(0.08%)-$CO_2$-Air-$N_2$] by using a plasma chemical reaction. Ammonia gas(14.81%) balanced by argon was diluted by all and was Introduced to mall simulated flue gas duct through NH$_3$ Injection system which is in downstream of reactor. The NH$_3$ molecular ratio(MR) was determined based on (NH3) to [NO+S0$_2$]. MR is 1, 1.5, 2.5. The NOx removal rate significantly increased with increasing NaOH bubble quantity. The SO$_2$ removal rate was not significantly effected by applied voltage, however it fairly Increased with increasing NH$_3$ molecule ratio. By-product aerosol particle was observed by XRD(X-ray diffraction) after sampling, The NOx, SOx removal rates, when H2O vapour bubbled by dry all was injected to plasma reactor, were better than those of other cases. When aqueous NaOH solution(20%) bubbled by 2.5( ι /min) of $N_2$ and 0.5 ( ι /min) NH$_3$(MR=1.5) were injected to simulated flue gas, The NOx. SOx removal rate was 95 ~ 100[%]

• Proceedings of the KIEE Conference
• /
• 1999.07e
• /
• pp.2007-2009
• /
• 1999

In this paper, discharge domain of wire-cylindrical plasma reactor was separated from a gas flow duct to avoid unstable discharge by aerosol particle deposited on discharge electrode and grounded electrode. The NOx, SOx removal was experimentally investigated by a reaction induced to ammonium nitrate, ammonium sulfate using a low price of aqueous NaOH solution and a small quantity of ammonia. Volume percentage of aqueous NaOH solution used was 20% and $N_2$ flow rate was 2.5[$\ell$/min] for bubbling aqueous NaOH solution. Ammonia gas(14.82%) balanced by argon was diluted by air and was introduced to a main simulated flue gas duct through $NH_3$ injection system which was in downstream of reactor. The $NH_3$ molecular ratio[MR] was determined based on $NH_3$ to [NO+$SO_2$]. MR is 1.5. The NOx removal rates increased in the order of DC, AC and pulse, but SOx removal rates was not significantly effected by source of electricity. The NOx removal rate slightly decreased with increasing initial concentration but SOx removal rate was not significantly effect by initial concentration, and NOx, SOx removal rates decreased with increasing gas flow rate.

• Journal of Wetlands Research
• /
• v.23 no.1
• /
• pp.54-59
• /
• 2021

DIWS system was introduced to remove hydrogen sulfide from the biogas of wastewater treatment plant. In the case of using water into the DIWS system more than 5,000mg/L of hydrogen sulfide, 25% of H2S removal efficiency was shown and required such further treatment process as incineration which was obtained more than 98%. When the inflow of hydrogen sulfide was 5,000mg/L, CH4 and CO2 were effectively discharged and the reduction was 8.7% and 28.6%, respectively. When such neutralization chemicals as Na2CO3 and NaOH were introduced into the DIWS system, H2S was removed more than 97.2% keeping pH in the range of 11.2 to 11.5.

• Advances in environmental research
• /
• v.8 no.1
• /
• pp.23-38
• /
• 2019

In this study, Malachite Green (MG) dye removal from synthetic wastewaters by adsorption process using raw boron enrichment waste (BEW) and it's modifications (with acid and ultrasound) were aimed. 81% MG removal was obtained by BEW at optimum equilibrium conditions (time: 40 min., dosage: 500 mg/dm³, pH: 5-6, speed: 200 rpm, 298 K). MG removal from wastewaters using acid modified boron enrichment waste (HBEW) was determined as 82% at optimum conditions (time: 20 min., dosage: 200 mg/dm³, pH: 10, speed: 200 rpm, 298 K). For ultrasound modified BEW (UBEW), the highest MG removal percent was achieved as 84% at optimum conditions (time: 30 min, dosage: 375 mg/ dm³, pH: 8, speed: 200 rpm, 298 K). The equilibrium data of Malachite Green was evaluated for BEW, HBEW and UBEW adsorbents by using sorption isotherms such as Langmuir, Freundlich and Temkin models, out of which Langmuir model (R² = 0.971, 0.987 and 0.984) gave better correlation and maximum adsorption capacity was found to be 147.05, 434.78 and 192.30 mg/g, respectively. The adsorption kinetics followed the pseudo-second-order kinetic equation for sorption of MG onto wastes. A look at thermodynamic data reveals that natural sorption is spontaneous and endothermic because of free negative energy exchange and positive change in enthalpy, respectively. The results indicated that boron enrichment waste, and HCl and ultrasound-modified boron enrichment waste served as good alternative adsorbents in dye removal from wastewater.

• Journal of Environmental Science International
• /
• v.17 no.5
• /
• pp.547-553
• /
• 2008

For the RhB removal from the wastewater, electrochemical method was adapted to this study. Three dimensionally stable anode (Pt, Ir and Ru) and graphite and Ru cathode were used. In order to identify decolorization, the effects of electrode, current density, electrolyte and air flow rate were investigated. The effects of electrode material, current, electrolyte concentration and air flow rate were investigated on the decolorization of RhB. Electro-Fenton's reaction was evaluated by added $Fe^{2+}$ and $H_2O_2$ generated by the graphite cathode. Performance for RhB decolorization of the four electrode systems lay in: Ru-graphite > Ru-Ru > Ir-graphite > Pt-graphite. A complete color removal was obtained for RhB (30 mg/L) at the end of 30 min of electrolysis under optimum operations of 2 g/L NaCl concentration and 2 A current. $Fe^{2+}$ addition increased initial reaction and decreased final RhB concentration. However the effect was not high.

• Applied Chemistry for Engineering
• /
• v.31 no.5
• /
• pp.495-501
• /
• 2020

In this study, zirconium fumarate of metal-organic framework (MOF-801) was solvothermally synthesized at 130 ℃ and characterized through powder X-ray diffraction (PXRD) analyses and porosity measurements from N₂ sorption isotherms at 77 K. The ability of MOF-801 to act as an adsorbent for the phosphate removal from aqueous solutions at 25 ℃ was investigated. The phosphate removal efficiency (PRE) obtained by 0.05 g/L adsorbent dose at an initial phosphate concentration of 60 ppm after 3 h was 72.47%, whereas at 5 and 20 ppm, the PRE was determined to be 100% and 89.88%, respectively, after 30 min for the same adsorbent dose. Brunauer-Emmett-Teller (BET) surface area and pore volume of the bare MOF-801 sample were 478.25 ㎡/g and 0.52 ㎤/g, respectively, whereas after phosphate adsorption (at an initial concentration of 60 ppm, 3 h), the BET surface area and pore volume were reduced to 331.66 ㎡/g and 0.39 ㎤/g, respectively. The experimental data of kinetic (measured at initial concentrations of 5, 20 and 60 ppm) and isotherm measurements followed the pseudo-second-order kinetic equation and the Freundlich isotherm model, respectively. This study demonstrates that MOF-801 is a promising material for the removal of phosphate from aqueous solutions.

• Journal of Electrochemical Science and Technology
• /
• v.13 no.2
• /
• pp.261-268
• /
• 2022

In this study, electrochemical treatment of urban wastewater with electrical conductivity of 1000 μS cm^-1 and chemical oxygen demand of 250 mg L^-1 was investigated using the variables of initial pH value, current density and flow rate. Electrocoagulation was used, in which aluminum and stainless steel were selected, as the electrochemical treatment process. The electrocoagulation process was operated in continuous mode. The data obtained in experimental studies show that the best COD removal efficiency occurred in experiments where the initial pH value was 6. The increase in current density from 5 A to 15 A decreased the removal efficiency from 79 to 67%. The increase in flow rate under constant current density also reduced the efficiency of removal as expected. In experiments in which current density and flow rate were examined together, the increase in flow rate allowed the application of higher current densities. This situation led to considerable reductions in energy consumption values, even if the COD removal efficiency did not significantly increase. The high COD removal obtained with the use of high flow rate and high current density indicates that the electrocoagulation process can be used for high flow rate municipal wastewater treatment.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.20 no.4
• /
• pp.655-666
• /
• 1996

The effect of protease (subtilisin Carlsberg) on the removal of hemoglobin as protein soil was studied. The relation between the renloval and the hydrolysis of hemoglobin by subtilisin Carlsberg was discussed. The soiled babric was prepared by spotting of hemoglobin solution evenly on the cotton fabric and was denatured by steaming. The soiled fabric was washed by using Terg-0-Tometer at various conditions. The removal efficiency was evaluated by analysis of protein on the fabrics before and after washing by means of copper-Folin method. 1. The removal of hemoglobin was increased in proportion to increasing of the enzyme concentration up to a certain point, but it began to decrease above the point. 2. The hemoglobin was removed effectively by adding of subtilisin Carlsberg, and more effectively removed by adding of AOS in the enzyme solution. 3. The removal of hemoglobin deviated from the first order reaction in detergency. 4. The renloval of hemoglobin was highest at $50^{\circ}C$ in detergency, Even at low temperature the removal efficiency of enzyme was relatively higher compared with the hydrolysis of hemoglobin by the enzyme. However the removal of hemoglobin was apparently decreased with the increase of temperature over $60^{\circ}C$. 5. The removal of hemoglobin was relatively high at pH 7.0~8.0 and increased continuously with the increase of pH in detergency 6. In detergency, the removal mechanism of hemoglobin by subtilisin Carlsberg could be explained as follows: Fisrt of all, the enzyme hydrolyzed hemoglobin substrates partially by forming E-S complex at the surface of hemoglobin on the cotton fiber, and decomposed cooperative binding of hemoglobin. Subsequently, the fragments of hemoglobin were easily removed by washing. According as the enzyme penetrated to inner part of hemoglobin gradually, the hemoglobin on the cotton fiber was effectively removed by the repetition of these process. The removal of hemoglobin was more effectively increased by adding both the enzyme and AOS in the washing solution. Therefore, it was regarded that AOS molecules were adsorbed at the hydrophobic surface of denatured hemoglobin, subsequently, decomposed more effectively cooperative binding of hemoglobin, and the fragments of hemoglobin were removed more efficiently by means of the interfacial reaction of AOS.

• Analytical Science and Technology
• /
• v.19 no.2
• /
• pp.181-187
• /
• 2006

This study was carried to survey the removal characteristics of BPA using coagulation process by PAC and PAHCS. BPA removal for PAC and PAHCS was 20.4 with 8.7 Al mg/L and 6.8 Al mg/L, respectively. Removal of BPA was lower than $UV_{254}$ and DOC but removal characteristics were similar. BPA removal for PAC and PAHCS was most high in pH 6.5 and 7.0 respectively. The time for removal by mixing time was 40 min in PAC and 30 min in PAHCS. When powdered activated carbon 50 mg/L was added in coagulation process, a high remove of BPA (61%) was noticed. Specially BPA was highly increase powdered activated carbon 5 mg/L alone. These results will be appliable in the conventional water treatment plants for improvement of water treatment system.

• Transactions of Materials Processing
• /
• v.18 no.2
• /
• pp.172-176
• /
• 2009

In this paper, new aspherical surface polishing mechanism is suggested to polish aspherical glass lens mold by both airbag polishing tool and reverse-rotational eccentric motion. Up to now, conventional aspherical lens polishing method by the small tool polishing uses the aspherical surface profile and the trajectory of the polishing tool is also controlled. However, full contact concept by airbag polishing tool and no position control make the easy polishing setup and does not need aspherical design profile. An aspherical lens polishing machine was made for this study and a tool mark removal experiment fur the fine-grounded lens mold was successfully performed.