The aim of this research was to apply experimental design methodology in the optimization condition of electrochemical oxidation of Rhodamine B(RhB). The reactions of electrochemical oxidation were mathematically described as a function of parameters amounts of current, NaCl dosage, pH and time being modeled by the use of the central composite design, which was used for fitting quadratic response surface model. The application of response surface methodology using central composite design(CCD) technique yielded the following regression equation, which is an empirical relationship between the removal efficiency of RhB and test variable in actual variables: RhB removal (%) = 3.977 + 23.279․Current + 49.124․NaCl － 5.539․pH － 8.863 ․time － 22.710․Current․NaCl + 5.409․Current․time + 2.390․NaCl․time + 1.061․pH․time － 0.570․time2. The model predicted also agree with the experimentally observed result(R2 = 91.9%).

This study has carried out to evaluate the effect of NaCl as electrolyte of single (electrolysis and UV process) and complex (electrolysis/UV) processes for the purpose of removal and mineralization of Rhodamine B (RhB) dye in water. It also evaluated the synergetic effect on the combination of electrolysis and UV process. The experimental results showed that RhB removal of UV process was decreased with increase of NaCl, while RhB removal of electrolysis and electrolysis/UV process was increased with increase of NaCl. The decolorization rate of the RhB solution in every process was more rapid than the mineralization rate identified by COD removal. The latter took longer time for further oxidation. Absorption spectra of an aqueous solution containing RhB showed a continued diminution of the RhB concentration in the bulk solution: concomitantly, no new absorption peaks appeared. This confirmed the decolorization of RhB, i.e., the breakup of the chromophores. It was observed that RhB removal in electrolysis/UV process is similar to the sum of the UV and electrolysis. However, it was found that the COD of RhB could be degraded more efficiently by the electrolysis/UV process than the sum of the two individual process. A synergetic effect was demonstrated in electrolysis/UV process.

피부주름 개선에는 콜라겐(collagen)뿐만 아니라 탄력섬유인 엘라스틴(elastin) 등도 기여하는 것으로 보고되고 있다. 더 나아가 자외선에 의하여 사람의 피부에서 광노화 현상이 나타나며 자외선 조사 후 엘라스타제(elastase)의 활성이 증가하기 때문에 엘라스타제의 활성증가는 자외선에 의한 피부 탄성도의 감소 및 주름 생성의 주요원인으로 생각된다. 따라서 본 연구에서는 피부주름 생성에 영향을 미치는 엘라스타제의 활성을 측정하기 위한 모델을 마련하기 위하여 시판되는 두 가지 엘라스타제, 돼지 췌장 엘라스타제(porcine pancreatic elastase)와 사람 호중구 엘라스타제(human neutrophil elastase)를 사용하였으며 다음 세 가지는 정상 사람 섬유아세포(normal primary human fibroblasts), 쥐의 3T3 섬유아세포주(3T3 mouse fibroblasts), 사람의 CCD-25Sk 섬유아세포주(CCD-25Sk human fibroblasts)로부터 elastase를 준비하여 사용하였다. 준비된 5가지 효소의 농도에 기질의 농도 및 배양시간에 따르는 효소의 활성을 비교 평가하였다. 양성대조군으로 사용한 phosphoramidon이 normal human primary fibroblast elastase와 CCD-25Sk fibroblast elastase의 활성을 유의성 있게 억제한 반면에 porcine pancreatic elastase에는 별다른 영향을 미치지 못하였다. 따라서 주름 개선 후보물질 탐색을 위한 엘라스타제의 선정에는 신중한 고려가 필요할 것으로 사료된다.

Fabrication and oxidants production of 3 or 4 components metal oxide electrode, which is known to be so effective to destruct non-biodegradable organics in wastewater, were studied. Five electrode materials (Ru as main component and Pt, Sn, Sb and Gd as minor components) were used for the 3 or 4 components electrode. The metal oxide electrode was prepared by coating the electrode material on the surface of the titanium mesh and then thermal oxidation at 500℃ for 1 h. The removed RhB per 2 min and unit W of 3 components electrode was in the order: Ru:Sn:Sb=9:1:1 > Ru:Pt:Gd=5:5:1 > Ru:Sn=9:1 > Ru:Sn:Gd=9:1:1 > Ru:Sb:Gd=9:1:1. Although RhB decolorization of Ru:Sn:Sb:Gd electrode was the highest among the 4 components electrode, the RhB decolorization and oxidants formation of the Ru:Sn:Sb=9:1:1 electrode was higher than that of the 3 and 4 components electrode. Electrogenerated oxidants (free Cl and ClO2) of chlorine type in 3 and 4 components electrode were higher than other oxidants such as H2O2 and O3. It was assumed that electrode with high RhB decolorization showed high oxidant generation and COD removal efficiency. OH radical which is electrogenerated by the direct electrolysis was not generated the entire 3 and 4 components electrode, therefore main mechanism of RhB degradation by metal oxide electrode based Ru was considered indirect electrolysis using electrogenerated oxidants.

Fabrication and oxidants formation of 1 and 2 component metal oxide electrode, which is known to be so effective to destruct non-biodegradable organics in wastewater, were studied. Five electrode materials (Ru, Pt, Sn, Sb and Gd) were used for the 1 and 2 component electrode. The metal oxide electrode was prepared by coating the electrode material on the surface of the titanium mesh and then thermal oxidation at 500℃ for 1 h. The removed RhB per 2 min and unit W for one component electrode decreased in the following sequences: Ru/Ti > Sb/Ti > Pt/Ti > Gd/Ti > Sn/Ti. The concentration of oxidants generated in 1 and 2 component electrodes was in the order of: ClO2 > free Cl > H2O2 > O3. OH radical was not generated from in entire one and two component electrodes. RhB degradation rate and generated oxidants of the Ru-Sn=9:1 electrode was higher than that of the two component electrode. The exact relationship between the removal of RhB and the generated oxidants concentration was not obvious. However, it was assumed that electrode with high RhB decolorization had high oxidant concentration.

The feasibility study of the application of the photoelectrocatalytic and electrolytic/UV decolorization of Rhodamine B (RhB) was investigated in the photoelectrocatalytic and electrolytic/UV process with TiO₂ photoelectrode and DSA (dimensionally stable anode) electrode. Three types of TiO₂ photoelectrode were used. Thermal oxidation electrode (Th-TiO₂) was made by oxidation of titanium metal sheet; sol-gel electrode (SG-TiO₂) and powder electrode (P-TiO₂) were made by coating and then heating a layer of titania sol-gel and slurry TiO₂ on titanium sheet. DSA electrodes were Ti and Ru/Ti electrode. The relative performance for RhB decolorization of each of the photoelectrodes and DSA electrodes is: Ru/Ti > Ti > SG-TiO₂ > Th-TiO₂. It was observed that photoelectrocatalytic decolorization of RhB is similar to the sum of the photocatalytic and electrolytic decolorization. Therefore the synergetic effect was not showed in pthotoelectrocatalytic reaction. Na₂SO₄ and NaCl showed different decolirization effect between pthotoelectrocatalytic and electrolytic/UV reaction. In the presence of the NaCl, RhB decolorization of Ru/Ti DSA electrode was higher than that of the other photoelectrode and Ti electrode. Optimum current, NaCl dosage and UV lamp power of the electrolytic/UV process (using Ru/Ti electrode) were 0.75 A, 0.5 g/L and 16 W, respectively.

피부에서 엘라스틴(elastin)은 중요한 탄력섬유의 구성성분 중의 하나이다. 피부주름(skin wrinkle) 형성은 콜라겐(collagen)의 합성과 분해가 중요한 요인으로 작용한다고 알려져 있지만, 최근 많은 연구에서 엘라스틴의 재형성과 분해 또한 주름형성 기전에서 중요한 작용을 하는 것으로 보고되고 있다. 엘라스타제(elastase)는 엘라스틴을 분해하는 일종의 메탈로프로테이나제(metalloproteinase)이며, 자외선 B (ultraviolet B, UVB) 조사 후에 활성이 증가하는 것으로 알려져 있다. 따라서 증가된 엘라스타제의 활성은 피부의 탄력성 감소와 주름 형성의 주요한 원인이 될 것이다. 본 연구에서는 항산화 효과가 있으며, 각종 견과류나 과일에 함유된 폴리페놀(polyphenol)성분인 탄닌산(tannic acid)을 사람의 섬유아세포(CCD-25Sk fibroblasts)에 처리하여 엘라스타제 활성과 트로포엘라스틴 생성에 미치는 영향을 조사하였다. 탄닌산은 농도의존적으로 사람의 섬유아세포 엘라스타제 활성을 유의성 있게 억제시켰다. 그러나 트로포엘라스틴 합성이나 발현증가에는 유의성 있는 효과를 보이지 않았다. 이러한 결과들로부터 탄닌산은 엘라스타제의 활성을 억제시켜 엘라스틴의 3차원적 구조를 유지하는데 기여하는 것으로 사료된다. 따라서 탄닌산은 주름생성을 억제하는 물질로 개발 가능할 것으로 기대된다.

This study was carried out to evaluate the effect of water quality of cooling tower on Legionella pneumophila disinfection using Ru/Ti electrode. The influences of parameters such as pH, turbidity, CaCO₃ and TOC were investigated using laboratory scale batch reactor. Oxidants such as free Cl, ClO₂, H₂O₂ and O₃ were measured. The results showed that all of the water quality parameters of cooling tower had deteriorated disinfection of Legionella pneumophila. When the turbidity, CaCO₃ and TOC was increased, oxidants which was generated during electrolysis was decreased. pH, free Cl, ClO₂ and H₂O₂ concentration were decreased with the increase of pH, whereas O₃ concentration was increased with the increase of pH. The order of effect of water quality on the disinfection performance for Legionella pneumophila was turbidity > CaCO₃ > TOC > pH. To obtain the safety standard (1000 CFU/L), the simultaneous increase current and NaCl dosage was needed.

The electro-chemical decolorization of Rhodamine B (RhB) in water has been carried out by electro Fenton-like process. The effect of distance, material and shape of electrode, NaCl concentration, current, electric power, H2O2 and pH have been studied. The results obtained that decrease of RhB concentration of Fe(+)-Fe(-) electrode system was higher than that of other electrode system. The decrease of RhB concentration was not affected electrode distance and shape. Decolorization of electro Fenton-like reaction, which was added H2O2 onto the electrolysis using electrode was higher than electrolysis. Addition of NaCl decreased the electric consumption. The lower pH is, the faster initial reaction rate and reaction termination time observed.

Small gas bubbles are used in many environmental and industrial processes for solid-liquid separations or to facilitate heat and mass transfer between phases. This study examines some of the factors that affect the bubble volume and size processed in the EF (electroflotation) process. The effect of electrode material, NaCl dosage, current and electrode distance were studied. The results showed that the generated bubble volume with electrode material lay in: Pt/Ti ≒ Ru/Ti ≒ Ir/Ti > Ti electrode. The more NaCl dosage was high, the smaller bubble was generated due to the low electric power. Bubble generation was increased with increase of current. With the increase of NaCl dosage, bubble generation was increased at same electric power (16.2 W). Generated bubble volume was not affected by electrode distance. However, no clear trends in bubble size as a function of these parameters were evident.

The performance of EF (electroflotation) on the thickening of activated sludge were investigated using laboratory scale batch flotation reactor. In this paper, the effects of parameters such as electrode material, NaCl dosage, initial sludge concentration and electrode distance were examined. The results showed that the performance for sludge thickening of the five electrodes lay in: Pt/Ti > Ru/Ti > Ir/Ti > Ti mesh > Ti plate. The more NaCl dosage was high, the more sludge was thickened and the shorter thickening time was obtained. However, considering the final thickening time and sludge concentration, optimum NaCl dosage was 0.5 g/L. Thickening time and sludge concentration was not affected by electrode distance. In DAF (dissolved air flotation) system, optimum recycle ratio was 40% and thickening performance was lower than that of the EF.

Laboratory scale experiments were conducted to investigate the removal characteristics of nitrogen and phosphorus in two sequencing batch biofilm reactors (SBBRs). SBBR1 had a short first non-aeration period and SBBR2 had a long first non-aeration period. The removal characteristics of nitrogen and phosphorus in each SBBR were precisely observed according to the variation of influent TOC concentration, and the operation control parameters (pH, DO concentration, ORP) in each reactor were measured. In biological nitrogen removal, there was little difference between SBBR1 and SBBR2 and the nitrogen removal efficiencies were very low. The nitrogen and phosphorus removal characteristics in high influent TOC concentration were different from those in low TOC. Nitrogen removals by simultaneous nitrification/denitrification (SND) were occurred in both SBBR1 and SBBR2. The P removal in SBBR1 was superior to that in SBBR2. The second P release was observed in SBBR1 which had long second non-aeration period.

This study was carried out to investigate the effect of electrochemical (EC) disinfection of artificial wastewater contaminated by Escherichia coli culture. Circulated batch type electrochemical disinfection system using three plates electrodes was used. Also, the several factors (pH, ORP, DO, temperature, current, conductivity) were measured in order to investigate the fundamental design factor in the EC disinfection system. It was demonstrated that the EC process was highly effective for wastewater disinfection. At the constant voltage, the disinfection efficiency was increased according to time. The disinfection efficiency and current increased as the increase of voltage. The variation of conductivity was a little related to the variation of CFU (colony forming units). The differences in disinfection efficiency according to the ice pack and the variation of electrodes were not occurred. The EC disinfection efficiency and current increased according to the increase of circulating flow rate.

The photocatalytic decolorization of Rhodamine B (RhB) was studied using packed-bed reactor and immobilized TiO2/UV System. The 20 W UV-A, UV-B and UV-C lamps were employed as the light source. The effect of shape and surface polishing extent of reflector, distance between the reactor and reflector, reactor material were investigated. The results showed that the order of the initial reaction constant with reflector shape was round > polygon > W > rhombus. The optimum distance between the reactor and reflector was 2 cm. The initial reaction constant of quartz reactor was 1.46 times higher than that of the PVDF reactor.

This study was carried out to investigate the variation of organic, nitrogen and phosphorus in (AO)2 SBBR process according to the variation of operating cycle at the high TOC concentration. The operation time in anoxic (anaerobic) time to oxic time was 1:1. Three lab-scale SBBRs were fed with synthetic wastewater based on glucose as carbon source. The variation of total TOC removal was similar each other irrespective of operation time, however, the TOC concentrations in SBBRs showed a little difference according to the operating condition. In SBBR, complete nitrification was not occurred at all reactors, however, R3 showed a higher nitrification than R2. And in SBBR, the variation of operating time more affected at phosphorus removal than nitrogen removal. R2 which had the shortest time at the 1st aeration time showed the lowest phosphorus release and uptake efficacy.

This study was carried out to evaluate effect of sludge characteristics (pH, SVI, anaerobic storage, wet density and growth phase) on the sedimentation of bulking sludge of paper manufacturing plant. The results showed that mix bulking sludge with sewage sludge (10-60%) caused the decrease of SVI, the settled sludge concentration was increased. Increase of anaerobic storage time (0 to 8 day) was increased SVI, sedimentation performance was deteriorated. The sedimentation was improved by addition of loess (0.2-5.0 g/L), because wet density of sludge was increased and SVI was decreased. At an exponential phase, the ratio of sedimented/growthed sludge concentration was decreased, the ratio was increased after stationary phase.

An effective technique of sludge separation is required for excess sludge of sewage or wastewater plant. The separation of bulking sludge of paper manufacturing plant was studied using DAF(Dissolved Air Flotation) system. The effects of parameters such as nozzle type, A/S(air/solid) ratio, pressure, injection time of pressured water and saturation time were examined. The results showed that the best nozzle type was flat which had small orifice hole. The optimum A/S ratio and pressure were 7.070×10-3(recycle ratio of pressured water : 20%) and 5 atm, respectively. Injection times of pressurized water around 20-25 sesc and flotation time of 30 min appeared to be optimal for the DAF operation. The order of performance of packing was 18 mm > 22 mm > 32 mm.

This study was carried out to get more operational characteristics of Anoxic(anaerobic)-Oxic-Anoxic-Oxic (AO)2 sequencing batch biofilm reactors (SBBRs) at the low TOC concentration. The operating time in anoxic (anaerobic) time to oxic time was 1：1. Experiments were conducted to find the effects of the aeration time distribution on the organic matters and nutrients removal. Three lab-scale reactors were fed with synthetic wastewater based on glucose as carbon source. During studies, the operation mode was fixed. The first aeration time to the second aeration time in SBBR-1 was 2：3, and those in SBBR-2 and SBBR-3 were 1：4 and 3：2, respectively. The organic removal efficiency didn't show large difference among three reactors of different aeration time distribution. However, from these study results, the optimum aeration time distribution in the first and the second aeration time for biological nutrient removal was shown as 3：2. The release of phosphorus was inhibited at the second non-aeration period because of the low TOC concentration and the nitrate produced by the nitrification at the first aeration period.

In order to know the effect of autoclaving on the heavy metal removal using chitosan, lead removal capacities and removal rates by various chitosans in aqueous solution were compared according to the various autoclaving time. The lead removal efficiencies and removal rates by the autoclaved chitosan were found to be on the order of 15 min(98%) 〉10 min(95%) 〉30 min(83%) 〉5 min(53%) 〉60 min(47%) 〉0 min(22%) chitosan. The molecular weight of chitosan was decreased by the increase of autoclaving time. Therefore, the heavy metal removal capacity was not well correlated to the molecular weight. Langmuir isotherm was well fitted to experimental results of equilibrium adsorption on chitosan. In order to examine the process of lead removal by the autoclaved chitosan, TEMs, SEMs and FT-IR analyses were used. The surface of autoclaved chitosan was much more porous and the lead removal was mainly occurred on the surface of chitosan. The structure of autoclaved chitosan was same as that of controlled chitosan.