레이져를 이용한 도핑 특성과 선택적 도핑 에미터 실리콘 태양전지의 제작

박성은(Sungeun Park),박효민(Hyomin Park),남정규(Junggyu Nam),양정엽(JungYup Yang),이동호(Dongho Lee),민병권(Byoung Koun Min),김경남(Kyung Nam Kim),박세진(Se Jin Park),이해석(Hae-Seok Lee),김동환(Donghwan Kim),강윤묵(Yoonmook Kang),김동 한국태양광발전학회 2016 Current Photovoltaic Research Vol.4 No.2

Laser-doped selective emitter process requires dopant source deposition, spin-on-glass, and is able to form selective emitter through SiNx layer by laser irradiation on desired locations. However, after laser doping process, the remaining dopant layer needs to be washed out. Laser-induced melting of pre-deposited impurity doping is a precise selective doping method minimizing addition of process steps. In this study, we introduce a novel scheme for fabricating highly efficient selective emitter solar cell by laser doping. During this process, laser induced damage induces front contact destabilization due to the hindrance of silver nucleation even though laser doping has a potential of commercialization with simple process concept. When the laser induced damage is effectively removed using solution etch back process, the disadvantage of laser doping was effectively removed. The devices fabricated using laser doping scheme power conversion efficiency was significantly improved about 1% abs. after removal the laser damages.

Selective Catalyst Reduction of NOx in a Dielectric Barrier Discharge Reactor: Effects of Hydrocarbons

( Nguyen Duc Ba ),( Nguyen Van Toan ),목영선 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

Ag/Al₂O₃ catalyst with hydrocarbons as a reduction agent is potential for selective catalyst reduction of NOx at a temperature above 300°C. However, NOx efficiency removal decreased sharply at an early state or low temperature, owing to the low activity of hydrocarbon reducing agent at low-temperatures (≤ 250°C). In order to expended temperature window, a combination of the catalyst with atmospheric-pressure plasma has been proposed, since plasma-catalyst enhanced partially oxidize hydrocarbons at low temperature and these hydrocarbon derivatives are more activity for NOx removal. In this work, several hydrocarbons such as C₂H₄, C₃H₈, and C₇H₁₆ have been proposed as a reducing agent for the process. The effects will consider in terms of NOx efficiency removal, energy efficiency, and hydrocarbon consumption.

Reuse of municipal wastewater via membrane capacitive deionization using ion-selective polymer-coated carbon electrodes in pilot-scale

Kim, David Inhyuk,Dorji, Pema,Gwak, Gimun,Phuntsho, Sherub,Hong, Seungkwan,Shon, Hokyong Elsevier 2019 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.372 No.-

<P><B>Abstract</B></P> <P>This study investigated membrane capacitive deionization (MCDI) at a pilot-scale using ion-selective polymer-coated carbon electrodes for wastewater reuse. Several issues have been addressed to verify the suitability of MCDI for wastewater reclamation: electrosorption performance, removal efficiency and selectivity of ions present in wastewater, optimization of operating conditions, and performance degradation in long-term caused by the accumulation of organic contaminants. The coated electrodes had better adsorption capacities and charge efficiencies than the conventional MCDI system, which was attributed to their low electrical resistance induced by the thin coated layer. The pilot-scale MCDI test cell involved 50 pairs of anion- and cation-selective electrodes and achieved good removal efficiency of ions from the wastewater effluent, particularly for problematic charged impurities, such as nitrate (NO<SUB>3</SUB> <SUP>−</SUP>) (up to 91.08% of NO<SUB>3</SUB> <SUP>−</SUP> was removed). Increasing the flow rate and reducing the applied potential were shown to be efficient for achieving better water quality by enhancing the NO<SUB>3</SUB> <SUP>−</SUP> selectivity. Last, the 15 d operation showed good reproducibility in electrosorption and regeneration for the coated electrodes, despite the fact that high concentrations of organics were contained in the wastewater feed solution (12.4 mg/L of dissolved organic carbon).</P> <P><B>Highlights</B></P> <P> <UL> <LI> MCDI was probed for wastewater reuse in pilot-scale using ion selective electrodes. </LI> <LI> The coated electrodes showed better performance attributing to its low resistivity. </LI> <LI> NO<SUB>3</SUB> <SUP>−</SUP> was selectively removed attributing to its high permselectivity through AEM. </LI> <LI> Faster flow rate and lower potential enhanced NO<SUB>3</SUB> <SUP>−</SUP> selectivity in single-pass mode. </LI> <LI> The flat coated layer kept organic substances from accumulating on the surface. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Mixed metal oxide coated polymer beads for enhanced phosphorus removal from membrane bioreactor effluents

Park, Hak-Soon,Kwak, Se-Hoon,Mahardika, Dedy,Mameda, Naresh,Choo, Kwang-Ho Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.319 No.-

<P><B>Abstract</B></P> <P>Membrane bioreactors are effective and attractive for wastewater reclamation and reuse, but phosphorus polishing is required to meet more stringent environmental regulations. Mixed metal oxide coated beads composed of Fe-Ti bimetal oxides on a sulfonated polymer were fabricated, characterized, and tested for phosphorus removal from membrane bioreactor effluents. Ti doping substantially enhanced the adsorption rate and capacity of the coated beads, possibly due to more positively charged surfaces. The mixed metal oxide coated beads were highly selective to phosphate ions (selectivity factor >25) against background ions (e.g., Cl<SUP>−</SUP>, NO<SUB>3</SUB> <SUP>−</SUP>, and SO<SUB>4</SUB> <SUP>2−</SUP>), although they were less selective against bicarbonate and organics. Regenerated beads showed greater adsorption performance than the virgin ones. Ca binding to mixed metal oxide layers was responsible for enhanced phosphorus sorption, presumably resulting from the formation of calcium phosphate. The phosphorus recovery from the exhausted column adsorber was successful with alkaline solution (e.g., >90% P was recovered at a NaOH load of 0.2eq/L bed. Using mixed metal oxide chemically anchored on polymer beads for phosphorus sorption would be a promising complement to biological phosphorus removal.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fe-Ti bimetal oxide-coated composite beads were investigated for phosphorus removal. </LI> <LI> A small amount of Ti dopant enhanced phosphorus removal significantly. </LI> <LI> Phosphate selectivity was remarkable against common background anions. </LI> <LI> Ca binding to the coated bead improved phosphate sorption. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

끽다거(喫茶去)의 사상적 연원 ‘유혐간택(唯嫌揀擇)’

정순일(SunIl Jeong) 한국차학회 2016 한국차학회지 Vol.22 No.2

To Chao-Chou, a famous dharma master, the commonality between preaching Buddha's teaching and having a cup of tea was the removal of selection, which became the philosophical foundation of the one-taste of truth and seon (zen; ch'en). The greatest encumbrance in ch'en(zen) philosophy is the dualistic thought dividing subject and object and the mind differentiating this from that. Selection comes from differentiating things and in sentient beings this becomes the very obstacle to attaining Buddhahood. The 3rd dharma master of Chinese seon (zen) Buddhism, Seng-ts'an, said that “the ultimate tao (path) is not difficult, but will be achievable only if you avoid selection”, and Chao-Chou faithfully conformed to his saying. If we change the subject matter in his teaching of ‘avoidance of selection’ into tea, it can be expressed as ‘having a cup of tea.’ The most important point in the expression, “having a cup of tea”, is not the tea itself or the person having tea, but throwing the selection away. This is the philosophical core of he Chinese seon (zen) Buddhism tradition and also the philosophical core of the “one taste of tea and seon (zen)”.

Ultra-trace copper(II) detection and removal from wastewater using novel meso-adsorbent

Md. Rabiul Awual,Mohamed Ismael,Md. Abdul Khaleque,Tsuyoshi Yaita 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

The functionalized mesoporous silica based meso-adsorbent was developed for ultra-trace Cu(II) detection and removal from wastewater. The meso-adsorbent was fabricated by direct immobilization of N,N-bis(salicylidene)1,2-bis(2-aminophenylthio)ethane onto mesoporous silica monoliths. The calcu-lated HOMO–LUMO small energy gap suggested that the electrons excitation according to the electron/energy transfer mechanism was evident in the intense of color complexation during selective detection and removal. The adsorbent was successfully applied in the determination and removal of Cu(II) ions in environmental samples. Therefore, the meso-adsorbent has been shown to have the potential to be used as an effective adsorbent for trace Cu(II) capturing from wastewater.

Synthesis of core–shell magnetic adsorbent nanoparticle and selectivity analysis for binary system dye removal

Niyaz Mohammad Mahmoodi 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

Core–shell magnetic adsorbent nanoparticle (CSMAN) was synthesized and used to remove dye from binary system. The characteristics of CSMAN were investigated using FTIR and SEM. Acid Red 18 (AR18), Direct Green 6 (DG6) and Direct Red 31 (DR31) were used. The effect of adsorbent dosage, dye concentration and salt on dye removal was evaluated. Kinetic and isotherm of dye adsorption followed pseudo-second order and Langmuir isotherm, respectively. The maximum dye adsorption capacity (Q0) was 588, 333 and 323 mg/g for AR18, DG6 and DR31, respectively. Selectivity analysis for binary system showed that the magnetic adsorbent had no selectivity.

Development of nanoscale zirconium molybdate embedded anion exchange resin for selective removal of phosphate

Bui, Trung Huu,Hong, Sung Pil,Yoon, Jeyong Elsevier 2018 Water research Vol.134 No.-

<P><B>Abstract</B></P> <P>Development of a selective adsorbent with an enhanced removal efficiency for phosphate from wastewater is urgently needed. Here, a hybrid adsorbent of nanoscale zirconium molybdate embedded in a macroporous anion exchange resin (ZMAE) is proposed for the selective removal of phosphate. The ZMAE consists of a low agglomeration of zirconium molybdate nanoparticles (ZM NPs) dispersed within the structure of the anion exchange (AE) resin. As major results, the phosphate adsorption capacity of the ZMAE (26.1 mg-P/g) in the presence of excess sulfate (5 mM) is superior to that of the pristine AE resin (1.8 mg-P/g) although their phosphate uptake capacity was similar in the absence of sulfate and these results were supported by the high selectivity coefficient of the ZMAE toward phosphate over sulfate (S<SUB>PO4/SO4</SUB>) more than 100 times compared to the pristine AE resin. This superior selective performance of the ZMAE for phosphate in the presence of sulfate ions is well explained by the role of the ZM NPs that contributed to 69% of the phosphate capacity which is based on an observation that the phosphate adsorption capacity of the ZM NPs is not affected by the presence of sulfate. In addition, the behavior of the selective phosphate removal by the ZMAE was well demonstrated by not only in the batch mode experiment with simulated Mekong river water and representative wastewater effluent but also in a column test.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A hybrid ZMAE as a selective phosphate adsorbent was successfully developed. </LI> <LI> The ZMAE showed much superior phosphate efficiency and selectivity than the AE resin. </LI> <LI> This great performance of the ZMAE was attributed to the role of ZM nanoparticles. </LI> <LI> The phosphate selective contribution of the ZMAE was analyzed and discussed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

BaO가 담지된 V2O5-WO3/TiO2 SCR 촉매의 질소산화물 흡, 탈착 특성 및 제거 효율

김진우,예보라,이민우,정보라,이덕현,이희수,김홍대 대한금속·재료학회 2019 대한금속·재료학회지 Vol.57 No.4

Recently, directly emitted NOx upon start-up has been spotlighted as a significant emissions problem. BaO loaded V2O5-WO3/TiO2 Selective Catalytic Reduction (SCR) catalysts were synthesized with various contents of barium which was a representative NOx adsorbent and their NOx adsorption, desorption, and removal efficiency were shown. The phase of BaO was changed to a BaO or BaCO3 phase, which is capable of NOx adsorption when loaded on the TiO2 support. The more BaO contents were increased, the higher the intensity of Ba2+, the NOx adsorption site, measured by FT-IR. Also, NOx storage capacities of the BaO loaded catalysts, which contained 5 wt% and 10 wt% of BaO, were calculated to be 12.59 μmol/g and 20.21 μmol/g at 200 °C respectively. The improvement in NOx storage capacity was explained by the increase in BaO content. And then the BaO loaded catalyst desorbed NOx in the temperature range of 345 to 360 °C, which was the catalyst operating temperature. The NOx removal efficiency increased by reducing BaO content, and the catalyst loaded with 3 wt% of BaO showed 98% NOx removal efficiency at 350 °C. The adsorbed NOx at 200 °C was desorbed at 300~400 °C and then removed by the SCR reaction. The synthesized NOx trap functional SCR catalyst can be applied to reduce the NOx generated at the time of equipment start-up at low temperatures.

Effects of side-stream, low temperature phosphorus recovery on the performance of anaerobic/anoxic/oxic systems integrated with sludge pretreatment

Raj, S.E.,Banu, J.R.,Kaliappan, S.,Yeom, I.T.,Adish Kumar, S. Elsevier Applied Science 2013 Bioresource Technology Vol.140 No.-

Introduction of sludge reduction practices in enhanced biological phosphate removal (EBPR) often leads to a decrease in phosphorous (P) removal efficiency. In this study, an attempt has been made to develop sustainable P removal in an anaerobic/anoxic/oxic (AAO) system integrated with sludge reduction by incorporating side-stream P recovery. Two AAO reactors, one acting as a control (CAAO) and the other as an experimental system (EAAO), were used in our experiment. The average P solubilisation efficiency and its recovery from thermally pre-treated sludge were found to be 28% and 99%, respectively. The P recovery process prevented the biomass in the EAAO system from reaching its threshold level and resulted in sustainable P removal throughout the study period. Thermochemical pre-treatment, at a rate of 1.5% Q in the EAAO reactor, was responsible for a 28% reduction in the amount of sludge produced. The yield observed (Y<SUB>obs</SUB>) values for the system with and without pre-treatment were found to be 0.28 and 0.22kg MLSS/kg COD, respectively. An initial 50days of reactor operation was utilised to stabilise the systems (Phase 1). The total nitrogen removal during Phase 2 (51-225days) was slightly higher than that in Phase 1 (76-80% and 68-75%, respectively). The MLSS/MLVSS ratios of both systems were identical and were between 78% and 83% for both the CAAO and EAAO. The effluent COD concentration was not significantly affected by the proposed method of treatment. From the results of the present study, it is concluded that the proposed mode of treatment was capable of both sustainable removal of P and control of excess sludge production.