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생물여과반응기에서 폐가스의 VOC 제거에 대한 전자수용체의 영향
백병천,Xueqing Zhu 國立 麗水大學校 環境問題硏究所 1998 環境硏究論文集 Vol.1 No.-
Biofiltration is fast becoming the technology of choice for the control of the volatile organic compounds (VOCs) present in air streams due to its cost-effectiveness. This study was carried out to investigate the effect of electron acceptors on the performance of biofiltration process treating diethyl ether as a VOC substrate in waste gases. Two trickle bed biofilters with pelletized synthetic media were operated co-currently at a empty bed hydraulic retention time of 25 seconds, inlet gas flow rate of 8.64㎥/day, Nutrient liquid flowrate of 1L/day, and COD loading rate from 1.8 to 7.1㎏ COD/㎥.day. Nitrate and oxygen were used as the electron acceptor for the VOC (ether) biodegradation. By increasing the concentration of oxygen in the feed to this biofilter from 21% (ambient air) to 50% and 100% while maintaining an influent VOC (ether) concentration of 133 ppm_(v) and a feed nitrate concentration of 67㎎/ℓ, the performance of the biofilter was not significantly affected. However, the VOC (ether) removal efficiencies improved with increasing influent nitrate concentration. which suggest that nitrate is a good electron acceptor more than oxygen. It was also found that nitrate was rate limiting as a growth nutrient rather than as an electron acceptor, and that resistance to the transport of nitrate into the biofilm led to nutrient limitations in the deeper layers of the biofilm.
Low-Temperature Synthesis of Highly Efficient, Deep-Red Zn-Cu-In-Se/ZnSe Fluorescence Quantum Dots
Juan Yang,Jingling Li,Yanqing Zhu,Xueqing Xu,Xiudi Xiao,Bing Deng,Kaili Qin,Zhuoneng Bi,Shuaijun Chen,Gang Xu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.6
We report a facile synthesis method on CuInSe2 (CISe)-based quantum dots (QDs) by using tri-n-octylphosphine selenium (TOPSe) as selenide precursor, with assistance of oleylamine (OAm) and n-dodecanethiol (DDT). We demonstrate that the OAm and DDT jointly contribute to the formation of the low-temperature-decomposable metal-sulfide clusters, and promote the QD nucleation at relatively low temperature range of 180–200 ℃. Furthermore, to improve fluorescence property, Zn-doping and ZnSe coating are simultaneously carried out. The obtained deep-red ZnCISe/ZnSe QDs possess higher quantum yield of 65% at wavelength of 670 nm, which is in the best performance range ever reported. Then, we investigate the improvement mechanism, where the sufficient Zn replacement of In sites is the crucial factor. This modified core–shell structure provides two benefits, on the one hand, the enhancement on intrinsic defect-related recombination, and the other hand, the improved core–shell interface that reduces the nonradiative recombination.
Kaili Qin,Jingling Li,Yanqing Zhu,Xueqing Xu,Xiudi Xiao,Bing Deng,Juan Yang,Zhuoneng Bi,Shuaijun Chen,Gang Xu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.8
Crystal structure control is so important to the fluorescence properties that each element should be considered carefully. In conventional synthesis of ZnxCd1-xS alloyed nanocrystals (NCs), most of studies focus on ligand–surface interaction on the formation of either zinc blende or wurtzite ZnxCd1-xS nanocrystals, instead of the reactant source. In this work, mixed crystal phase was found easily in ZnxCd1-xS alloyed NCs when reaction proceeded at high Zn/Cd source ratio condition. Therefore, we regulate the Zn/Cd ratio to obtain relative pure zinc-blende structure, and study the influence of structure change on the fluorescence properties. Further, we have proposed a two-step ZnS coating method to acquire ZnxCd1-xS/ZnS NCs with separated crystal-phase between core and shell. Compared with maximum QY of 81% for ZnxCd1-xS/ZnS NCs synthesized by conventional one-step coating method, the performance of the optimized NCs has significantly improved with maximum QY of 93%.