The co-doping effect of aliovalent metal ions such as Mg2+, Ca2+, Sr2+, Ba2+, and Zn2+ on the photoluminescence of the Y2O3:Eu3+ red phosphor, prepared by spray pyrolysis, is analyzed. Mg2+ metal doping is found to be helpful for enhancing the luminescence of Y2O3:Eu3+. When comparing the luminescence intensity at the optimum doping level of each Mg2+ ion, the emission enhancement shows the order of Zn2+ Ba2+ > Ca2+ > Sr3+> Mg2+. The highest emission occurs when doping approximately 1.3% Zn2+, which is approximately 127% of the luminescence intensity of pure Y2O3:Eu3+. The highest emission was about 127% of the luminescence intensity of pure Y2O3:Eu3+ when doping about 1.3% Zn2+. It is determined that the reason (Y, M)2O3:Eu3+ has improved luminescence compared to that of Y2O3:Eu3+ is because the crystallinity of the matrix is improved and the non-luminous defects are reduced, even though local lattice strain is formed by the doping of aliovalent metal. Further improvement of the luminescence is achieved while reducing the particle size by using Li2CO3 as a flux with organic additives.

이 연구는 글리시딜 숙시네이트 양이온 제미니 계면활성제의 합성에 관한 것이다. 제미니 계면활성제는 2-메틸 디소디움 숙시네이트와 에피클로로히드린, N, N-디메틸 도데실 아민을 사용하여 합성하였다. FT-IR과 1H-NMR을 통해 물성을 확인하였다. 표면장력과 cmc 측정, 유화력 및 기포력을 각각 주어진 조건을 이용하여 측정하였다. 제미니 계면활성제의 표면장력은 33~34 dyne/cm이며 cmc 값은 10-4~10-3mol/L 였다. 제미니 계면활성제의 유화력은 유기용매에서 더 우수하였고 기포력이 안정한 것을 확인하였다.

The adsorption of lithium ion onto zeolite was investigated depending on contact time, initial concentration, cation forms, pH, and adsorption isotherms by employing batch adsorption experiment. The zeolite was converted into different forms such K+, Na+, Mg2+, Ca2+, and Al3+. The zeolite had the higher adsorption capacity of lithium ion in K+ form followed by Na+, Ca2+, Mg2+, and Al3+ forms, which was in accordance with their elctronegativities. The lithium ion adsorption was explained using the Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherms and kinetic models. Adsorption rate of lithium ion by zeolite modified in K+ form was controlled by pseudo-second-order and particle diffusion kinetic models. The maximum adsorption capacity obtained from Langmuir isotherm was 17.0 mg/g for zeolite modified in K+ form. The solution pH influenced significantly the lithium ions adsorption capacity and best results were obtained at pH 5-10.