화학공학소재연구정보센터
Journal of Physical Chemistry A, Vol.115, No.22, 5540-5546, 2011
Raman Spectroscopic Study of Crystallization from Solutions Containing MgSO4 and Na2SO4: Raman Spectra of Double Salts
Mg2+, Na+, and SO42- are common ions in natural systems, and they are usually found in water bodies. Precipitation processes have great importance in environmental studies because they may be part of complex natural cycles; natural formation of atmospheric particulate matter is just one case. In this work, Na2Mg(SO4)(2)center dot 5H(2)O (konyaite), Na6Mg(SO4)(4) (vanthoffite), and Na12Mg7(SO4)(13)center dot 15H(2)O (loeweite) were synthesized and their Raman spectra reported. By slow vaporization (at 20 degrees C and relative humidity of 60-70%), crystallization experiments were performed within small droplets (diameter <= 1-2 mm) of solutions containing MgSO4 and Na2SO4, and crystal formations were studied by Raman spectroscopy. Crystallization of Na2Mg(SO4)(2)center dot 4H(2)O (bloedite) was observed, and the formation of salt mixtures was confirmed by Raman spectra. Bloedite, konyaite, and loeweite, as well as Na2SO4 and MgSO4 center dot 6H(2)O, were the components found to occur in different proportions. No crystallization of Na6Mg(SO4)(4) (vanthoffite) was observed under the crystallization condition used in this study.