Zhou Chun Hui,Xia Shu Ting,Komarneni Sridhar,Kabwe Freeman Bwalya,Jin Gui Chen,Chu Mao Quan
Dolomite is an abundant, naturally occurring carbonate mineral, but the conventional processes of converting dolomite to new materials are time-consuming and energy-intensive. In addition, products from dolomite such as magnesium oxide, magnesium carbonate, magnesium hydroxide, which are used as adsorbents and additives, are mostly low value-added. Here, we demonstrated the conversion of dolomite to a mesoporous calcium-magnesium silicate (m-CMS) using a green and efficient continuous-flow synthesis method. The samples were characterized using powder X-ray diffraction, Fourier transformed infrared spectroscopy, N 2 adsorption/desorption isotherms, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. The material possessed mesoporosity and exhibited high a specific surface area of 629 m 2 /g and a pore volume of 0.66 cm 3 /g. The maximum water absorptivity of the sample was 52.6%. After the m-CMS immersing in Tris–HCl solution for 56 days, the weight loss ratio reached 30 wt%, indicating its good potential biodegradability. Hydroxyapatite was formed on the surfaces after the m-CMS was immersed in simulated body fluids. The m-CSM provided nucleation sites, and subsequently supplied Ca 2+ for hydroxyapatite crystal growth, indicating that the material has potential bone conduction capability. This work suggests that m-CMS can be synthesized from dolomite and tetraethyl orthosilicate through a quick continuous process, and that the m-CMS could be used as a biomaterial.
Xiangyang Liu,Tian Lan,Chengjie Wang,Manh Quang Nguyen,Ying Zhang,Maogang He
Tert-butanol is a good additive for improving gasoline performance, but as two of the most important thermodynamic properties, the critical temperature ( T c ) and critical pressure ( p c ) of tert-butanol and alkane systems have not been studied. In this work, the experimental data of the T c and p c of five binary systems (tert-butanol + cyclohexane , tert-butanol + n-hexane, tert-butanol + n-heptane, tert-butanol + n-octane, and tert-butanol + n-nonane) and a ternary system (tert-butanol + n-heptane + n-octane) were obtained using a flow method. The T c and p c of the binary systems were fitted using the Redlich–Kister equations with maximum average absolute relative deviations (AARDs) of 0.19% and 0.36% for T c and p c , respectively. The T c and p c for tert-butanol + n-heptane + n-octane were correlated by Singh and Sharma's equations and Cibulka's equations with AARDs less than 0.09% and 0.32%, respectively. The experimental data of T c and p c were also used to verify and improve the accuracy of our previous prediction model.
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