Preparation of α-calcium sulfate hemihydrate whiskers with high aspect ratios in presence of a minor amount of CuCl_2·2H_2O

少量CuCl_2·2H_2O作用下制备高长径比α-半水硫酸钙晶须（英文）

In order to produceα-calcium sulfate hemihydrate(α-CaSO4·0.5H2O)whiskers with high aspect ratios,a minor amount of CuCl2·2H2O was used as the modifying agent in the process of hydrothermal treatment of calcium sulfate dihydrate(CaSO4·2H2O)precursor.The presence of 2.60×10–3 mol/L CuCl2·2H2O resulted in the increase of the aspect ratios ofα-CaSO4·0.5H2O whiskers from 81 to 253.The preferential adsorption of Cu2+on the negative{110}and{100}facets ofα-CaSO4·0.5H2O crystal structures was confirmed by EDS and XPS.And ATR-FTIR demonstrated the ligand adsorption of Cu2+on the surface ofα-CaSO4·0.5H2O whiskers.The experimental results reveal that the whiskers with high aspect ratios are attributed to the adsorption of Cu2+,which promotes the 1-D growth ofα-CaSO4·0.5H2O whiskers along the c axis.

为了制备高长径比的α-半水硫酸钙(α-CaSO_4·0.5H_2O)晶须,在以二水硫酸钙(CaSO_4·2H_2O)前驱体为原料的水热反应过程中加入CuCl_2·2H_2O作为媒晶剂。当反应体系中加入2.60×10–3 mol/L的CuCl_2·2H_2O时可以使产物α-半水硫酸钙晶须的长径比由81增加到253。EDS和XPS检测结果表明,CuCl_2·2H_2O能够显著增加α-半水硫酸钙晶须的长径比主要是因为Cu2+优先吸附于α-CaSO_4·0.5H_2O晶体带负电的{110}和{100}面,从而阻碍了侧面的生长,最终导致晶体长径比的增加。ATR-FTIR进一步证实了Cu2+主要通过配位吸附的形式与α-CaSO_4·0.5H_2O晶体表面进行作用。