电气石对水体pH值的影响

Influence of tourmaline on pH value of water

用盐酸和氢氧化钠调节蒸馏水的pH值为3.2和12.12,加入电气石粉并搅拌,pH值趋向中性.10g电气石和10g花岗岩粉加入200mL蒸馏水中,搅拌1h,pH值分别变为8.57和8.89,用等离子谱(ICP)测得水中有Ca2+, Mg2+, Al3+, Fe2+,Fe3+, Mn3+, Cr3+, B3+, K+和Na+等.电气石处理的水中,除B3+之外其他离子浓度比花岗岩粉处理的低,说明电气石颗粒表面的离子交换吸附H+弱于花岗岩颗粒.在扫描电镜下发现电气石颗粒间彼此相依,存在吸引和排斥,而花岗岩颗粒间为团聚吸附,只有吸引.电气石颗粒的电极性影响水体的氧化还原电位,调节溶液pH值趋向中性;而表面吸附和离子交换吸附H+使酸性溶液pH值上升速率大于碱性溶液pH值下降速率.

The pH values of distilled water regulated with HCl and NaOH were 3.2 and 12.12, respectively. Then tourmaline powder was put into them and stirred; their pH values developed to the middle. 10g tourmaline and 10g granite powder were put into 200mL distilled water and stirred for 1h, and the pH values were 8.57 and 8.89, respectively. There were Ca2+, Mg2+, Al3+, Fe2+, Fe3+, Mn3+, Cr3+, B3+, K+ and Na+ dissolved into waters measured by inductively coupled argon plasma spectrometer (ICP). Their concentrations were lower in the water treated by tourmaline than by granite powder except B3+, which indicated the ability of ion exchange adsorption of H+ of tourmaline particles surface was weaker than that of granite. The SEM images show that attraction and repulsion exist among tourmaline particles, but no repulsion exists among the particles of granite, which conglomerate together. The electrode character of tourmaline particle influences the redox potential of waters and regulates the pH value of solution to the middle. Surface adsorption and ion exchange adsorption of H+ help the increase rate of pH value in acidic solution more than the decrease rate in basic solution.