天水大气降尘矿物与水作用产生羟基自由基研究

Research on aqueous hydroxyl radical generated from minerals of dust fall in Tianshui

利用高效液相色谱法测定了甘肃天水市麦积镇降尘与水作用产生羟基自由基(?OH)的能力,并根据降尘中主要矿物的百分含量对降尘与水作用产生?OH进行理论和混合模拟.结果表明,天水降尘中的主要矿物组成为石英,方解石,钠长石,白云母.降尘及组成矿物成分与模拟降尘与水作用产生?OH能力大小顺序为:方解石(1.30×10^(-10)mol)>理论模拟降尘(5.47×10^(-11)mol)>降尘(5.34×10^(-11)mol)>石英(2.90×10^(-11)mol)>白云母(1.90×10^(-11)mol)>钠长石(1.09×10^(-11)mol)>混合模拟降尘(7.16×10^(-12)mol).降尘中的矿物成分是降尘与水作用产生?OH的主要贡献者.降尘中矿物的组成和在水溶液中金属离子与有机物的溶出,降尘与水作用时的接触表面积,矿物组分之间水溶液中的相互作用,可能是导致降尘,混合模拟降尘,理论模拟降尘三者与水作用产生?OH量有所差异的原因.

The generation of aqueous hydroxyl radical from the dust fall, collected from Tianshui City, Gansu province, was investigated using the high performance liquid chromatography method. The mineral composition of dust fall was quartz（57.08%）, calcite（27.79%）, albite（10.29%）, and muscovite（4.84%）. The amount of generated hydroxyl radical from dust fall, simulated dust fall（including theoretical calculation method and physical mix method）, and pure minerals were in the following order： calcite（1.30×10^-10ol） 〉simulated dust fall（calculation）（5.47×10^-11ol） 〉dust fall（5.34×10^-11ol） quartz（2.90×10^-11ol） 〉muscovite（1.90×10^-11ol） albite（1.09×10^-11ol） dust fall（mix）（7.16×10^-12mol）. The minerals in dust fall had the major contribution to the formation of hydroxyl radical. The discrepancy in the amount of the generated hydroxyl radical between dust fall and simulated dust fall was caused by mineral composition, the dissolution of metallic ions and organic compounds in water, the surface area of minerals, and the interactions between the mineral and the water media.