低分子量有机酸对几种可变电荷土壤吸附氟的影响

用一次平衡法研究了四种低分子量有机酸对几种可变电荷土壤吸附氟的影响，结果表明，低分子量有机酸可以通过竞争吸附作用抑制土壤对氟的吸附，化学结构相对简单的草酸和丙二酸对氟吸附的抑制作用大于柠檬酸和苹果酸。有机酸对氟吸附的抑制作用随土壤氧化铁含量的增加而增加，并随体系pH的增加而增强。在低pH和氟加入量较高的情况下，有机酸通过与氟竞争可溶性铝而增加土壤对氟的吸附量，这在对铝溶解度较高的酸性土壤中尤为明显。

Effect of low-molecular-weight organic acids on the adsorption of fluoride on soils with variable charge

The effect of four low molecular weight organic acids on the adsorption of fluoride on soils with variable charge was investigated with a batch method. The results showed that organic acids reduced the adsorption of fluoride through competition with F - for sorption sites. The oxalic acid and malonic acid with simple chemical structure were more effective than citric acid and malic acid in reducing F - adsorption. The effect of organic acids on F - adsorption increased with the increase in pH. A higher content of iron oxides in soils led to more reduction in F - adsorption by organic acids. At low pH and with more fluoride added, existence of organic acids increased the adsorption of fluoride due to the competition of organic acids with F - for soluble Al and the increase of free fluoride in soil solution. This kind of effect mainly occurred in the soils with a higher solubility of Al.