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在中性条件下,低浓度的柠檬酸、草酸、酒石酸和胡敏酸阴离子都能显著降低针铁矿、非晶氧化铝、高岭石和红壤对磷酸根的吸附,尤其在低磷吸附饱和度下效果更好。有机阴离子抑制磷酸根吸附的能力因有机酸的种类和性质、以及固相的表面特性而异。有机阴离子存在下吸附的磷酸根具有较高的同位素~(32)P交换活性和解吸率。测定了吸附平衡溶液中铁和铝的浓度。结果表明,在实验条件下(pH 7.0),即使较高浓度的有机酸根(10~(-2)mol)也只能溶解极少量的铁和铝。有机阴离子络溶作用不足以说明固相吸附磷能力的显著下降。可见,有机阴离子降低磷酸根吸附的机制主要是竞争专性吸附。有机阴离子占据了一部分高亲和力的吸附位,从而降低了土壤固相吸附磷的量,增加了吸附态磷的活性。
Under neutral conditions, low concentration of citric acid, oxalic acid, tartaric acid and humic acid anions can significantly reduce the phosphate adsorption of goethite, amorphous alumina, kaolinite and red soil, especially in the low phosphorus adsorption saturation Under the effect better. The ability of organic anions to inhibit phosphate adsorption varies depending on the type and nature of the organic acid, as well as the surface characteristics of the solid phase. The presence of organic anions adsorbed phosphate has a higher isotope ~ (32) P exchange activity and desorption rate. The concentration of iron and aluminum in the equilibrium solution of adsorption was measured. The results showed that under the experimental conditions (pH 7.0), only a very small amount of iron and aluminum could be dissolved even with higher concentrations of organic acid radicals (10 -2 mol). Organic anion solubilization is not sufficient to demonstrate a significant drop in the ability of the solid phase to adsorb phosphorus. It can be seen that the mechanism by which organic anions reduce phosphate adsorption is mainly competitive adsorption. Organic anions occupy part of the high affinity adsorption sites, thus reducing the amount of soil solid-phase adsorption of phosphorus, increasing the adsorption of phosphorus activity.