研究台灣十五種土壤對重金屬之吸附實驗中,發現pH值為主要變因。土壤對金屬陽離子的吸附能力,隨著pH值增加而增加,六價鉻的吸附反應卻相反。除此之外,本計劃另一目的乃在檢視各種重金屬吸附與測得之土壤樣品的物理化學性質、有機質含量及金屬氧化物間之關係。模式無法成功的應用於土壤的自然pH值,因為金屬離子與氫離子(H/sup +/)彼此相互競爭土壤表面的吸附位置。然而在固定pH值下,土壤-重金屬之分配係數與有機質之間卻有相當高的關聯性。分配係數(Kd)經以有機質含量正規化(Normalization)之後所得的分配係數(Kom),與pH值間的相關性大為提高,如此說明了土壤性質中影響重金屬吸附最主要的成份應為有機質含量。 The metal adsorption characteristics of fifteen Taiwan soils, exemplified by Hg(II) Pb(II) and Cr(VI), were evaluated using pH as the major variable. The greater adsorption was found for soils with a higher organic matter content at constant pH and metal concentration. To better understand the mechanism of adsorption, the experimental results for Hg(II) Pb(II) and Cr(VI) were tested in a partition coefficient model to relate the adsorption of the metals by the different soils with soil components. Partition coefficients obtained from experimental data were highly correlated with those calculated for a partition coefficient between heavy metals and organic matter alone.
