離子交換樹脂測定水飽和土壤之重金屬生物有效性

Investigation on Heavy Metal Bioavailability of Saturated Soil by Ion Exchange

賴旭亮(Lai Shiuh Liang)

指導教授 ： 林勝雄

元智大學/工程學院/化學工程與材料科學學系/碩士(1997年)

摘要

金屬污染物進入土壤後，受到土壤的吸附作用，而以各種型態存
在於土壤之中，然而金屬污染物的化學性質及土壤環境條件(如酸鹼
度)的改變，會影響土壤對金屬污染物的吸附，進而干擾到金屬離子
在土壤中的傳輸，而使金屬生物有效性產生變化。

本文以兩種不同的土壤對四種不同重金屬之吸附作用的研究，發
現土壤種類不同及重金屬種類不同，其吸附特性亦異。土壤種類間對
金屬的吸附作用影響差異較小，不同金屬間的差異較大。實驗結果也
發現，pH值對其影響也很大。

影響土壤中重金屬生物有效性的因素有土壤種類、土壤pH值、土
壤中重金屬污染物的量、金屬種類等。其中可以得知當土壤pH值愈低
、未被吸附的重金屬污染物濃度愈高，金屬的生物有效性愈高；金屬
和土壤種類不同，金屬的生物有效性亦異。而且重金屬的生物有效性
，與土壤的吸附作用有一定的相關性。

金屬在水飽和土壤中的擴散行為中，利用離子交換樹脂作為一個
無限匯池(Infinite Sink) ，以數學邊界條件求得擴散係數(Diffusion
Coefficient) ，進而了解金屬在土壤的擴散係數，僅受溫度和金屬
種類的影響。

關鍵字

重金屬 ； 生物有效性 ； 有效擴散係數 ； 土壤 ； 土壤吸附 ； 酸鹼度 ； 離子交換樹脂

並列摘要

When heavy metal is present in soils, it gets adsorbed and
exists in various forms in those soils. However, the chemical
properties of heavy metal and soil properties will strongly
affect the heavy metal adsorption. They also considerably
influence the transport of heavy metal in soils and thus
the heavy metal bioavailability.

In the present study, experimental investigations were
conducted to examine the adsorption characteristics and
bioavailabilities of four heavy metals in two different
types of soils. The test results have demonstrated that
the adsorption and bioavailabilities are more strongly
affected by the different type of heavy metal than the
soil type and conditions(i.e. pH). It was also observed
that the bioavailability of a given heavy metal metal
increases with an increase in heavy metal concentration
in soils and a decrease in soil pH.

A diffusion model based on the Fick*s law was utilized to
simulate the heavy metal transport in soils with ion exchange
resin as an infinite sink. The mathematical model allowed
easy determination of the effective diffusion of heavy metal
which is strongly related to the bioavailability of this
heavy metal. The effective coefficient was experimentally
observed to vary with the operating temperature and type of
heavy metal under investigation.

並列關鍵字

Heavy Metal ； Bioavailability ； Effective Diffusion Coefficient ； Soil ； Soil Adsorption ； pH ； Ion Exchange

參考文獻

環保署，"台灣地區土壤重金屬含量調查報告" ，行政院環保署(1989)

Abrams, M. M. and Jarrell, W. M., "Bioavailability Index for Phosphorus Using Ion Exchange Resin Impregnated Membranes", Soil Science Society of America Journal, 56, 1532 (1992)

Alloway, B. J., "Cadmium", in Heavy Metals in Soils., Blackie Publishers, London, UK., 100 (1990)

Amer, F., Bouldin, D. R., Black, C. A. and Duke, F. R.﹐"Chacterization of Soil Phosphorus by Anion Exchange Resin Adsorption and P32- Equilibration"﹐Plant and Soil, 6, 399 (1955)

Crank, J., "The Mathematics of Diffusion", 2nd ed., Oxford, London (1975)