Remediation of copper-contaminated farmland using waste lemon integrated with soil flushing and stabilization
| Autor: | Pei-Wen Zhang, 張沛文 |
|---|---|
| Rok vydání: | 2019 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 107 The soil of this study was taken from the No. 46 subsection of Kanjiao section, Zhuwei Vil., Dayuan Dist., Taoyuan City, which is a currently listed control site. The control standard of copper for edible crop agricultural land in Taiwan is 200 mg/kg, but the copper concentration of the soil in this study is as high as 2487 mg/kg, more than 10 times of the control standard. The purpose of this study is to investigate the effect of synthetic citric acid and the extract from the lemon extract on flushing heavy metal contaminated soil and to evaluate whether the soil quality meets every soil fertility standard after flushing citric acid and adding compost stabilization. The material prepared in this study is the lemon extract and the compost made from lemon extract of the remaining lemon. After broling the mixture of 1：1 weight ratio distilled water, the citric acid content is about 9.9 g/L. Therefore, chemical citric acid of 10 g / L concentration was used as the control group. After flushing soil with the flushing solution of 1：10 solid-liquid ratio, the result showed that the lemon extract has better flushing effect, and the factors contribute to this result are ( І ) Longer natural juice retention time (Ⅱ) Other elements(like flavonols) which can chelate heavy metal contained in lemon extract. The result proved that the soil after flushing lemon extract improve the soil acidification by flushing chemical citric acid and whether the added with compost stabilization after flushing lemon extract the soil met every soil fertility standard. The result showed that the pH of the original soil was 4.56 and the soil added with compost after flush with lemon extract could raise the pH to 6.29 and effectively drop copper plant effectiveness; the plant effectiveness of the heavy metal copper in the original soil is 677 mg/kg, and the soil with compost stabilization after flushing lemon extract can decrease the plant effectiveness of heavy metal copper to 156 mg/kg. In summary, this study proved that using lemon extract not only effectively removed heavy metal with better effect than the chemical citric acid, but also improve the acidification of soil through chemical citric acid addition. Moreover, adding compost can passivate heavy metal not to be easily released. Therefore, the combination of citric acid flushing method and stabilization method is an effective remediation method. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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