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| Optimizing the formulation and stabilization effects of an amendment for cadmium and arsenic contaminated soil |
| Received:June 04, 2019 |
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| KeyWord:cadmium;arsenic;biochar;sepiolite;vermiculite;optimal formulation |
| Author Name | Affiliation | E-mail | | XIONG Jing | National Engineering Laboratory for Site Remediation Technologies, Beijing 100015, China | | | GUO Li-li | National Engineering Laboratory for Site Remediation Technologies, Beijing 100015, China | | | LI Shu-peng | National Engineering Laboratory for Site Remediation Technologies, Beijing 100015, China | | | LIN Qi-mei | College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China | | | CHEN You-jian | National Engineering Laboratory for Site Remediation Technologies, Beijing 100015, China | chenyoujian@bceer.com |
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| Abstract: |
| To select suitable amendments for soil polluted with cadmium and arsenic, the D-optimal mixture design method was used to find an optimum formula of modified biochar, sepiolite, and vermiculite for cadmium and arsenic stabilization. Compared to biochar, the capacity of FeCl3-modified biochar to absorb As increased but decreased for Cd. Compared to sepiolite or vermiculite, the capacity of acidmodified sepiolite or vermiculite to absorb As increased but remained unchanged for Cd. FeCl3-modified biochar combined with acid-modified sepiolite and acid-modified vermiculite could effectively reduce the content of Cd and As available in soil. The available Cd was transformed into a residual form whereas the available As was transformed into organic matter and residual forms. The statistical software Design Expert was used to analyze the data and a regression model was established for the available Cd and As parameters. Based on a complete consideration of these parameters, an optimal amendment formulation was found consisting of 26.97% FeCl3-modified biochar, 23.49% acid-modified sepiolite, and 49.54% acid-modified vermiculite. When added amendments with the optimized formulation, the actual available Cd and As of soil were 0.97 mg·kg-1 and 0.26 mg·kg-1, respectively, which closely approximated their predicted counterparts. The results indicated that the combination of FeCl3-modified biochar and acid-modified sepiolite and vermiculite could effectively reduce the bioavailability of Cd and As in soil. |
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