Improved isolation of cadmium from paddy soil by novel technology based on pore water drainage with graphite-contained electro-kinetic geosynthetics

Tang, X; Li, Q; Wang, Z; Hu, Y; Hu, Y; Scholz, M

Abstract

Novel soil remediation equipment based on electro-kinetic geosynthetics (EKG) was developed for in situ isolation of metals from paddy soil. Two mutually independent field plot experiments A and B (with and without electric current applied) were conducted. After saturation using ferric chloride (FeCl3) and calcium chloride (CaCl2), soil water drainage capacity, soil cadmium (Cd) removal performance, energy consumption as well as soil residual of iron (Fe) and chloride (Cl) were assessed. Cadmium dissolved in the soil matrix and resulted in a 100% increase of diethylenetriamine-pentaacetic acid (DTPA) extracted phyto-available Cd. The total soil Cd content reductions were 15.20% and 26.58% for groups A and B, respectively, and electric field applications resulted in a 74.87% increase of soil total Cd removal. The electric energy consumption was only 2.17 kWh/m3 for group B. Drainage by gravity contributed to > 90% of the overall soil dewatering capacity. Compared to conventional electro-kinetic technology, excellent and fast soil water drainage resulted in negligible hydrogen ion (H+) and hydroxide ion (OH−) accumulation at nearby electrode zones, which addressed the challenge of anode corrosion and cathode precipitation of soil metals. External addition of FeCl3 and CaCl2 caused soil Fe and Cl residuals and led to 4.33–7.59% and 139–172% acceptable augments in soil total Fe and Cl content, correspondingly, if compared to original untreated soils. Therefore, the novel soil remediation equipment developed based on EKG can be regarded as a promising new in situ technology for thoroughly isolating metals from large-scale paddy soil fields.

Citation

Tang, X., Li, Q., Wang, Z., Hu, Y., Hu, Y., & Scholz, M. (2018). Improved isolation of cadmium from paddy soil by novel technology based on pore water drainage with graphite-contained electro-kinetic geosynthetics. Environmental Science and Pollution Research, 25(14), 14244-14253. https://doi.org/10.1007/s11356-018-1664-4

• Journal Article Type: Article
• Acceptance Date: Feb 28, 2018
• Online Publication Date: Mar 10, 2018
• Publication Date: Mar 10, 2018
• Deposit Date: May 23, 2018
• Publicly Available Date: May 23, 2018
• Journal: Environmental Science and Pollution Research
• Print ISSN: 0944-1344
• Publisher: Springer Verlag
• Volume: 25
• Issue: 14
• Pages: 14244-14253
• DOI: https://doi.org/10.1007/s11356-018-1664-4
• Keywords: Research Article, Anode corrosion and cathode precipitation prevention, Atmospheric acid deposition, Electric energy consumption, Environmental remediation technology, Hazardous material, Cadmium, Paddy soil remediation, Water drainage
• Publisher URL: https://doi.org/10.1007/s11356-018-1664-4
• Additional Information: Funders : Non-profit Industry Financial Project of MWR;Special Technical Innovation Project of Hubei Province;National Natural Science Foundation of China;Central Public-interest Scientific Institution Basal Research Fund; Grant Number: 201501019; Grant Number: 2017ABA073; Grant Number: 51409009; Grant Number: CKSF 2017047/SH