Construction of a Self-Powered System for Simultaneous In Situ Remediation of Nitrate and Cr(VI) Contaminated Synthetic Groundwater and River Sediment

• Main Authors: Limei Han, Rui Liu, Miao Li, Ning Zhang, Fang Zhang, Xiang Liu
• Format: Article
• Language: English
• Published: MDPI AG 2018-08-01
• Series: Sustainability
• Subjects: self-powered system; groundwater remediation; denitrification; Cr(VI) removal; cyclic voltammetry (CV)
• Online Access: http://www.mdpi.com/2071-1050/10/8/2806

A novel self-powered system was constructed to in situ remove nitrate and Cr(VI) from synthetic groundwater and achieve river sediment remediation simultaneously. The sediment organic matter in an anodic chamber was used as a carbon source to provide self-powered energy to reduce the cathode’s contaminants. With the acceptance of protons and electrons, nitrate and Cr(VI) were transformed into nitrite and Cr(III), respectively. In a 72 h test with both nitrate and Cr(VI) present, nitrate was removed at a rate of 70.96 mg/m3·h and Cr(VI) at a rate of 8.95 mg/m3·h. When a phosphate buffer was used in the test, their removal rates were changed to 140.83 mg/m3·h and 8.33 mg/m3·h, respectively. The results showed that the self-powered system could achieve the simultaneous reduction of nitrate and Cr(VI), although the presence of Cr(VI) hindered nitrate reduction. This system could realize simultaneous in situ groundwater and sediment remediation, with no need for additional energy or materials.