Electrokinetic enhancement removal of heavy metals from industrial wastewater sludge

An enhanced electrokinetic process for removal of metals (Cr, Cu, Fe, Ni, Pb, Zn) from an industrial wastewater sludge was performed. The electrokinetic experiments were conducted under a constant potential gradient (1.25 V cm(-1)) with processing fluids of tap water (TW), sodium dodecylsulfate (SDS) and citric acid (CA) for 5 days. Results showed that metal removal efficiency of heavy metals for EK-TW, EK-SDS and EK-CA systems are 11.2-60.0%, 37.2-76.5%, and 43.4-78.0%, respectively. A highest metal removal performance was found in EK-CA system. The removal priority of investigated metals from sludge by EK process was found as: Cu > Pb > Ni > Fe > Zn > Cr. The results of sequential extraction analysis revealed that the binding forms of heavy metals with sludge after electrokinetic process were highly depend upon the processing fluid operated. It was found that the binding forms of metals with sludge were changed from the more difficult extraction type (residual and sulfate fractions) to easier extraction types (exchangeable, sorbed, and organic fraction) after treatment by electrokinetic process. Results imply that if a proper treatment technology is followed by this EK process to remove metals more effectively, this treated sludge will be more beneficial for sludge utilization afterwards. Before it was reused, the risk associated with metals of more mobile forms to the environment need to be further investigated. The cost analysis was also evaluated for the investigated electrokinetic systems.     

Study on the migration mechanisms of water-soluble agents in high-pressure rotary jetting remediation

Environmental Science and Pollution Research - High-pressure rotary jetting (HPRJ) remediation is a recent-applied technology for in situ remediation of contaminated soils. The effectiveness of...     

N-doped carbon fibers in situ prepared by hydrothermal carbonization of Camellia sinensis branches waste for efficient removal of heavy metal ions

Environmental Science and Pollution Research - N-doped carbon fibers (NCFs) were in situ prepared by Camellia sinensis branches waste through hydrothermal carbonization with urea/ZnCl2 at...