Effects of electrokinetic treatment of contaminated sludge on migration and transformation of Cd, Ni and Zn in various bonding states

The Application of Solar Cells in the Electrokinetic Remediation of Metal Contaminated Sediments

“…The size of the oxidizable fraction in the anode region decreased, indicating the oxidation of sulphides and the degradation of organic compounds. In the cathode region, the oxidizable and residual fractions significantly increased, indicating the accumulation of Ni in the cathode area, mostly in relatively immobile complexes, such as fixed on the sludge hydroxides due to the high pH, as suggested in the literature (Rajic et al, 2011;Gao et al, 2013).…”

“…A large number of researchers have confirmed the presence of Cd in this fraction (Fuller and Davis, 1987;Gonzalez et al, 1994;Mermut et al, 1996;Davies, 2000, 2003;Jain, 2004;Mingbiao et al, 2008;Korfali and Jurdi, 2011). In the anode region, over the course of the treatment, the percentage of total Cd present in the first fraction decreased, indicating that the majority of the exchangeable Cd migrated towards the cathode region, as in Gao et al (2013). In the cathode region, the Cd is immobilised in hydroxyl complexes and precipitates due to the high pH (Giannis et al, 2010), which explains the increase in oxidizable and residual fractions in this region.…”

“…Speciation of Cd, Zn and Ni in the EK Cell. During the application of an electric field, changes in the sediment environment lead to different transformations (Gao et al, 2013). These changes may be caused by reductions in the moisture and organic contents of the sediment, decreases in the conductivity, etc.…”

Removal of heavy metals with sequential sludge washing techniques using saponin: optimization conditions, kinetics, removal effectiveness, binding intensity, mobility and mechanism

“…These methods include chemical treatments, ion exchange methods, thermal treatments, bioleaching methods, electrokinetics methods, ultrasound-assisted nitric acid methods. 4,[6][7][8][9][10][11][12][13][14][15][16] Especially, the chemical methods have been focused more than others methods by researcher, due to its simple operation processes, the short operation times, and high removal efficiency for heavy metals in the sludge. 8 Previous studies have indicated that heavy metals extraction efficiency mainly depends on chemical reagent type, contact time, high temperature, low pH, and long contact time could enhance heavy metal extraction.…”

Application of sodium titanate nanofibers as constructed wetland fillers for efficient removal of heavy metal ions from wastewater

“…The problem of water pollution by heavy metal ions is of great concern. Heavy metal ions in water are bioavailable and accumulate through food chains (Suanon et al, 2016;Gao et al, 2013), posing a threat to the aquatic ecosystem and human health.…”