A one-step electrochlorination/electroflotation process for the treatment of heavy metals wastewater in presence of EDTA

Cyanide oxidation by singlet oxygen generated via reaction between H 2 O 2 from cathodic reduction and OCl − from anodic oxidation

“…In A system, Cl 2 was in situ generated by losing two electron oxidation of Cl À on the anode and it was then converted to hypochlorous acid and hypochlorite via the following reactions (1)-(3) [29]:…”

Photo-assisted electrolytic decomplexation of Cu-EDTA and Cu recovery enhanced by H 2 O 2 and electro-generated active chlorine

“…In the case of EDTA, it was reported that in situ generated active chlorine allowed the decomplexation of metal-EDTA, which was beneficial to the metal recovery [18]. Furthermore, the combination of UV and chlorination was proved to be an improved oxidation technology in the aspect of some organics like metoprolol compared with pure chlorination due to the photogenerated hydroxyl radicals and chlorine radicals [19].…”

Recovery of Cu(II) by chemical reduction using sodium dithionite

“…Other than heavy metals, these wastewaters come with various organic or inorganic chelating agents such as EDTA (ethylenediaminetetraacetic acid), NTA (nitrilotriacetic acid), cyanide, and ammonia, which make removal of heavy metals from these wastewaters much more challenging (Jiang et al, 2008(Jiang et al, , 2010Khelifa et al, 2013). It has been shown that metal removal efficiency by adsorption, coagulation or electrocoagulation is greatly impaired by presence of EDTA (Izquierdo et al, 2013;Khelifa et al, 2013). Destruction of metal/chelate complexes is the key to obtain efficient metal removal (Jiang et al, 2008).…”