Insights into environmental remediation of heavy metal and organic pollutants: Simultaneous removal of hexavalent chromium and dye from wastewater by zero-valent iron with ligand-enhanced reactivity

Synthesis of novel CO 3 2− /Cl − -bearing 3(Mg + Zn)/(Al + Fe) layered double hydroxides for the removal of anionic hazards

“…Many of these complex compounds are also 18 toxic in nature and can cause direct destruction or affect capabilities 19 of various living organisms [6]. 20 Many physical processes have been applied for treatment of 21 hazardous anionic effluents such as coagulation, flocculation, 22 bioremediation, photo-decomposition and ultra-filtration, chemi- 23 cal oxidation and membrane separation [1,[3][4][5]7]. However, these 24 techniques have several disadvantages.…”

“…However, these 24 techniques have several disadvantages. For example, the 25 bioremediation [3,4], photo-decomposition [5] and reduction- 26 co-precipitation [7] processes are slow, need external additives 27 and may be inadequate to remove the threat of the degraded 28 components as the case with heavy metal-dyes. Hence, adsorption 29 is preferred over these processes and widely applied because it can 30 be used for removing anionic hazards under 'soft' conditions, 31 without the generation of secondary hazardous materials.…”

EDDS-assisted reduction of Cr(VI) by nanoscale zero-valent iron

“…To avoid the formation of passivation layer on the external surface of nZVI, one of the approaches is to apply Fe-chelant such as ethylene diamine tetraacetic acid (EDTA) and oxalate, which have been widely investigated to chelate Fe(II) and Fe(III) [18][19][20]. Zhang et al [21] demonstrated that the addition of EDTA significantly enhanced the rates and the extent of carbon tetrachloride (CT) removal by microscale ZVI, which was attributed to the elimination of a surface passivation layer of Fe(III) (hydro)oxides on the microscale ZVI through chelating of EDTA with Fe(III), which maintained the exposure of active sites on the ZVI surface to CT. Fu et al [20] also demonstrated that the oxalate ligands can significantly increase the removal efficiency of Cr(VI) and dye since the ligands can accelerate ferrous iron oxidation and increase the generation of hydroxyl radical.…”

Effective removal of nemacide fosthiazate from an aqueous solution using zero-valent iron

“…In particular, ZVI is an inexpensive and moderately strong reducing agent which has been applied in the laboratory to treat various environmental pollutants, such as heavy metals (Fu et al, 2013), azo dyes (Cao et al, 1999;Nam et al, 2000;Perey et al, 2002), explosives (Koutsospyros et al, 2012;Wanaratna et al, 2006;Oh et al, 2005aOh et al, , 2005b, halogenated organic compounds (Johnson et al, 1996;Gillham and Ohannesin, 1994), highly toxic chemicals (Oh et al, 2006;Lee et al, 2009), nitroaromatics compounds (Shen et al, 2013;Devlin et al, 1998;Agrawal and Tratnyek, 1995), and nitrate (Huang et al, 1998). ZVI is commonly used as a treatment technique for toxic and refractory waste water, such as bromoamine acid waste water, coking waste water, olive mill waste water, industrial waste water, and ABS resin waste water (Fan et al, 2009;Kallel et al, 2009;Ma and Zhang, 2008;Lai et al, 2009Lai et al, , 2012.…”