Hardness and carbonate effects on the reactivity of zero-valent iron for Cr(VI) removal

Reduction of Hexavalent Chromium Using Sorbaria sorbifolia Aqueous Leaf Extract

“…The obtained results presented in Figure 5 reveal that Cr(VI) reduction efficiency decreased sharply with increasing hardness of the solution; 92% reduction efficiency is obtainable at 2 mM hardness level which decreases to 68% at 5 mM. Similar observations have been recorded in the literature which indicate that presence of Ca 2+ hardness with carbonate has resulted in a substantial drop in Cr(VI) reduction efficiency [29,30]. It is important to emphasize that the divalent cation (Ca 2+ ) has a more significant effect on Cr(VI) reduction efficiency than monovalent cations (Na + ).…”

Influence of dissolved inorganic carbon and calcium on gas formation and accumulation in iron permeable reactive barriers

“…Their formation therefore enhances further formation and reduction of hydrogen ions. Lo et al (2006) and Wu et al (2009) reported that mainly calcium carbonate causes a decrease in ZVI reactivity, while other reports attributed the main passivating effect to chukanovite (Kohn et al, 2005) or chukanovite with aragonite depositions (Jeen et al, 2007). Other investigations revealed siderite (FeCO 3 ) to be the main precipitate (Agrawal et al, 2002;Mackenzie et al, 1999).…”

Chromate reduction by waste iron from electroplating wastewater using plug flow reactor

“…There are many researches in which ZVI particle is used to treat chromate for groundwater and wastewater in medium pH through batch modes [2,[5][6][7][8][9][10][11][12][13][14]. These researches all concluded that chromate reduction efficiencies could be enhanced through increase in acidity.…”