Effects of EDTA on the accelerated carbonation behavior of steel slag used as cementitious materials

Mechanistic insights into the co-recovery of nickel and iron via integrated carbon mineralization of serpentinized peridotite by harnessing organic ligands

“…28,30,71 The introduction of Na 2 H 2 EDTA·2H 2 O into the system facilitate the presence of HEDTA 3− ions, which have been reported to be the dominant EDTA species at pH 7–10 and the pH range at which the carbon mineralization process is occurring (R6). 8,73–76 The formation of HEDTA 3− ions facilitates a catalytic effect on carbon mineralization due to their chelation effect (R7). 73,74 Thus, NaHCO 3 and Na 2 H 2 EDTA·2H 2 O creates a buffered system, contributing to the regulation of pH for mineral dissolution, metal chelation, and magnesium carbonate precipitation as shown in reactions, R5–R8 below.NaHCO 3 − + OH − + CO 2 → 2CO 3 2− + 2H + + Na + Na 2 H 2 EDTA·2H 2 O → HEDTA 3− + H + + 2Na + + 2H 2 O(Mg,Fe)SiO 4(s) + 4H aq + + HEDTA 3− → Mg aq 2+ + [Fe(HEDTA)] (aq) − + SiO 2(aq) + 2H 2 OMg aq 2+ + CO 3 2− → MgCO 3 …”

“…8,73–76 The formation of HEDTA 3− ions facilitates a catalytic effect on carbon mineralization due to their chelation effect (R7). 73,74 Thus, NaHCO 3 and Na 2 H 2 EDTA·2H 2 O creates a buffered system, contributing to the regulation of pH for mineral dissolution, metal chelation, and magnesium carbonate precipitation as shown in reactions, R5–R8 below.NaHCO 3 − + OH − + CO 2 → 2CO 3 2− + 2H + + Na + Na 2 H 2 EDTA·2H 2 O → HEDTA 3− + H + + 2Na + + 2H 2 O(Mg,Fe)SiO 4(s) + 4H aq + + HEDTA 3− → Mg aq 2+ + [Fe(HEDTA)] (aq) − + SiO 2(aq) + 2H 2 OMg aq 2+ + CO 3 2− → MgCO 3 …”

“…The influence of chemical additives, including bicarbonate compounds like NaHCO 3 , and organic ligands such as Na 2 H 2 EDTAÁ2H 2 O, have been investigated for their individual effects on carbon mineralization efficiency in direct carbon mineralization studies. 2,8,22,28,30,31,48,[70][71][72][73][74] It has been reported that the addition of 2 M NaHCO 3 significantly enhances the carbon mineralization efficiency by approximately 50-60%. 8,28 Upon dissolution in the aqueous phase, NaHCO 3 dissociates to produce bicarbonate ions (R2).…”

“…8,[73][74][75][76] The formation of HEDTA 3À ions facilitates a catalytic effect on carbon mineralization due to their chelation effect (R7). 73,74 Thus, NaHCO 3 and Na 2 H 2 EDTAÁ2H 2 O creates a buffered system, contributing to the regulation of pH for mineral dissolution, metal chelation, and magnesium carbonate precipitation as shown in reactions, R5-R8 below. hydration.…”

Accelerated Carbonation of Steel Slag and Their Valorisation in Cement Products: A Review

“…These agents are molecules capable of establishing multiple bonds with a single metal ion, effectively capturing the ion, and maintaining it in solution (Chen et al, 2023).…”