Efficiency of Pb(II) and Mo(VI) Removal by Kaolinite Impregnated with Zero-Valent Iron Particles

Abstract

Abstract. In this work, kaolinite modified with zero-valent iron was synthesized and used as a sorbent for Pb(II) and Mo(VI) removal from aqueous solutions. The obtained material was characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The methods revealed successful modification by the Fe 0 particles precipitation on the surface of well-ordered kaolinite. The sorption experiment results showed a significant increase of sorption capacity in relation to the raw kaolinite. The kaolinite with 25% content of Fe 0 was found to be the best material for Pb(II) and Mo(VI) removal, resulting in approximately 500 mmol·kg -1 and 350 mmol·kg -1 sorption, respectively. The possible mechanisms responsible for metals' removal were identified as reduction by Fe 0 'core' and adsorption on the iron hydroxides 'shell'. The study indicated that the obtained material is capable of efficient Pb(II) and Mo(VI) removal and may be an interesting alternative to other methods used for heavy metals' removal.

Synthesis of zerovalent iron from water treatment residue as a conjugate with kaolin and its application for vanadium removal

“…An increase in the intensity of the basal spacing could be observed in both 10% and 25% KZVIs at 2.03 Å. However, the increment was noticed to be more prominent in 25% KZVI than in 10%, and these trends were quite similar to those earlier reported by Üzüm et al [22] and Rybka et al [20]. Rybka et al [20] also reported the presence of zerovalent iron at basal spacing of 2.92 Å and 2.03 Å, which was observed to be featureless in the 10% modified adsorbents but quite prominent in the 25% adsorbents.…”

“…However, the increment was noticed to be more prominent in 25% KZVI than in 10%, and these trends were quite similar to those earlier reported by Üzüm et al [22] and Rybka et al [20]. Rybka et al [20] also reported the presence of zerovalent iron at basal spacing of 2.92 Å and 2.03 Å, which was observed to be featureless in the 10% modified adsorbents but quite prominent in the 25% adsorbents. The lack of shift of the 7.2 Å basal spacing of the modified adsorbents indicated that ZVI particles were synthesized exclusively on the kaolin and intercalation did not occur.…”

“…According to the adsorption results presented in Fig. 1, kaolin clay was found to have exhibited the poorest removal rate; this is caused mainly by its lack of anion exchange capacity [20,21]. The amount of V adsorbed by iron sludge was quite significant when compared to kaolin, as the result revealed that more than 65% of the studied vanadium content (20 mg/l) had been removed.…”

“…The preparation of Syn-KZVI was achieved through the Fe (III) reduction method as described by Rybka et al [20]. Table 1 shows the exact mix proportion of the chemicals, reagents and materials used during the synthesis.…”