Super‐Stable Mineralization of Ni²⁺ Ions from Wastewater using CaFe Layered Double Hydroxide

Abstract

The dealing/recycling of Ni‐containing wastewater pollution has aroused great attention both from environmental science and resource utilization perspectives. Herein, a classic CaFe‐layered double hydroxide (CaFe‐LDH) stabilizer, which exhibits a super‐stable mineralization efficiency for removing Ni2+ ions with a maximum saturated removal capacity of 321 mg g−1 is prepared. This stabilizer can remove not only 10 000 mg L−1 Ni2+ ions to a few mg L−1, but also 1 mg L−1 Ni2+ ions to 2 µg L−1. Moreover, the CaFe‐LDH shows great mineralization capability for the real Ni‐containing electroplating solution. It is demonstrated by ex situ X‐ray diffraction and extended X‐ray absorption fine structure characterization that the isomorphous substitution of Ca2+ by Ni2+ in the laminate of LDH dominates the mineralization process, and the CaFe‐LDH is transformed to the corresponding NiCaFe‐LDH accordingly. Further application of the resultant NiCaFe‐LDH shows improved electrocatalytic oxygen evolution reaction and photocatalytic CO2 reduction activities. This work paves great way for Ni2+ ion removal from wastewater and utilization of the recycled Ni resource.

A Quasi-Metal–Organic Framework Based on Cobalt for Improved Catalytic Conversion of Aquatic Pollutant 4-Nitrophenol

“…Mechanism studies indicate that the reduction of 4-NP follows the LH model, and the attack of 4-NP by the surface-attached hydrogen species is the rate-determining step. Thus, the present study shows that going beyond generation of defects, a deeper partial destruction of the MOF structure appears as a general, economic, and green method to obtain advanced catalysts with application in the removal of organic pollutants from contaminated waste water and even inorganic cations by incorporation into the QT-x framework …”

Scalable fabrication of LDH-based adsorbent for the removal of nitrate with enhanced performance

“…16 It is obvious that Mg 3 Al-LDHs (NaOH) showed a stronger peak intensity and narrower peak width than that of the Mg 3 Al-LDHs (Na 2 CO 3 and NaOH + Na 2 CO 3 ), especially for the peaks of (003), (006) and (012), suggesting that Mg 3 Al-LDHs (NaOH) had better crystallinity. 17 The lattice parameters were calculated to further study the structures of the LDHs, which are summarized in Table S4 (ESI†), where D a and D c represent the crystal grain size of the Mg 3 Al-LDHs on the a -axis and c -axis, respectively. According to previous reports, the value of D a / D c reflects the shape of the crystal grains.…”

“…16 It is obvious that Mg 3 Al-LDHs (NaOH) showed a stronger peak intensity and narrower peak width than that of the Mg 3 Al-LDHs (Na 2 CO 3 and NaOH + Na 2 CO 3 ), especially for the peaks of (003), ( 006) and (012), suggesting that Mg 3 Al-LDHs (NaOH) had better crystallinity. 17 The lattice parameters were calculated to further study the structures of the LDHs, which are summarized in Table S4 obviously different, suggesting that the alkali source has a great influence on their layer composition. In the case of Mg 3 Al-LDHs (Na 2 CO 3 and NaOH + Na 2 CO 3 ), the larger d (003) -spacing is attributed to the compositing speed due to the electrical neutrality.…”

Layered double hydroxide-based nanomaterials for biomedical applications

“…Bulk LDHs are generally synthesized by well-established methods, including co-precipitation, hydrothermal synthesis, separate nucleation and aging steps, and anion exchange. 71,72 (a) Co-precipitation. Co-precipitation has been the most commonly used method to directly synthesize bulk LDHs in an one-step process with high yields since it was first used to synthesize MgAl-LDHs in 1942.…”

“…Bulk LDHs are generally synthesized by well-established methods, including co-precipitation, hydrothermal synthesis, separate nucleation and aging steps, and anion exchange. 71,72…”