AUTHOR=Li Ning , Yuan Mingjie , Lu Sheng , Xiong Xiaoli , Xie Zhigang , Liu Yongsheng , Guan Wei 

TITLE=Highly effective removal of nickel ions from wastewater by calcium-iron layered double hydroxide

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.1089690

DOI=10.3389/fchem.2022.1089690

ISSN=2296-2646

ABSTRACT=<p>Water pollution due to heavy metals has become a universal environmental problem. Ni(II) is a common heavy metal ion in polluted wastewater, which has high toxicity and carcinogenicity. In this study, the structure of a calcium-iron layered double hydroxide (Ca-Fe-LDHs) was synthesized and characterized by FTIR, XRD, SEM and XPS. Then, Ni(II) ion was effectively removed by Ca-Fe-LDHs and its mechanism for this materials was described. The maximum adsorption capacity of Ni(II) for Ca-Fe-LDHs was 418.9 mg‧g<sup>−1</sup> when the initial concentration of Ni(II) was 1 g/L. The adsorption and removal of Ni(II) by Ca-Fe-LDHs was attributed to the action of hydroxyl groups on the hydrotalcite, generating surface capture. Ni(OH)<sub>2</sub>)0.75(H<sub>2</sub>O)0.16(NiCO<sub>3</sub>)0.09, Ni(OH)<sub>2</sub>, NiO, NiSO<sub>4</sub> and other precipitates were generated on its surface. And a small amount of Ni-Fe-LDHs was generated through isomorphic transition before hydrolysis. Therefore, surface capture and isomorphic transition enhanced the removal efficiency of Ni(II) with Ca-Fe-LDHs, making Ca-Fe-LDHs as a potential material for effective removal of Ni(II).</p>