Precipitation (chemical)

Soil contamination by potentially toxic elements (PTEs) has led to adverse environmental impacts. In this review, we discussed remediation of PTEs contaminated soils through immobilization techniques using different soil amendments with respect to type of element, soil, and amendment, immobilization efficiency, underlying mechanisms, and field applicability. Soil amendments such as manure, compost, biochar, clay minerals, phosphate compounds, coal fly ash, and liming materials are widely used as immobilizing agents for PTEs.
The two-dimensional (2D) ultrathin Mg-Al layered double hydroxide modified by magnetic Fe3O4 (Fe3O4/Mg-Al LDH) was successfully synthesized via the co-precipitation method. The Fe3O4/Mg-Al LDH not only exhibits superior separation efficiency of charge carriers but also possesses signally enhanced photocatalytic activity for CO2 reduction than Mg-Al LDH. The as-prepared Fe3O4/Mg-Al LDH affords the CO and CH4 generation rate of 442.2 µmol g−1 h−1 and 223.9 µmol g−1 h−1. The enhanced reduction CO2 activity mainly comes from synergetic effect of Fe3O4 and ultrathin Mg-Al LDH.