Selective removal of As(V) from wastewater with high efficiency by glycine-modified Fe/Zn-layered double hydroxides

Layered double hydroxides (LDHs) have attracted significant attention in the removal of oxyanions due to their large surface area and excellent thermal stability. However, the electrostatic repulsion of the same charges causes a poor adsorption effect of LDH for oxyanions. Additionally, the selectivity of LDH for specific oxyanion remains poor. To improve its adsorption effect and selectivity, glycine-modified Fe/Zn-LDH (GFeZn) was prepared. The GFe(1)Zn(1), with a Fe/Zn mole ratio of 1:1, achieved excellent selectivity for As(V). Langmuir isotherms model and pseudo-second-order kinetics model were followed in the adsorption of GFe(1)Zn(1) for As(V). The saturated adsorption capacity for As(V) reaches 859.52 mg.g(-1), while the adsorption equilibrium was established between 60 and 120 min. GFe(1)Zn(1) has excellent reusability on the adsorption of As(V). The adsorption capacity decreased by about 13.30% in 5 adsorption/desorption cycles. This study offers a new method to remove As(V) from polluted water selectively.

Automated summary

The study focuses on improving the adsorption effect and selectivity of layered double hydroxides (LDHs) for oxyanions by preparing glycine-modified Fe/Zn-LDH (GFeZn). The GFe(1)Zn(1) with a Fe/Zn mole ratio of 1:1 achieved excellent selectivity for As(V), with a saturated adsorption capacity of 859.52 mg/g and an adsorption equilibrium established between 60 and 120 minutes. The GFe(1)Zn(1) also showed excellent reusability with only a 13.30% decrease in adsorption capacity after 5 adsorption/desorption cycles, providing a new method for selectively removing As(V) from polluted water.