Coupling adsorption and reduction for tellurium recovery by hierarchical porous nanoscale zero-valent iron (NZVI) /LDOs composites

Abstract

The efficient recovery of tellurium from aqueous solution is essential from the viewpoint of non-ferrous metal resource exploitation and environmental protection. In this work, Mg–Al LDOs (layered double oxides) was synthesized by a facile biotemplate method, and then loaded with NZVI to realize coupling adsorption and reduction for tellurium recovery. Through the SEM, TEM, XRD, and BET tests, the morphology and crystal structure of this NZVI/LDOs composites were determined, and it was found that NZVI can be distributed on the surface of the LDOs sheet uniformly with large specific surface area of 134.04 m2/g and pore size of 10.15 nm. The prepared NZVI/LDOs composites exhibited excellent tellurium adsorption capacity (the removal rate can reach more than 99%) and pH, adsorption concentration and temperature are controlled to find the optimal adsorption conditions. The XPS analysis confirmed that the reduced tellurium adhered to the LDOs surface in elemental form, demonstrating the feasibility of the method. The combination of NZVI and Mg–Al LDOs solved the defects of bare NZVI and greatly improved the adsorption performance which has a good application prospect in the future recovery of tellurium.

Keywords

• Nanoscale zero-valent iron
• Tellurium
• Layered double hydroxide
• Coupling adsorption
• Reduction