Innovative recovery of matrix layered double hydroxide from simulated acid mine wastewater for the removal of copper and cadmium from wastewater

Abstract

This study innovatively added biochar to optimize regulation in the neutralization process of simulated acid mine drainage (AMD) and recovered a new type of matrix layered double hydroxides (MLDH), which can be used to remove copper (Cu(II)) and cadmium (Cd(II)) from wastewater. A series of batch experiments show that MLDH with strong selective removal ability of Cu(II) and Cd(II) can be successfully obtained by adding biochar (BC) at pH = 5 end in the neutralization process. Kinetic and isotherm modeling studies indicated that the removal of Cu(II) and Cd(II) by the MLDH was a chemical multilayer adsorption process. The removal mechanism of Cu(II) and Cd(II) was further analyzed through related characterization analysis with contribution rate calculation: the removal rates of Cu(II) and Cd(II) by ion exchange were 42.7% and 26%, while that by precipitation were 34.5% and 49.9%, respectively. This study can provide a theoretical reference and experimental basis for the recovery and utilization of valuable by-products in AMD and the treatment of heavy metal wastewater.

Keywords: Heavy metal; Matrix layered double hydroxides; Resourceful utilization of AMD; Wastewater.