Adsorption-Coagulation Mechanism of Composites in Treating Acid Mine Drainage

Abstract

In order to study the removal efficiency of Cu 2+ from acid mine drainage by prepared bentonite - steel slag composite particle s, adsorption experiment was carried out. The composite particles were characterized by X-ray Diffraction analysis technique (XRD), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared spectrometer (FTIR). The results show that: the composite particles can release alkali to neutralize the acid of acid mine drainage ; t he adsorption and chemical precipitation of Cu 2+ occur red in the whole reaction process ; t he removal amount of composite particles on Cu 2+ was 9.88 mg/g when the reaction reached equilibrium ; the FTIR spectra reveal ed the existence of surface complexation ; the SEM micrographs suggest ed that the composite particles would continue to adsorb and coagulate Cu 2+ after the composite particles surface adsorbing Cu 2+ and forming precipitate, namely, there was synergistic reaction of adsorption and coagulation ; the XRD patterns further showed the existence of cation exchange and revealed that the states of Cu 2+ in the surface of the composite particles was Cu -Si-O mineral phase and CuO(Cu(OH) 2 ) polymerization precipitation. The bentonite-steel slag composite particles which can play a role of adsorption-coagulation synergism are excellent multifunctional g reen environmental mineral materials to treat acid mine drainage containing heavy metal ions.