Study The Mechanism Of Acid Mine Drainage Containing Heavy Metal Ions By Bentonite-steel Slag Composite Particle

In order to study purifying effect and the mechanism on acid mine drainage containing heavy metal ions by bentonite-steel slag composite particle,this paper combined the macro and micro experiments to explore the treatment of Fe²⁺?Mn²⁺?Cu²⁺?Zn²⁺by composite particle.Adsorption,ion-exchange action,complexation reaction,precipitation,coagulation mechanism and laws of heavy metal ions had explored preliminary.Through measure the emitting quantity of Na⁺?Ca²⁺from composite particle in the treatment of wastewater,the results show that ion-exchange action happened the reaction in the first 5-10min.Ion-exchange action had been proved by XRD.And after the reaction can be determined that through XRD composite particle layer spacing significantly bigger,and the layer spacing were consistent with the effective hydrated ionic radius.Through measure the relationship of removal amount of heavy metal ions in different ionic strength,the surface complexation were found in the first 300min.According to XRD measurement,treated composite particles had a new combined with Si-O mineral phases.The changement of functional groups of treated composite particles by FT-IR,and the XRD proved the existence of the surface complexation.Through measured the total removal efficiency and experiment phenomenon of composite particle,dealkalization particles and kalizing on the treatment of heavy metal ions to reveal that chemical precipitation almost occurred in the whole process;At the same time,comparing three removal amount,experimental phenomenon and the morphology characteristics of treated composite particles in the different phases by SEM could reveal that the absorbed composite particles continued to adsorb heavy metal ions or precipitate.There were adsorption-coagulation synergetic effect.The adsorption kinetics of heavy metal ions were in coincidence with pseudo-second-order kinetic model.At the beginning of the reaction,adsorption rate was controlled by liquid film diffusion;after 30min,it was controlled by intra-particle diffusion.The adsorption of composite particle on heavy metal ions in the multicomponent system confirmed the removal law between various heavy metal ions.And the adsorption order followed the law of preferential adsorption was revealed.The adsorption order of four heavy metals by composite particle was Fe²⁺>Cu²⁺>Zn²⁺>Mn²⁺.In line with the previous empirical studies.Further revealing the mechanism and laws of adsorption,precipitation,coagulation.