生物质灰对K+和NH4+吸附行为的分子模拟研究OA

To elucidate the adsorption mechanisms of ammonium(NH4+)and potassium(K+)ions by biomass ash,a combined approach of experimental characterization and molecular simulation was employed.X-ray diffraction(XRD)and X-ray fluorescence(XRF)analyses revealed that the primary mineral components of the biomass ash are ferric oxide(Fe2O3),silicon dioxide(SiO2),aluminum oxide(Al2O3),orthoclase(KAlSi3 O8),and albite(NaAlSi3 O8).Based on the Materials Studio software,molecular dynamics simulations were performed using the Forcite module,and quantum chemical calculations were carried out using the DMol3 module.Simulation results indicate that NH4+and K+ions preferentially adsorb near negatively charged oxygen atoms on the mineral surfaces,as revealed by electrostatic potential distributions and radial distribution function(RDF)analysis.Orthoclase and albite exhibit relatively weak adsorption capacity.Electron density distribution results indicate that K+adsorption is primarily physical,while NH4+may exhibit chemical adsorption.Interaction energy calculations indicate that the adsorption affinity of K+follows the order:Al2 O3>Fe2 O3>SiO2,whereas that of NH4+follows:Fe2 O3>Al2 O3>SiO2.