title: An integrated experimental-modeling approach to study the acid leaching behavior of lead from sub-micrometer lead silicate glass particles.
abstract: This work focuses on the development of a procedure to study the mechanism of leaching of lead from sub-micrometer lead glass particles using 0.3 mo ll(-1) HNO3 as a leachant. Glass particles with an effective size distribution range from 0.05 to 1.4 μm were generated by laser ablation (213 nm Nd:YAG laser) and collected on an inline 0.2 μm syringe filter. Subsequently, the glass particles on the filter were subjected to online leaching and continuous monitoring of lead (Pb-208) in the leachate by quadrupole ICP-MS. The lead leaching profile, aided by the particle size distribution information from cascade impaction, was numerically fitted to a mathematical model based on the glass intraparticle diffusion, liquid film distribution and thermodynamic glass-leachant distribution equilibrium. The findings of the modeling show that the rate-limiting step of leaching is the migration of lead from the core to the surface of the glass particle by an ion-exchange mechanism, governed by the apparent intraparticle lead diffusivity in glass which was calculated to be 3.1 × 10(-18) m(2)s(-1). Lead leaching is illustrated in the form of graphs and animations of intraparticle lead release (in time and intraparticle position) from particles with sizes of 0.1 and 0.3 μm.
authors.affiliation: Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia. Electronic address: elteren@ki.si.
authors.forename: Johannes T
authors.initials: JT
authors.lastname: van Elteren
authors.forename: Miha
authors.initials: M
authors.lastname: Grilc
authors.forename: Michael P
authors.initials: MP
authors.lastname: Beeston
authors.forename: Milagros Santacatalina
authors.initials: MS
authors.lastname: Reig
authors.forename: Irena
authors.initials: I
authors.lastname: Grgić
mesh_terms: D000143:Acids / Q000737:chemistry*; D005898:Glass; D007854:Lead / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008962:Models, Theoretical; D010316:Particle Size; D017640:Silicates / Q000737:chemistry*
chemical_list: D000143:Acids; D017640:Silicates; C044795:lead silicate; D007854:Lead
keywords: Ion-exchange; Kinetics; Mechanism; Nanoparticles; Network hydrolysis