( cest2017_00760) Kinetics of chromate reduction by nano zero valent iron incorporated in a porous matrix

摘要

Incorporation of nanozero valent iron (nZVI) in a porousmatrix is an innovative technology for the treatment ofcontaminated waters. Aim of the technology is to exploitthe high reactivity of nZVI towards a wide spectrum ofcontaminants, avoiding important handling problemswhich arise when bare nZVI suspensions are used. In thisstudy nZVI was incorporated in the matrix of a cationexchangeresin (Amberlyst 15), by applying a greensynthesis procedure, and the composite material was usedfor the removal of Cr(VI) from aqueous solutions.Reduction kinetics was studied by conducting batch tests.The main investigated parameters were the particle size ofnZVI loaded resin beads (R-nFe), the concentration ofCr(VI) and the amount of R-nFe per volume of solution.A model was developed to describe the reduction kinetics,taking into consideration two interrelated processes: (a) thediffusion of contaminant inside the network of pores and(b) the chemical reaction between the contaminant and ironnanoparticles which are homogenously dispersed inside theporous beads. The effective diffusion coefficient, De, andthe kinetic constant, k, were initially determined by fittingthe model equations to an initial set of experimental data,and then were successfully used to predict the kineticsunder different experimental conditions.