Critical layer in liquid-solid system influencing the remediation of chromium using zeolite-supported sulfide nano zero-valent iron

摘要

Sulfidated nano zero-valent iron particles were immobilized on ZSM-5 zeolite(Z/S-nZⅥ)and used for hexavalent chromium(Cr(Ⅵ))remediation.The performance of Z/S-nZⅥimproved with the increase in Cr(Ⅵ)concentration(0.6).Moreover,the removal mechanisms of Cr(Ⅵ)were elucidated through XRD,transmission electron microscopy(TEM)and XPS techniques.This results demonstrate that the species of chromium in the critical layer changed from Cr(Ⅲ)to Cr(Ⅵ)as the concentration of chromium increased from low to high.Furthermore,the critical layer was composed of Cr(Ⅵ),Fe(Ⅱ),O and H elements.Additionally,the experiments of coexisting ions and aging time confirmed that Z/S-nZⅥpossessed high selectivity and stability to ensure efficiency and cost-effectiveness in practical applications.