On the nonlinear relationship between k(obs) and reductant mass loading in iron batch systems.

摘要: A first-order relationship between reaction rate and reductant loading is commonly invoked (but rarely verified) for granular iron batch systems. In this study, a linear the pseudo-first-order constant (kobs) polyhalogenated alkane reduction mass (ρm) was only obtained when appeared to be mass-transport-limited. For most alkyl polyhalides, nonlinear observed under various experimental conditions, causing surface-area-normalized constants (kSA) decrease by as much an order of magnitude with increasing ρm. While detailed explanation nonlinearity remains unclear, in ρm (from plots log(kobs) versus log(ρm)) approached unity system pH decreased, suggesting that behavior may linked changes thickness passive oxide overlayer. We strong correlations kobs values concentration aqueous iron(II) generated over 24 h period syst...