Effects of groundwater solutes on colloidal stability of polymer-coated and bare nanosized zero-valent iron particles

AbstractColloidal stabilities of polymer-coated nanosized zero-valent iron (pNZVI) and bare nanosized zero-valent iron (bNZVI) particles were investigated in the presence of groundwater solutes, such as Suwannee River natural organic matter (SRNOM), Pony Lake fulvic acid (PLFA), sodium ion, and calcium ion. Measurements of hydrodynamic diameter and zeta-potential showed that dissolved organic matters (SRNOM and PLFA) enhanced the stability of bNZVI particles, but that they did not affect the stability of pNZVI particles. These measurements also showed that the stability of pNZVI particles was inhibited by the cations but that the effect of the cations on bNZVI particles was inconclusive. The sedimentation test confirmed that the stability of pNZVI particles was inhibited by the sodium and calcium ions. The sedimentation test identified that the stability of bNZVI particles was inhibited only in the presence of calcium ion. The predictions on the stability of NZVI particles based on the Derjaguin–Landau–Ve...