Effect of kaolinite, silica fines and pH on transport of polymer-modified zero valent iron nano-particles in heterogeneous porous media

► At pH < 7 anionic polyelectrolyte coated NZVI aggregates and deposition increases. ► Surface charge heterogeneity on sand and clay particles increased deposition of NZVI. ► Pre-adsorbing polyelectrolyte on sand and clay and decreases deposition.