Effect of Fe loading quantity on reduction reactivity of nano zero-valent iron supported on chelating resin

Abstract

In this study, nanoscale zero-valent iron (NZVI) were immobilized within a chelating resin (DOW 3N). To investigate the effect of Fe loading on NZVI reactivity, three NZVI-resin composites with different Fe loading were obtained by preparing Fe(III) solution in 0, 30 and 70% (v/v) ethanol aqueous, respectively; the bromate was used as a model contaminant. TEM reveals that increasing the Fe loading resulted in much larger size and poor dispersion of nanoscale iron particles. The results indicated that the removal efficiency of bromate and the rate constant (K obs ) were decreased with increasing the Fe loading. For the NZVI-resin composite with lower Fe loading, the removal efficiency of bromate declined more significantly with the increase of DO concentrations. Under acidic conditions, decreasing the pH value had the most significant influence on NZVI-R3 with highest Fe loading for bromate removal; however, under alkaline conditions, the most significant influence of pH was on NZVI-R1 with lowest Fe loading. The effects of co-existing anions NO -3 , PO 3 -4 and HCO -3 were also investigated. All of the co-existing anions showed the inhibition to bromate reduction.

Pb(II) Removal from Aqueous Solutions by Adsorption on Stabilized Zero-Valent Iron Nanoparticles—A Green Approach

“…As a means of overcoming these disadvantages, the idea of immobilizing the ZVFe NPs into porous host materials was proposed and discussed in several research studies. Three main categories of porous host materials are available for the stabilization of iron NPs: (i) natural minerals, namely pillared clay [18], pumice granular [19,20], acid activated sepiolites [21,22], montmorillonite [23,24], kaolin [25], bentonite [26,27], zeolite [28][29][30], biochar [31,32], and charcoal [33]; (ii) biomaterials such as pine cone [34], aquatic plant Azolla filiculoides [35], cellulose nanofibrils [36], walnut shell [37], and macroporous alginate ( [38,39]); and (iii) synthetic materials such as cationic resin [40], anion exchange resin [41], porous carbon sheet [42], chelating resin [43], titanate nanotube [44], meso-porous silica carbon [45], layered double hydroxide [46,47], activated carbon [34,48,49], graphene oxide [45,50], chitosan [51], carbon nanotube [52], magnesium (hydr)oxide [19,53], and humic acid [54].…”