Experimental and simulation results of the adsorption of Mo and V onto ferrihydrite

Loredana Brinza,Hong Phuc Vu,Mariana Neamtu,Liane G Benning

doi:10.1038/s41598-018-37875-y

Abstract

This study aims to highlight discrepancies between experimental and simulation linked to the mechanisms of Mo and V adsorption onto ferrihydrite (FHY) nanoparticles. We have measured adsorption capacities and uptake efficiencies and then fitted and compared these with outputs from various geochemical and adsorption models that were run as a function of pH, surface area (SA) and ferrihydrite particles size distributions. Our results revealed that the experimental data for the Mo system could be fitted very well, but this was not the case for the V system, when a model default value for the SA of FHY of 600 m2 g−1 was used. The discrepancy in the results for the V system can be explained by the lack of specific V species and/or associated constants in databases and variation in software versions, which change the outputted chemical species. Our comparative results also confirm that any experimental variables used as modelling inputs need to be checked carefully prior to any modelling exercises.

Highlights

ObjectivesThis study aims to highlight discrepancies between experimental and simulation linked to the mechanisms of Mo and V adsorption onto ferrihydrite (FHY) nanoparticles
We showed that combining experimentally derived FHY characteristics for surface area (~200 m2 g−1), surface charge (PZC 7.89), particle/aggregate size (4 nm to 75 μm) with quantitative and pH dependent adsorption data resulted in V having a higher affinity for FHY surface sites compared to Mo, a difference explained by the V and Mo anion sizes and valences
The sorption experiments revealed a change in the sorption mechanism as a function of the pH and anion valence

Summary

Objectives

This study aims to highlight discrepancies between experimental and simulation linked to the mechanisms of Mo and V adsorption onto ferrihydrite (FHY) nanoparticles. With this study we aimed only to compare our new experimental data on Mo and V adsorption with existing databases and model outputs and not to change modelling codes or databases

Methods

Results

Conclusion