Title : Statistical investigation of the effects of magnetite nanoparticle composition on arsenic adsorption
Arsenic toxicity is a growing concern worldwide due to its numerous adverse health effects. To reduce the concentrations of arsenic in water to the prescribed limits, various interventions have been developed. Adsorption onto magnetite nanoparticles is an effective remediation method because of the ability of iron to bind arsenic, and the high surface areas and magnetic properties of the particles. Since the removal of arsenic from water has been reported to proceed via the oxidation of the more toxic of As (III) to As (V), manganese, a natural oxidant commonly found in iron rich soils was introduced into the magnetite matrix to aid in As (III) removal. Response surface methodology was used to study the effects of the interactions of ferrous, ferric and manganese ions on As (III) concentration reduction in solution. A quadratic model with correlation coefficient of 0.9985 was used to model the data. The model indicated that Fe3+/Fe2+ and Fe3+/Mn2+ interactions were significant with the latter contributing positively to the reduction of As (III) concentration in solution. Response surface plots indicated that increasing manganese and ferric ions increased the reduction of As (III) concentration in solution. Increasing the Fe3+/Fe2+ ratio resulted in the formation of smaller nuclei resulting in higher adsorption. Diffraction peaks showed a single phase for Manganese doped magnetite confirming manganese substitution in the magnetite lattice without the formation of additional phases. Manganese substitution increased As (III) oxidation and adsorption. XPS results indicated that both As (III) and As (V) were present on the adsorbent surface confirming that the reduction of As (III) concentration in solution was a result of oxidation-coupled adsorption.
Audience takea away:
- The use of statistical tools in the design of experiments
- The application of experimental design in the optimization of synthetic materials to achieve desirable products
- The incorporation of materials to improve desired properties.
- This presentation will help researchers in the design of their experiments and the interpretation of data to extract valuable information from experimental findings.
- It also significantly reduces the number of experiments one has to conduct while providing all the information required to make research conclusions.