The environmental fate, and ultimately bioavailability, of arsenic compounds depends on their surface interactions with reactive components in soil. These components include minerals and natural organic matter (NOM). In general, molecular-level understanding of surface processes at solid/liquid interfaces demands using simple model systems and integrating spectroscopic, calorimetric, computational chemistry and mathematical modeling tools. In this talk, I will show results on the surface chemistry of arsenate, methylated and aromatic arsenicals, with hematite nanoparticles. Spectroscopic data were collected using attenuated total internal reflection Fourier transform infrared spectroscopy (ATR-FTIR) and experimental results were complemented with DFT calculations. Flow calorimetric measurements were also completed to gain insight into surface charge and heats of adsorption. Thermodynamic binding constants were extracted from applying the triple layer surface complexation model to adsorption isotherm and pH-envelope data. The kinetics of arsenicals interaction with hematite nanoparticles pre-exposed to three types of low molecular weight organics will also be discussed. The significance of these results will be discussed in relation to improving modeling tools for accurate quantification of environmental exposure to arsenic.

Relevant papers:

Eid, Kraemer, Al-Abadleh. Surface Chemistry of Bovine Serum Albumin with Hematite Nanoparticles and its Effect on Arsenate Adsorption. Environmental Chemistry, 2021, 18(4), 177-189.

Situm, A.; Rahman, M. A.; Allen, N.; Kabengi, N. J.; Al-Abadleh, H. A., ATR-FTIR and flow microcalorimetry studies on the initial binding kinetics of arsenicals at the organic-hematite interface. J. Phys. Chem. A 2017, 121 5569-5579.

Situm, A.; Rahman, M. A.; Goldberg, S.; Al-Abadleh, H. A., Spectral characterization and surface complexation modeling of organics on hematite nanoparticles: Role of electrolytes in the binding mechanism. Environ. Sci. Nano 2016, 3 910-926.

Sabur, M. A.; Goldberg, S.; Gale, A.; Kabengi, N. J.; Al-Abadleh, H. A., Temperature-dependent ATR-FTIR and calorimetric studies on arsenicals adsorption from solution to hematite nanoparticles. Langmuir 2015, 31 (9), 2749-2760.

Hind Al-Abadleh

Appearances