Title: Yang W., Guo L., Chuang C.-Y., Santschi P.H., Ayranov M., Schumann D. Influence of organic matter on the adsorption of ²¹⁰Pb, ²¹⁰Po and ⁷Be and their fractionation on nanoparticles in seawater. Earth and Planetary Science Letters, 2015, 423, 193-201.

Abstract:

Improved applications of ²¹⁰Po, ²¹⁰Pb and ⁷Be as geochemical proxies require more detailed understanding of their interactions with particles. Here, laboratory sorption experiments were carried out to examine the adsorption of ²¹⁰Po, ²¹⁰Pb and ⁷Be and their fractionation on inorganic nanoparticles, including SiO₂, CaCO₃, Al₂O₃, TiO₂ and Fe₂O₃, in the presence or absence of macromolecular organic compounds (MOCs) that include humic acids (HA), acid polysaccharides (APS) and proteins (BSA), in natural seawater. Results showed that nanoparticle sorption was not greatly enhanced over that of microparticles as would be expected from their much higher specific surface areas, likely indicating their aggregation in seawater. It was found that synergistic interactions between inorganic nanoparticles, MOCs, and radionuclides determined the sorption, although their adsorption was particle composition-dependent. MOCs enhanced the sorption of selected nuclides on most nanoparticles. On average, in the presence of MOCs, partition coefficients (K_c) of ²¹⁰Po, ²¹⁰Pb, and ⁷Be on nanoparticles increased 2.9-, 5.0- and 5.9-fold, respectively. The effect of MOCs could be explained for ²¹⁰Po and ²¹⁰Pb from their different log K_c values on inorganic nanoparticles. In addition, fractionation effects between ²¹⁰Po and ²¹⁰Pb (or between ²¹⁰Pb and ⁷Be) could be quantified from their relative log K_c values on end-member sorbent components. Applications of both ²¹⁰Po–²¹⁰Pb and ⁷Be–²¹⁰Pb pairs as particle dynamics tracers could be more quantitative when the nature of the organic coatings is taken into account.

Link to full text: http://www.sciencedirect.com/science/article/pii/S0012821X15002964

Reference:

Weifeng Yang, Laodong Guo, Chia-Ying Chuang, Dorothea Schumann, Marin Ayranov, Peter H. Santschi. Adsorption characteristics of 210Pb, 210Po and 7Be onto micro-particle surfaces and the effects of macromolecular organic compounds.  Geochimica et Cosmochimica Acta, 2013, 107: 47-64.

Link: http://www.sciencedirect.com/science/article/pii/S0016703713000021