Phosphorus Adsorption-Desorption on Airborne Dust and Desert Particles in Natural Water

摘要

Abstract -We investigated phosphorus (P) adsorption-desorption behaviors on the airborne dust (Y1，collected during a sandstorm in Hohhot) and the desert particles (Y2、Y3 and Y4，collected from the deserts in western Inner Mongolia，source of the sandstorm) in their affected waters (Yellow River and Bohai Sea) in phosphorus cycle. The fitted experimental data using the improved Langmuir isotherm adsorption models show that the maximum P adsorption capacity Qmax are in the range of 68.493 ~ 357.143 mg•kg-1, with the largest value observed on Y3 (Juyanhai Lake particulate). The Qmax is remarkably correlated with organic matter of the particulates; The zero equilibrium phosphorus concentration EPC0 of P adsorption on Y1 in Yellow River is lower than P concentration in the overlying water (0.028mg•L-1 < 0.0469mg•L-1), while the EPC0 of particulates （Y1～Y4） in Bohai Sea water are higher than the P concentration in their corresponding water. This shows that airborne dust Y1, as a sink, adsorb P at Qingshuihe segment of Yellow River; Meanwhile, it is also as a source to releases P to Bohai Sea. There is a desorption phenomenon in P exchange between the particulates (Y1 ~ Y4) and Bohai Sea.