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DOI	10.5194/acp-22-3655-2022
	The impact of (bio-)organic substances on the ice nucleation activity of the K-feldspar microcline in aqueous solutions
	Klumpp, Kristian; Marcolli, Claudia; Peter, Thomas
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	3655
结束页码	3673
卷号	22 期号:5 页码:19
英文摘要	Potassium feldspars (K-feldspars), such as microcline, are considered key dust minerals inciting ice nucleation in mixed-phase clouds. Besides the high ice nucleation activity of microcline, recent studies also revealed a high sensitivity of microcline to interaction with solutes on its surface. Here, we investigate the effect of organic and bio-organic substances on the ice nucleation activity of microcline, with the aim to better understand the underlying surface interactions. We performed immersion freezing experiments with microcline in solutions of three carboxylic acids, five amino acids, and two polyols to represent these compound classes. By means of a differential scanning calorimeter we investigated the freezing of emulsified droplets of microcline suspended in various solutions. Depending on the type of solute, different effects were observed. In the case of carboxylic acids (acetic, oxalic, and citric acid), the measured heterogeneous onset temperatures, T-het, showed no significant deviation from the behavior predicted by the water activity criterion, T-het(a(w)) D T-melt(a(w) + Delta a(w)), which relates T-het with the melting point temperature T-melt via a constant water activity offset Delta a(w). While this behavior could be interpreted as a lack of interaction of the solute molecules with the surface, the carboxylic acids caused the fraction of heterogeneously frozen water, F-het(a(w)), to decrease by up to 40% with increasing solute concentrations. In combination, unaltered T-het(a(w)) and reduced F-het(a(w)) suggest that active sites were largely deactivated by the acid molecules, but amongst those remaining active are also the best sites with the highest T-het. A deviation from this behavior is citric acid, which showed not only a decrease in F-het, but also a decrease in T-het of up to 4K for water activities below 0.99, pointing to a depletion of the best active sites by interactions with the citrate ions. When neutralized solutions of the acids were used instead, the decrease in F-het became even more pronounced. The slope of T-het(a(w)) was different for each of the neutralized acid solutions. In the case of amino acid solutions, we found a decrease in T-het (up to 10 K), significantly below the Delta a(w) criterion, as well as a reduction in F-het (up to 60 %). Finally, in the case of the investigated polyols, no significant deviation of T-het from the Delta a(w) criterion was observed, and no significant deviation of F-het in comparison to a pure water suspension was found. Furthermore, we measured the effects of aging on the ice nucleation activity in experiments with microcline suspended in solutions for up to 7 d, and tested the reversibility of the interaction with the solutes after aging for 10 d. For citric acid, an ongoing irreversible degradation of the ice nucleation activity was observed, whereas the amino acids showed completely reversible effects. In summary, our experiments demonstrate a remarkable sensitivity of microcline ice nucleation activity to surface interactions with various solutes, underscoring the importance of the history of such particles from the source to frozen cloud droplets in the atmosphere.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000772233300001
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/273434
作者单位	Swiss Federal Institutes of Technology Domain; ETH Zurich
推荐引用方式 GB/T 7714	Klumpp, Kristian,Marcolli, Claudia,Peter, Thomas. The impact of (bio-)organic substances on the ice nucleation activity of the K-feldspar microcline in aqueous solutions[J],2022,22(5):19.
APA	Klumpp, Kristian,Marcolli, Claudia,&Peter, Thomas.(2022).The impact of (bio-)organic substances on the ice nucleation activity of the K-feldspar microcline in aqueous solutions.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(5),19.
MLA	Klumpp, Kristian,et al."The impact of (bio-)organic substances on the ice nucleation activity of the K-feldspar microcline in aqueous solutions".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.5(2022):19.