Collaborative Research: Sorption Reversibility of Hydrophobic Compounds in Geosorbents Investigated with Model Sorbents

[122761 . Pignatello]本研究的目的是对两种吸附-解吸滞后现象有一个基本的认识。这些包括热力学不可逆吸附，其中吸附和解吸遵循不同的微观途径，以及由于吸附物的非生物表面催化化学转化而导致的滞后性，其中产物仍然不可逆转地与固体结合。本研究将集中于自然环境下有机化合物的主要热力学吸附剂：大分子有机碳（腐殖质）和显微有机碳（黑碳）。吸附实验将在表征良好的模型吸附剂上进行，其行为比天然吸附剂更能与机理联系起来。吸附和解吸数据将用于计算不可逆指数，以量化不可逆吸附滞后。非反应性测试化合物将是三氯甲烷、三氯乙烯、苯和萘，反应性测试化合物将是苯酚、儿茶酚和邻苯三酚。对迟滞的理解对于模拟化学物质的命运、定义土壤或沉积物质量标准、开发修复技术以及制定修复后可接受的污染水平标准至关重要。这是康涅狄格州农业实验站（BES-0122761）和伦斯勒理工学院（BES-0122863）之间的合作研究资助。＊＊＊

0122761 Pignatello The objective of this research is to obtain a fundamental understanding of two kinds of adsorption-desorption hysteresis. These include thermodynamically irreversible sorption, in which adsorption and desorption follow different microscopic pathways, and hysteresis due to abiotic surface-catalyzed chemical transformation of the adsorbate where the products remain irretrievably bound to the solid. This research will focus on the principle thermodynamic sorbents of organic compounds in natural settings: macromolecular organic carbon (humic substances) and micrographitic OC (black carbon). Sorption experiments will be performed on well-characterized model sorbents, whose behavior can be better related to mechanism than whole natural geosorbents. Adsorption and desorption data will be used to compute an irreversibility index to quantify irreversible sorption hysteresis. Non-reactive test compounds will be trichloromethane, trichloroethene, benzene, and naphthalene, and the reactive test compounds will be phenol, catechol, and pyrogallol. An understanding of hysteresis is crucial to modeling a chemical's fate, defining soil or sediment quality criteria, developing remediation technologies, and setting standards for acceptable levels of contamination after remediation. This is a collaborative research grant between Connecticut Agricultural Experiment Station (BES-0122761) and Rensselaer Polytechnic Institute (BES-0122863). ***