Guodong Liu,Xinxin He,Xiaoya Liu,Donghui Ma,Jun Tang,Zongmin Ma,Yanjun Li,Jun Liu
This research explores the desorption mechanism and thermal stability of octadecyltrichlorosilane (OTS, CH 3 (CH 2 ) 17 SiCl 3 ) coating on quartz slides and in alkali-metal vapour cells. The morphological thermal-changes, energy dissipation diversity, and anti-relaxation characteristic of OTS coatings before and after exposure to Cs atoms by Fourier transform infrared spectroscopy, water contact angle measurement, atomic force microscopy imaging, collision energy dissipation analysis, and free induction decay of Cs atoms are measured systematically. The results show that the OTS coatings exhibit the best thermal stability under the specific process conditions, and the homogeneous and dense structure makes the adsorption of alkali-metal atoms more stable, which effectively reduces surface energy dissipation and prolongs the relaxation time of Cs atoms. The study provides certain reference for efficient anti-relaxation coating fabrication and coated cell application.
Microplastics (MPs) in the environment usually undergo extensive weathering and can transport pollutants to organisms once being ingested. However, the transportation mechanism and effect of aging process are poorly understood. This study systematically investigated the desorption mechanisms of pharmaceuticals from pristine and aged polystyrene (PS) MPs under simulated gastric and intestinal conditions of marine organisms. Results showed that the increased desorption in stomach mainly depended on the solubilization of pepsin to pharmaceuticals and the competition for sorption sites on MPs via π-π and hydrophobic interactions. However, high desorption in gut relied on the solubilization of intestinal components (i.e. bovine serum albumin (BSA) and bile salts (NaT)) and the competitive sorption of NaT since the enhanced solubility increased the partition of pharmaceuticals in aqueous phase. Aging process suppressed the desorption of pharmaceuticals because aging decreased hydrophobic and π-π interactions but increased electrostatic interaction between aged MPs and pharmaceuticals, which became less affected by gastrointestinal components. Risk assessment indicated that the MP-associated pharmaceuticals posed low risks to organisms, and warm-blooded organisms suffered relatively higher risks than cold-blooded ones. This study reveals important information to understand the ecological risks of co-existed MPs and pollutants in the environment.
Purpose In order to investigate the desorption effect and mechanism of petroleum from petroleum contaminated soil (PCS) in surfactant solution (SAA-solution). Method In this study, the desorption effect of SAA-solution cleaning of PCS was systematically analyzed by using orthogonal experiments. In addition, the petroleum mechanism of desorption from the PCS surface was further explored by kinetic and thermodynamic studies. Results The results indicated that the petroleum removal efficiency (Re) gradually decreased with the increase of PCS particle size and PCS aging time. The highest petroleum Re was 82.13% under optimum conditions. Subsequently, FT-IR and petroleum component analysis showed the petroleum light components were easily removed from PCS, while the petroleum heavy components limited the desorption of petroleum. The kinetic studies revealed that the petroleum desorption was well depicted by the pseudo-first-order kinetic model, and the desorption rate increased with the decrease of PCS particle size. Meanwhile, the petroleum desorption equilibrium was well described by the Langmuir isotherm model and proceeded by a chemical mechanism. The thermodynamic studies demonstrated that the petroleum desorption from PCS was a viable, spontaneous, and endothermic process. Conclusion The study provided theoretical guidance to apply SAA-solution cleaning industrial PCS. Graphical Abstract
危险品化学品经营许可证（带存储）