Study of the toluene absorption capacity and mechanism of ionic liquids using COSMO-RS prediction and experimental verification

As green solvents,ionic liquids(ILs)are quite suitable for the absorption of volatile organic compounds(VOCs)such as benzene and its homologues.However,solvent selection is the key to the VOC absorption process.In the present study,a rapid solvent screening tool,Conductor-like Screening Model for Real Solvents(COSMO-RS),was used to predict the solubility of toluene in 816 ILs.The effects of four structure characters,namely,the type and alkyl chain length of the cations and anions on the solubility of toluene were discussed.The following conclusions were drawn from the results:(1)ILs with pyrrolidinium-based cations showed better solubility than pyridinium-and imidazoliumbased ones.(2)The solubility of toluene in PF6-based ILs increased with the increasing alkyl chain length,while its solubility in Ac-based ILs exhibited the opposite trend.(3)Toluene showed greater solubility in Cl-based ILs than those based on other anions.(4)The solubility of toluene increased with the anion alkyl chain length.Ac-based ILs were chosen as the most promising potential solvents,and further studied to determine the relationship between various interaction energy parameters and toluene solubility.The results showed that the misfit energy played a dominant role during the absorption process.Furthermore,several ILs were selected for experimental verification of the predicted solubility behavior using liquid and gaseous toluene.The results demonstrated that COSMO-RS could be used to semi-quantitatively and qualitatively predict the solubility of toluene,and this model had promising prospects in screening ILs for VOCs absorption.In summary,this study provided a fundamental basis and practical data for the control and treatment of VOCs.

Corrosion behaviors and kinetics of nanoscale zero-valent iron in water:A review

Knowledge on corrosion behaviors and kinetics of nanoscale zero-valent iron(nZVI)in aquatic environment is particularly significant for understanding the reactivity,longevity and stability of nZVI,as well as providing theoretical guidance for developing a cost-effective nZVI-based technology and designing large-scale applications.Herein,this review gives a holistic overview on the corrosion behaviors and kinetics of nZVI in water.Firstly,Eh-pH diagram is introduced to predict the thermodynamics trend of iron corrosion.The morphological,structural,and compositional evolution of(modified-)nZVI under different environmental conditions,assisted with microscopic and spectroscopic evidence,is then summarized.Afterwards,common analytical methods and characterization technologies are categorized to establish time-resolved corrosion kinetics of nZVI in water.Specifically,stable models for calculating the corrosion rate constant of nZVI as well as electrochemical methods for monitoring the redox reaction are discussed,emphasizing their capabilities in studying the dynamic iron corrosion processes.Finally,in the future,more efforts are encouraged to study the corrosion behaviors of nZVI in long-term practical application and further build nanoparticles with precisely tailored properties.We expect that our work can deepen the understanding of the nZVI chemistry in aquatic environment.