| In recent years, every year the economic loss caused by SO2 and acidic rain pollution in our country can be amounting to hundreds of billions of dollars due to crops, forests and human health aspects. It has become an important factor restricting China’s national economic and social development. With the aggravation of the pollution of SO2 on crop leaf, the photosynthetic pigments, stomata, cell membrane, antioxidant enzymes, and root growth are greatly influenced. How to avoid the influence of the sulfur oxide, such as SO2 on crops? Eliminating pollution from the source is probably an effective method. Organic sulfide is one of the main sulfur in fuels; the removal of organic sulfur in fuel has important theoretical significance and application value. The national requirement on sulfur content in fuels has become more and more strict. Most countries are proposed to solve the vehicle tail gas pollution from the sources, namely, the adoption of new technology to reduce sulfur content in fuels. Extractive desulfurization and oxidation/extraction coupling desulfurization technology are new desulfurization technologies that are very promi-sing. However, they are mainly based on the volatile organic solvents, which are dangerous and causes serious environmental pollution. Therefore, it is important to investigate the new green extractants for the specific process. Ionic liquids(ILs) and deep eutectic solvents(DESs) are new types of solvents, which are considered as green solvents to replace volatile organic ones. Their excellent physicochemical properties have received widespread attention. The purpose of this study is to review the influence of SO2 on crops systematically. Then the effect of SO2 on leaf was probed. To improve the crop growth environment and provide a good environment for the growth of crops, deep removal of organic sulfide in fuels was investigated by using extraction or oxidation/extraction process. The main conclusions are as follows:(1) Protic ionic liquids can realize the removal of organic sulfur in fuels efficiently. Cations and anions both influence desulfurization process greatly. Cations have more effect on the desulfurization process. When the mass ratio of protic ionic liquids and fuels was 4:1, the optimal desulfurization efficiency can be up to 88.0%. After multiple times of extraction, the sulfur content can be reduced significantly in fuels and deep desulfurization was realized. From the repeated use of the ionic liquids, the desulfurization efficiency of the ionic liquids decreased gradually. To be noted, the recycling of protic ionic liquids can be realized by vacuum distillation. From mechanism study, the hydrogen bonding interaction is the main driving force of the extraction process.(2) Through the proper choice of different hydrogen bond donor and acceptor, series of deep eutectic solvents were designed and synthesized, and their applications in desulfurization of fuels were investigated. For the simple extractive desulfurization process, the removal effic-iency can be up to 71.1% with a single cycle, which is much higher than that of the existing ILs. At the same time, hydrogen bond acceptors(HBD) and hydrogen bond donor(HBA) both influence the desulfurization process, but HBA have more influences. To achieve the target ofthe deep desulfurization of fuels, DESs were used as ‘three agents in one’, namely catalyst, solvent and extractant, were investigated. Acidic DESs formed by Choline chloride and Tetrabutylammonium Chloride with p-toluene sulfonic acid(p-TSA) can be used to achieve ‘one pot’ deep desulfurization of fuels. Their desulfurization efficiency can reach above 99.9%. Hydrogen bond donor and acceptor both have influence on the oxidation/extraction process. The acidity of DESs has a great influence on the desulfurization process; the acidity has positive correlation with its oxidation/desulfurization efficiencies. With Ch Cl/p-TSA as extracant, the m(H2O2): m(Oil) is 0.05:1, the extraction efficiency is as high as 99.9%. When using TBAC/p-TSA as extractant, m(H2O2): m(Oil) is 0.3:1, the extraction efficiency can achieve 99.9%. 1H NMR, IR, GC-MS and EPR was used to investigate the mechanism of the oxidation/extraction coupling desulfurization process. Research shows that the process follows the pathway of the extraction and oxidation, that is to say, BT is extracted into DESs phase firstly, then is oxidized to BTO2. Finally, BTO2 is extracted by DESs.(3) Based on the eutectic theory, alcohol based extractants were selected as hydrogen bond donor, deep desulfurization of fuels can be achieved through this specific process. The desulfurization process is affected by many factors, such as the system temperature, equilibrium time, initial concentration of sulfur, stirring speed, extractants dosage. Research shows that high temperature is not conducive to the desulfurization process, the extraction efficiency is higher at room temperature. The dosage of PEG has positive influence on extraction efficiency of the desulfurization process, when the fuels: PEG comes to 1:1, the extraction efficiency can reach 99.9%. Finally, through the 1H NMR and FT-IR study, the extraction mechanism was revealed and listed as follows. The hydrogen bonding formed between sulfur atoms in hydroxyl and DBT on PEG, forming a deep eutectic solvent, which leads to a higher extraction efficiency.(4) Sulfur oxides, such as SO2 have great influence on crop leaves with great acute hazard; high concentration of SO2 on crop leaves with great acute hazard than low concentration one. The contact time and gas concentration of SO2 are the two main factors that determine the plant injury. The higher of the SO2 concentration, the more obvious of the leaf necrosis spot and the greater of the injured areas. The longer of the blades, the more serious of the injury. Therefore, it has theoretical significance and application value to carry out research on sulfur removal.The research will provide a new theory, new method and new technology for removal of organic sulfide in fuels. |
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