| Ozone is an oxidant commonly used in water treatment processes. And, ozone is widely used in contaminant water remediation and pretreatment and treatment processes of high concentration organic wastewater. However, the characteristic of easy to decompose of ozone makes ozone can only produced in situ, limit its application in in-situ remediation field. Therefore, study on the ozone inclusion oxidation technique to prolong ozone existing time and keep the selective oxidizing property is significant, which to improve the oxidizing processes and expand the application field of ozonation.The paper set ozonation process as the research object, introduce cyclodextrin into ozonation process to form cyclodextrin/ozone inclusion complex. By studying the formation process of cyclodextrin/ozone inclusion complex, inclusion and reaction processes between the inclusion complex and indicator and the effects of removal of pharmaceutical and personal care products(PPCPs), the following main results are obtained:(1) Experimental study of preparison and oxidizing properties showed that the oxidizing abilities of types of cyclodextrins after ozonation were different. The study indicated that derivative of ?-cyclodextrin: hydroxypropyl-?-cyclodextrin(Hp-?-CD) is the best host molecule to form inclusion complex with ozone. Through the reaction between Hp-?-CD/ozone inclusion complex and indicator(indigo trisulfonate), it was found that compared to the ozonation process, Hp-?-CD/ozone inclusion complex oxidizing process was more sustainable, in acidic condition, the oxidizing process would last for mare than one week. Spectrographic characteristic of Hp-?-CD after ozonation showed that after ozonation,the absorbance of Hp-?-CD solution increased significantly in the range of 190 - 400 nm,and the spectrum also had a peak in the maximum absorbance of ozone, confirmed that the Hp-?-CD/ozone inclusion complex formed.(2) The experimental study of Absorption features of Hp-?-CD/ozone inclusion complex solution and reaction with indicator showed that scan spectra of different concentrations of Hp-?-CD/ozone inclusion complex solution had almost the same shape,indicated that formed the same substance after ozonation. Aqueous ozone can react with ABTS as 1:1 stoichiometry, ABTS lost one electron after ozonation to form a stable green ABTS + cation. The absorbance of ABTS+ cation had five obvious peaks in 405?415?650?732?820 nm respectively. In practice, an appropriate peak can be selected in case of possible interference caused by other oxidants. ABTS could react both with aqueous ozone and Hp-?-CD/ozone inclusion complex solution, thus can be used as a medium to measure the oxidizing ability of Hp-?-CD/ozine inclusion complex. Quantitative results showed that there was no obvious linear relationship between oxidizing ability of Hp-(3-CD/ozone inclusion complex and aqueous ozone. The oxidizing ability of Hp-?-CD/ozone inclusion complex affected with many factors, except Hp-?-CD/ozone inclusion complex concentrations. By the large, inclusion ratio between Hp-?-cyclodextrin and ozone was determined to be 1:2.(3) Kinetics research of Hp-?-CD/ozone inclusion complex solution and ABTS showed that the reaction between Hp-?-CD/ozone inclusion complex solution and ABTS was not quite fit first or second order reaction, but a complicated reaction. By using splitting kinetics method, the whole reaction can divided into fast reaction stage, moderate reaction stage and slow reaction stage. Each stage reaction rates were simulated by Aquasim 2.0 software, and the results indicated that the slow reaction rate was kobs=-4E-05L/?mol/h, moderate stage reaction rate was kobs=-2E-04L/?mol/h, and the reaction rate of fast stage was kobs=-3.06E-02L/?mol/h, there were three orders of magnitudes over fast and slow reaction rate.(4) The research on application of Hp-?-CD/ozone inclusion complex showed that transferred ozone dose would significantly affected removal efficiencies of PPCPs by Hp-?-CD/ozone inclusion complex. With the same transferred ozone dose, the removal efficiencies of PPCPs by aqueous ozone was better than Hp-?-CD/ozone inclusion complex,however, after saturated ozonation, Hp-?-CD/ozone inclusion complex had a better PPCPs removal efficiencies than aqueous ozone. Under the saturated ozonation condition, most selected PPCPs were removed effectively. Removal efficiencies were significantly decreased with the increase of pH value, and the removal efficiencies were not significantly affected by temperature changes. During the process of degradation of PPCPs by Hp-?-CD/ozone inclusion complex, the pH in solution was decrease, indicated that some acidic compounds formed. The reaction products detected by UPLC/MS/MS showed that most reaction products were low molecular weight organic matters, indicated that broken bonds occurred in the reaction processes and formed low molecular weight organic matters. The TOC value change was not obviously observed, indicated that the main approaches of PPCPs degradation was oxidized to ow molecular weight organic matters, mineralization was not obvious.The results showed that Hp-?-CD introduced in ozonation, improved traditional ozonation process, and the formed inclusion complex also has powerful sustainable oxidizing ability. This Hp-?-CD/ozone inclusion complex had a potential application on in-situ contaminants removal in water. This study created a new approach in the field of in-situ remediation in water by ozonation. |
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