Efficient Electrochemical Oxidation of Chloramphenicol by Novel Reduced TiO2 Nanotube Array Anodes: Kinetics, Reaction Parameters, Degradation Pathway and Biotoxicity Forecast.

The key component of electrochemical advanced oxidation technology are high-efficiency anodes, and highly efficient and simple-to-prepare materials have generated a lot of interest. In this study, novel self-supported Ti3+-doped titanium dioxide nanotube arrays (R-TNTs) anodes were successfully prepared by a two-step anodic oxidation and straightforward electrochemical reduction technique. The electrochemical reduction self-doping treatment produced more Ti3+ sites with stronger absorption in the UV-vis region, a band gap reduction from 2.86 to 2.48 ev, and a significant increase in electron transport rate. The electrochemical degradation effect of R-TNTs electrode on chloramphenicol (CAP) simulated wastewater was investigated. At pH = 5, current density of 8 mA cm-2, electrolyte concentration of 0.1 M sodium sulfate (Na2SO4), initial CAP concentration of 10 mg L-1, CAP degradation efficiency exceeded 95% after 40 min. In addition, molecular probe experiments and electron paramagnetic resonance (EPR) tests revealed that the active species were mainly •OH and SO4-, among which •OH played a major role. The CAP degradation intermediates were discovered using high-performance liquid chromatography-mass spectrometry (HPLC-MS), and three possible degradation mechanisms were postulated. In cycling experiments, the R-TNTs anode demonstrated good stability. The R-TNTs prepared in this paper were an anode electrocatalytic material with high catalytic activity and stability, which could provide a new approach for the preparation of electrochemical anode materials for difficult-to-degrade organic compounds.

Chromatographic fingerprint combined with content of asperosaponin VI and antioxidant activity for quality evaluation of wine-fried Dipsaci Radix.

Dipsaci Radix, the dry root of Dipsacusasper Wall. ex Henry, is a commonly used traditional Chinese medicine (TCM). A novel comprehensive method was proposed for quality evaluation of wine-fried Dipsaci Radix by an integrated data including three aspects of information: high performance liquid chromatography (HPLC) fingerprint, asperosaponin VI content and antioxidant activity (AA). Various indicators including fingerprint similarity, asperosaponin VI content and AA were respectively employed for quality assessment of processed Dipsaci Radix samples. Results showed that considerable differences existed in quality of processed samples with different processing conditions according to three indicators. Among the factors affecting quality of wine-fried Dipsaci Radix, heating temperature was the most influential factor based on analysis of variance (ANOVA), and should be cautiously controlled. The three evaluation indicators respectively used for optimization of processing technology suggested different optimal conditions of wine-frying. Therefore, a combined indicator based on three evaluation indicators was used for determination of optimal processing condition. Multivariate statistical methods such as Hierarchical Clustering Analysis (HCA) and Principal Components Analysis (PCA) were both employed to classify the processed samples for quality evaluation. To more comprehensively evaluate the quality of wine-fried Dipsaci Radix, HPLC fingerprint combined with content of asperosaponin VI and AA may be a reasonable and practical approach.