Rain and snow water samples were collected from Sep. 2010 to Jun. 2011 at a semi-rural site in Ya'an, a city located in the rain-belt along the Tibetan Plateau, to characterize the chemical composition and the sources of precipitation. The collected samples were severely acidified with an annual volume-weighted mean (VWM) pH of 4.03 and an annual acid rain frequency of 79%. and were the most abundant ions, followed by Caand Mg 2+ . The acidity of samples was predominantly generated by H 2 SO 4 and HNO 3 , which were neutralized by and Ca 2+ as much as 65%. NH 3 played a major role in neutralizing the acid rain. The average ambient concentration of NH 3 was 174.2 μg/m 3 during sampling periods. Different source apportionment methods, including principle component analysis (PCA), enrichment factor (EF), correlation and back-trajectory analysis were used to track the sources of rainwater. The methods suggested that the pollutants in rainwater were from both local and long-distance transport (1:2.2), or they were from anthropogenic actions (86.4%), sea salts (8.1%) and crustal (5.5%) respectively.

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Background As potent antioxidants, anthocyanins can protect the body from free radicals. However, the traditional solvent extraction method has the disadvantages of requiring a high extraction temperature and long extraction time, so it is necessary to develop an efficient extraction method for anthocyanins. Results In this study, the technique of natural deep eutectic solvents (DESs) was applied to extract anthocyanins from purple perilla leaves with the aid of microwave‐ultrasonic assisted extraction (MUAE). The response surface methodology (RSM), based on the Box–Behnken design (BBD), predicted the maximum extraction yield of anthocyanins to be 619.62 mg (100 g)−1 under the following conditions: x1 (ultrasonic extraction power) = 357.25 W, x2 (time) = 25.62 min, and x3 (temperature) = 57.80 °C. The biological activity of the extract obtained was evaluated by examining its radical‐scavenging effect on 1,1‐diphenyl‐2‐picrylhydrazyl, hydroxyl radical, and superoxide anion radicals. Its bacteriostatic impact was investigated on four typical bacteria: Shewanella putrefaciens (S. putrefaciens), Pseudomonas fluorescens (P. fluorescens), Escherichia coli (E. coli), and Staphylococcus aureus (S. aureus). Conclusion The integrated extraction method of DESs with MUAE was efficient, energy‐saving, green, and sustainable. © 2022 Society of Chemical Industry.

A series of transition metal (M)-promoted carbonsilicon (CÀ MÀ Si; M = Mn, Fe, Co, Ni, Cu, Zn, Zr) solid acid catalysts with designated molar ratio of M/Si = 1 : 8 were fabricated and exploited for acetalization of benzaldehyde (BzH) with ethylene glycol (EG). The physical and chemical properties of these CÀ MÀ Si catalysts prepared by sol-gel method were characterized by various techniques, namely, SEM, EDS, TGA-DTG, BET, XRD, FTIR, XPS, and NH 3 -TPD. Among various examined acidic CÀ MÀ Si catalysts, the CÀ FeÀ Si catalyst exhibited the optimal catalytic activity with the benzaldehyde glycol acetal (BEGA) yield of 97.67 %, in excellent agreement with the value (97.88 %) predicted by the response surface methodology (RSM) based on a Box-Behnken design (BBD). CÀ FeÀ Si catalyst with the high catalytic activities and excellent stability and reusability may be ascribed to the suitable acidity and uniform surface distribution of active sites requisite for the acid-catalyzed acetalization reaction.