ABSTRACT
The emissions of the catering industry are important sources of air pollution in megacities in China. A total of 41 restaurants in Beijing were selected as the sampling sites to evaluate the contribution of the catering industry to megacity air pollution. The original emissions load of cooking fume, particulate matter, and non-methane hydrocarbon (NMHC) were studied via field tests for different types of restaurants. The results showed that the cooking fume, particulate matter, and NMHCs generated from the kitchen were 1.93, 6.6, and 10.9 mg·m-3, respectively. An evaluation method based on working days was developed. Considering the total number of restaurants in Beijing, the original emission loads of 2019 were calculated. The cooking fume, particulate matter, and NMHC emissions were 5512, 18849, and 6169 t, respectively. The Pearson numbers of the cooking fume emission and particular matter emission from Sichuan and Hunan cuisine, Roast Duck, Grill and Barbecue, and Chinese Home-Style cuisine were all above 0.6, which indicated a high level of correlation between the cooking fume emission and particular matter emission. Notably, the Pearson numbers of Sichuan and Hunan cuisine and Roast Duck were both higher than 0.8, which indicates a strong correlation between the cooking fume emission and particular matter emission.
ABSTRACT
In this study we investigated the enrichment ability of oxidized multiwalled carbon nanotubes (MWCNTs) and established a new method for the determination of trace cadmium in environment with flame atomic absorption spectrometry. The MWCNTs were oxidized by potassium permanganate under appropriate conditions before use as preconcentration packing. Parameters influencing the recoveries of target analytes were optimized. Under optimal conditions, the target analyte exhibited a good linearity (R2=0.9992) over the concentration range 0.5-50 ng/ml. The detection limit and precision of the proposed method were 0.15 ng/ml and 2.06%, respectively. The proposed method was applied to the determination of cadmium in real-world environmental samples and the recoveries were in the range of 91.3%-108.0%. All these experimental results indicated that this new procedure could be applied to the determination of trace cadmium in environmental waters.
Subject(s)
Cadmium/analysis , Nanotubes, Carbon/chemistry , Potassium Permanganate/chemistry , Spectrophotometry, Atomic/methods , Cadmium/chemistry , Protons , Reproducibility of ResultsABSTRACT
A rapid, simple and sensitive method was demonstrated for the determination of phenolic compounds in water samples by alternating-current oscillopolarographic titration. With the presence of sulfuric acid, phenol could be transferred into a nitroso-compound by reacting with NaNO2. The titration end-point was obtained by the formation of a sharp cut in the oscillopolarographic with infinitesimal NaNO2 on double platinum electrodes. The results showed that phenol concentration had an excellent linear relationship over the range of 4.82 x 10(-6)-9.65 x 10(-3) mol/L, the RSD of the proposed method was lower than 1.5%, and the spiked recoveries of three real water samples were in the range of 95.6%-106.9%.
