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Background The serious air pollution of highway toll booths poses a high occupational exposure risk to toll collectors. It is urgent to develop purification methods suitable for airborne particles and microbial pathogens in highway toll booths. Objective To verify the purification effect of low temperature plasma air purifiers on airborne particles and microbes in highway toll booths. Methods Based on controlled-intervention design, we selected three toll booths in an expressway toll station as on-site experimental locations for 6 d (no-intervention period: the low-temperature plasma purifier was turned off in the first three days; intervention period: the purifier was turned on from 9:00 to 17:00 in the following three days). The indoor and outdoor PM2.5 and PM10 concentrations were continuously monitored during the study. At 9:00, 12:00, and 17:00 of every day during the experiment, indoor and outdoor air samples were collected to analyze the concentration of airborne culturable colonies with a plankton sampler. Airborne particle samples were collected in the outermost exit continuously from 9:00 to 17:00 every day during the experiment using a medium flow particulate sampler, and the species and relative abundance of fungi and bacteria contained in the samples were analyzed by gene sequencing. Independent-sample t test was used to compare the concentration of indoor PM2.5, PM10, and culturable colonies between the intervention period and the non-intervention period. α diversity analysis, β diversity analysis, and t test were used to compare the diversity and relative abundance of specific species of bacteria and fungi, as well as typical pathogenic bacteria and fungi in the samples between the non-intervention period and the intervention period to reflect the purification effect of low temperature plasma air purifier on airborne PM2.5, PM10, and microorganisms. Results During the intervention period, the mean indoor concentrations of PM2.5, PM10, and culturable colonies were lower than those of the no-intervention period (P<0.01 or P<0.001). The ratios of indoor to outdoor concentration (I/O) of PM2.5 and PM10 during the intervention period were significantly lower than those of the no-intervention period (P<0.001), except the I/O of culturable colonies. Compared with the average concentration at 9:00, the average cleaning rates at 12:00 and 17:00 for PM2.5 were 49.0% and 46.1%, for PM10 were 49.7% and 45.4%, for airborne culturable colonies were 50.8% and 49.9%, respectively. The β diversity analysis showed that there were significant differences in composition at the level of species of bacteria, and at the levels of genus and species of fungi between the intervention and the no-intervention periods. The relative abundances of 10 species of bacteria such as Lactobacillus and 7 species of fungi such as Torula in the intervention period were significantly lower than those in the non-intervention period, but the relative abundances of fungi such as unclassified_f_cladosporiaceae, trichomerium, and cercospora were higher (P<0.05). For typical pathogenic bacteria, the relative abundances of Lactobacillus and Clostridium_sensu_stricto_1 during the intervention period were 73.5% and 86.9% lower than those in the no-intervention period, and the relative abundance of Talaromyces was 53.5% lower (P<0.05). Conclusion Low temperature plasma air purifier has a good purification effect on indoor PM2.5, PM10, and culturable colonies in highway toll booths, and likely a limited effect on some fungi.
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Objective@#To study the effect of activated carbon on the purification of formaldehyde in the clean workshop return air purification device and its influencing factors.@*Methods@#From May to June 2018, choosed 4 different commercial activated carbons (bamboo charcoal, 1-3 mm, 3-5 mm; coconut shell charcoal, 6-12 mesh, 8-16 mesh) to make 5 types of activated carbon purification net. In the simulated clean plant laboratory, the detection of occupational disease hazards was used to test the purification effect of different types of activated carbon purification nets on formaldehyde.@*Results@#The purification effect of different types of activated carbon increased with the prolongation of purification time, and the difference was statistically significant (P<0.05) . Compared with other types of activated carbon, coconut shell charcoal (8-16 mesh, double layer) had the best purification effect, 15 min and 30 min purification efficiency was 58.72% and 85.20% respectively, and the difference was statistically significant (P<0.05) . The purification effect of double-layer coconut shell charcoal was better than single layer (P<0.05) . The purification effect of double-layer coconut shell charcoal (8-16 mesh) was better than double-layer coconut shell charcoal (6-12 mesh) , the difference was statistically significant (P<0.05) . Coconut shell charcoal (8-16 mesh, double layer) had better purification effect than bamboo charcoal (P<0.05) .@*Conclusion@#Different specific surface area, particle size, and thickness of activated carbon have a certain effect on the purification effect of formaldehyde, and its selection has a certain significance in improving the occupational health protection level in the clean plant, solving the safe use of return air and reducing energy consumption.
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Objective The separation and purification of anthocyanin from blueberry was studied to determine the optimum purification conditions. Methods Static adsorption and desorption analytical test was conducted to screen the best macroporous resin from HPD-600, HPD-100A, DM130, D4020, and D3520 for purification of anthocyanins from blueberry. Effects of the sample liquid concentration, pH, adsorption flow rate, eluent ethanol concentration, eluent ethanol amount, and elution flow rate were investigated through dynamic adsorption-desorption test by single factor and orthogonal experiments. Results D3520 resin was the most effective resin for adsorption and desorption of anthocyanins from blueberry, when the amount of macroporous resin (g) and the amount of anthocyanin from blueberry (mL) was 1:5. The optimal conditions were as follows: The concentration of sample was 1.0 mg/mL, adsorption flow rate was 2.0 mL/min, and sample solution pH value was 3. Under the optimal conditions, eluent ethanol concentration 70%, elution flow rate 2.0 mL/min, eluent ethanol amount 60 mL, and the adsorption rate and desorption rate can reach 92.82% and 91.58% respectively. Conclusion The color value of purified products under the optimized conditions was increased by 11 times; The purity fraction of anthocyanin was 96.17% and the purity was increased by 5 times; And the yield of anthocyanin was 14.271%. This process effectively improves the efficiency of anthocyanin from blueberry purification, which is suitable for the future production of anthocyanin from blueberry.