With a growing awareness of environmental protection, the dust pollution caused by automobile foundry work has become a serious and urgent problem. This study aimed to explore contamination levels and health effects of automobile foundry dust. A total of 276 dust samples from six types of work in an automobile foundry factory were collected and analysed using the filter membrane method. Probabilistic risk assessment model was developed for evaluating the health risk of foundry dust on workers. The health risk and its influencing factors among workers were then assessed by applying the Monte Carlo method to identify the most significant parameters. Health damage assessment was conducted to translate health risk into disability-adjusted life year (DALY). The results revealed that the mean concentration of dust on six types of work ranged from 1.67 to 5.40 mg/m3. The highest health risks to be come from melting, cast shakeout and finishing, followed by pouring, sand preparation, moulding and core-making. The probability of the risk exceeding 10−6 was approximately 85%, 90%, 90%, 75%, 70% and 45%, respectively. The sensitivity analysis indicated that average time, exposure duration, inhalation rate and dust concentration (C) made great contribution to dust health risk. Workers exposed to cast shakeout and finishing had the largest DALY of 48.64a. These results can further help managers to fully understand the dust risks on various types of work in the automobile foundry factories and provide scientific basis for the management and decision-making related to health damage assessment.
CNT-TiO2 composite is used to activate PMS under UV-light assistance.Superior performance is due to the enhanced electron-transfer ability of CNT.SO4•−, •OH and 1O2 play key roles in the degradation of organic pollutants. In this work, a UV-light assisted peroxymonosulfate (PMS) activation system was constructed with the composite catalyst of multi-walled carbon nanotubes (CNT) - titanium dioxide (TiO2). Under the UV light irradiation, the photoinduced electrons generated from TiO2 could be continuously transferred to CNT for the activation of PMS to improve the catalytic performance of organic pollutant degradation. Meanwhile, the separation of photoinduced electron-hole pairs could enhance the photocatalysis efficiency. The electron spin resonance spectroscopy (EPR) and quenching experiments confirmed the generation of sulfate radical (SO4•−), hydroxyl radical (•OH) and singlet oxygen (1O2) in the UV/PMS/20%CNT-TiO2 system. Almost 100% phenol degradation was observed within 20 min UV-light irradiation. The kinetic reaction rate constant of the UV/PMS/20%CNT-TiO2 system (0.18 min−1) was 23.7 times higher than that of the PMS/Co3O4 system (0.0076 min−1). This higher catalytic performance was ascribed to the introduction of photoinduced electrons, which could enhance the activation of PMS by the transfer of electrons in the UV/PMS/CNT-TiO2 system. 相似文献
Heterotrophic cultivation caused high level of ROS and high lipids accumulation.HMTC is the best culture strategy for improving the microalgal biomass.Chlorella sp. HQ had great nutrient removal capacity under five culture strategies. The effects of cultivation strategies (including autotrophic cultivation (AC), heterotrophic cultivation (HC), fed-batch cultivation (FC), heterotrophic+ autotrophic two-stage cultivation (HATC), and heterotrophic+ mixotrophic two-stage cultivation (HMTC)) on the growth and lipid accumulation of Chlorella sp. HQ and its total nitrogen (TN) and total phosphorus (TP) removal in secondary effluent were investigated in column photoreactors. The results showed that the TN and TP removal rates ranged between 93.72%–95.82% and 92.73%–100%, respectively, under the five different strategies. The microalgal growth potential evaluated by the maximal growth rate (Rmax) was in the order of HMTC>HC>FC>AC>HATC. The values of biomass, total lipid yield, triacylglycerols (TAGs) yield, and total lipid content of the microalga cultivated in the last 5 d increased significantly, but the TAGs productivities of the five strategies were lower than those in the first 7 d. Compared with all the other cultivation strategies, the TAGs productivity and yield after 12 d of cultivation under the heterotrophic condition reached the highest values accompanying the highest level of intracellular reactive oxygen species (ROS), in which the TAGs yield reached 40.81 mg/L at the end of the cultivation period. The peaks in TAGs yield and ROS level suggested that HC was beneficial for lipids accumulation via regulating the cellular redox status and exerting ROS stress on microalgal cells. In summary, HMTC was the best cultivation strategy for improving the microalgal biomass and HC was the best strategy for microalgal TAGs accumulation to produce biodiesel. 相似文献
Resin adsorption and subsequent electrodeposition were used for nickel recovery.Treated wastewater can meet the Electroplating Pollutant Discharge Standard.The spent resin is completely regenerated by 3 BV of 4% HCl solution.95.6% of nickel in concentrated eluent was recovered by electrodeposition. Effective recovery of high-value heavy metals from electroplating wastewater is of great significance, but recovering nickel ions from real electroplating wastewater as nickel sheet has not been reported. In this study, the pilot-scale fixed-bed resin adsorption was conducted to recover Ni(II) ions from real nickel plating wastewater, and then the concentrated Ni(II) ions in the regenerated solution were reduced to nickel sheet via electrodeposition. A commercial cation-exchange resin was selected and the optimal resin adsorption and regeneration conditions were investigated. The resin exhibited an adsorption capacity of 63 mg/g for Ni(II) ions, and the average amount of treated water was 84.6 bed volumes (BV) in the pilot-scale experiments. After the adsorption by two ion-exchange resin columns in series and one chelating resin column, the concentrations of Ni(II) in the treated wastewater were below 0.1 mg/L. After the regeneration of the spent resin using 3 BV of 4% (w/w) HCl solution, 1.5 BV of concentrated neutral nickel solution (>30 g/L) was obtained and used in the subsequent electrodeposition process. Using the aeration method, alkali and water required in resin activation process were greatly reduced to 2 BV and 3 BV, respectively. Under the optimal electrodeposition conditions, 95.6% of Ni(II) in desorption eluent could be recovered as the elemental nickel on the cathode. The total treatment cost for the resin adsorption and regeneration as well as the electrodeposition was calculated. 相似文献