Health Risk Assessment of Workers' Exposure to Organic Compounds in a Tire Factory

This study focuses on a health risk assessment related to chemical exposure via inhalation for workers in a tire factory. Specifically, several volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) were measured in the four different points of the vulcanization unit. A chemical transport model was developed in order to better represent the workers' exposure to the chemicals. Then, a risk assessment methodology was employed to evaluate the potential adverse health effects of the chemicals according to their carcinogenicities. Concentrations measured near the milling machine and press in the vulcanization unit were generally higher than the respective occupational exposure limit values. The corresponding estimated cumulative cancer risks for the carcinogens at the each sampling point were higher than the designated acceptable risk level of 1 × 10^{? 4}. With respect to non-carcinogenic risks, the hazard indexes, both individually and cumulatively, were lower than the specified level of one. The high cancer risk estimated in this study suggests that the VOCs and SVOCs exposure for workers in the vulcanization unit should not be neglected. The results obtained in this study are valuable to plant managers, government officials, and regulators in the risk evaluation process.     

In Situ Formation of Co9S8 Quantum Dots in MOF‐Derived Ternary Metal Layered Double Hydroxide Nanoarrays for High‐Performance Hybrid Supercapacitors

Layered double hydroxides (LDHs) are promising cathode materials for supercapacitors because of the enhanced flow efficiency of ions in the interlayers. However, the limited active sites and monotonous metal species further hinder the improvement of the capacity performance. Herein, cobalt sulfide quantum dots (Co₉S₈‐QDs) are effectively created and embedded within the interlayer of metal‐organic‐frameworks‐derived ternary metal LDH nanosheets based on in situ selective vulcanization of Co on carbon fibers. The hybrid CF@NiCoZn‐LDH/Co₉S₈‐QD retains the lamellar structure of the ternary metal LDH very well, inheriting low transfer impedance of interlayer ions. Significantly, the selectively generated Co₉S₈‐QDs expose more abundant active sites, effectively improving the electrochemical properties, such as capacitive performance, electronic conductivity, and cycling stability. Due to the synergistic relationship, the hybrid material delivers an ultrahigh electrochemical capacity of 350.6 mAh g^?1 (2504 F g^?1) at 1 A g^?1. Furthermore, hybrid supercapacitors fabricated with CF@NiCoZn‐LDH/Co₉S₈‐QD and carbon nanosheets modified by single‐walled carbon nanotubes display an outstanding energy density of 56.4 Wh kg^?1 at a power density of 875 W kg^?1, with an excellent capacity retention of 95.3% after 8000 charge–discharge cycles. Therefore, constructing hybrid electrode materials by in situ‐created QDs in multimetallic LDHs is promising.