Synergistic heat/UV activated persulfate for the treatment of nanofiltration concentrated leachate.

Nanofiltration concentration leachate is a high concentration organic wastewater with low biodegradability and high toxicity. To explore the feasibility of a combined Heat/UV activated persulfate process on nanofiltration concentrated leachate, the effects of persulfate concentration, initial solution pH before reaction, UV-lamp power and reaction temperature on the removal of organic pollutant were systematically investigated. Results indicated that the maximum rate of chemical oxygen demand (COD), ammonia-nitrogen (NH3-N) and absorbance of organic matter under UV light at 254 nm (UV254) removal from the leachate were 65.4%, 51.4% and 98.1%, respectively, at a persulfate concentration of 18 g L-1, initial solution pH before reaction of 9.0, UV-lamp power of 60 W and temperature of 80 °C. The results of three-dimensional fluorescence and UV254 showed that the removal rates of humic substances contained in the nanofiltration concentrated leachate were over 98%. In addition, the results of free radical scavenging showed that hydroxyl radicals were dominant under alkaline conditions. The results of this study demonstrated that coupling heat and ultraviolet activated persulfate oxidation is a promising technique for the treatment of nanofiltration concentrated leachate.

Emergency response to the explosive growth of health care wastes during COVID-19 pandemic in Wuhan, China.

During the Coronavirus Disease 2019 (COVID-19) as a worldwide pandemic, the security management of health care wastes (HCWs) has attracted increasing concern due to their high risk. In this paper, the integrated management of HCWs in Wuhan, the first COVID-19-outbreaking city with over ten millions of people completely locking down, was collected, investigated and analyzed. During the pandemic, municipal solid wastes (MSWs) from designated hospitals, Fangcang shelter hospitals, isolation locations and residential areas (e.g. face masks) were collected and categorized as HCWs due to the high infectiousness and strong survivability of COVID-19, and accordingly the average production of HCWs per 1000 persons in Wuhan explosively increased from 3.64 kg/d to 27.32 kg/d. Segregation, collection, storage, transportation and disposal of HCWs in Wuhan were discussed and outlined. Stationary facilities, mobile facilities, co-processing facilities (Incineration plants for MSWs) and nonlocal disposal were consecutively utilized to improve the disposal capacity, from 50 tons/d to 280.1 tons/d. Results indicated that stationary and co-processing facilities were preferential for HCWs disposal, while mobile facilities and nonlocal disposal acted as supplementary approaches. Overall, the improved system of HCWs management could meet the challenge of the explosive growth of HCWs production during COVID-19 pandemic in Wuhan. Furthermore, these practices could provide a reference for other densely populated metropolises.

Molecular insights into the structure destabilization effects of ECG and EC on the Aß protofilament: An all-atom molecular dynamics simulation study.

The formation of Aß into amyloid fibrils was closely connected to AD, therefore, the Aß aggregates were the primary therapeutic targets against AD. Previous studies demonstrated that epicatechin-3-gallate (ECG), which possessed a gallate moiety, exhibited a greater ability to disrupt the preformed Aß amyloid fibrils than epicatechin (EC), indicating that the gallate moiety was crucial. In the present study, the molecular mechanisms were investigated. Our results demonstrated that ECG had more potent disruptive impacts on the ß-sheet structure and K28-A42 salt bridges than EC. We found that ECG significantly interfered the interactions between Peptide-4 and Peptide-5. However, EC could not. The disruption of K28-A42 salt bridges by ECG was mainly due to the interactions between ECG and the hydrophobic residues located at C-terminus. Interestingly, EC disrupted the K28-A42 salt bridges by the interactions with C-terminal hydrophobic residues and the cation-π interactions with K28. Moreover, our results indicated that hydrophobic interactions, H-bonds, π-π interactions and cation-π interactions between ECG and the bend of L-shaped region caused the disaggregation of interactions between Peptide-4 and Peptide-5. Significantly, gallate moiety in ECG had contributed tremendously to the disaggregation. We believed that our findings could be useful for designing prospective drug candidates targeting AD.