Abiotic natural attenuation of 1,2,3-trichloropropane by natural magnetite under O2 perturbation.

1,2,3-Trichloropropane (TCP) is an emerging groundwater pollutant, but there is a lack of reported studies on the abiotic natural attenuation of TCP by iron minerals. Furthermore, perturbation by O2 is common in the shallow subsurface by both natural and artificial processes. In this study, natural magnetite was selected as the reactive iron mineral to investigate its role in the degradation of TCP under O2 perturbation. The results indicated that the mineral structural Fe(II) on magnetite reacted with dissolved oxygen to generate O2-· and HO·. Both O2-· and HO· contributed to TCP degradation, with O2-· playing a more important role. After 56 days of reaction, 66.7% of TCP was completely dechlorinated. This study revealed that higher magnetite concentrations, smaller magnetite particle sizes, and lower initial TCP concentrations favored TCP degradation. The presence of <10 mg/L natural organic matter (NOM) did not affect TCP degradation. These findings significantly advance our understanding of the abiotic natural attenuation mechanisms facilitated by iron minerals under O2 perturbation, providing crucial insights for the study of natural attenuation.

For the Good of the People: an interpretive analysis of Chinese volunteerism in the critical matter of care at the start of the pandemic.

PURPOSE: China employed a unique volunteerism system where health care providers outside of Hubei Province, the epicentre, travelled to reverse the devastation wrought by coronavirus disease 2019 (COVID-19) at its global onset. The aim is to study the unique circumstances of Chinese volunteerism in the context of continuing pandemic threats, specifically exploring the experiences of 20 Chinese nurse and physician volunteers fighting COVID-19 during the outbreak. METHODS: Interviews were done through video calling. RESULTS: Using content analysis with a hermeneutic perspective, emerging patterns showed the ways in which China's particular manifestation of volunteerism teaches us how to engage global threats of this nature. The overarching lesson, For the Good of the People, was manifested in several dynamic and overlapping themes: 1) Reaching for Professional Standards Even in Crisis; 2) Constantly Caring Through Failures and Successes; and 3) Holding Fast to the Common Good. The devastation was met by the resilience of volunteers, who overcame profound challenges managing patient care. CONCLUSIONS: Volunteerism required sacrifice and tremendous support in the form of training and administrative direction, family support, and peer collaboration. Volunteers' physical and psychosocial wellbeing was a priority. Recognizing the representative themes can help societies plan for continuing and future events.

Degradation of 1,2,3-trichloropropane by unactivated persulfate and the implications for groundwater remediation.

Persulfate (PS) is widely used as an in situ chemical oxidation (ISCO) technology for groundwater and soil remediation. While conventional theory generally assumes that PS needs to be "activated" to produce reactive radicals for pollutant degradation, herein, PS without explicit activation system was discovered for the degradation of 1,2,3-TCP with the generation of reactive oxidation species (ROS). Comparison of five common ISCO oxidants (PS, peroxymonosulfate, hydrogen peroxide, potassium permanganate, and sodium percarbonate) indicated that only unactivated PS was able to degrade 1,2,3-TCP in both pure water and 12 natural water samples. 50 µM 1,2,3-TCP degradation can be continued as long as there is enough PS (50 mM). The degradation rate of 1,2,3-TCP increased 450 % when the PS concentration increased from 10 mM to 50 mM and 500 % when the temperature increased from 25 °C to 45 °C. Electron paramagnetic resonance (EPR) analyzes, hydroxyl radicals (·OH) probe reaction and radical quenching experiments confirmed the involvement of both sulfate radicals (SO4·-) and ·OH that were responsible for 1,2,3-TCP degradation and ·OH played a more important role. HCO3-, Cl- and NOM are three groundwater matrix species that are most likely to inhibit PS oxidation of 1,2,3-TCP. Compared to activated PS, unactivated PS is more promising and more practical for groundwater remediation, since it has several advantages: (1) longer lifetime and better long-term availability; (2) ability of enduring contaminant degradation; (3) applicable for low-permeability zones remediation and potential to alleviate contaminant rebound or tailing problems; (4) environmental friendly; and (5) lower cost. Overall, results of this study show that unactivated PS is a promising in situ remediation technology that may be a good candidate for the most challenging low permeable zone remediation.

Degradation of benzothiazole pollutant by sulfate radical-based advanced oxidation process.

Benzothiazole (BTH) is an aromatic heterocyclic compound with wide industrial applications. In view of its toxicity and wide environmental presence, previous efforts have been made to decompose BTH via different degradation pathways. However, due to its recalcitrant nature, conventional biological treatment methods cannot completely degrade BTH in the wastewater. In this study, sulfate radical-based advanced oxidation process (AOP) technique has been adopted to degrade BTH in aqueous phase. Persulfate (PS) was employed as radical promotor to generate sulfate radical via heat activation. Degradation of BTH by thermally activated persulfate via AOP has been experimentally evaluated in a systematic manner. Laboratory efforts have been made to examine the impact of a number of physiochemical parameters including the type of oxidants, reaction temperature, initial concentrations of PS and BTH, solution pH, and the presence of anionic species. It shows that a higher BTH degradation rate can be achieved by lowering BTH initial concentration or increasing PS concentration. Increasing solution pH or the presence of 10 mM of Cl-, Br-, CO32-, or HCO3- species can decrease BTH degradation rate. Furthermore, the primary radical(s) responsible for BTH degradation have been identified as sulfate radical at an acidic aqueous condition, and hydroxyl radical and sulfate radical combined at a basic condition. This study provides the necessary theoretical and technical foundations for BTH degradation via sulfate radical-based AOP technique. The conclusions from this study can substantially promote the field application of AOP, especially sulfate radical-based AOP technique, for BTH degradation in wastewater treatment process.