Effective degradation of tetracycline in aqueous solution by an electro-Fenton process using chemically modified carbon/α-FeOOH as catalyst.

This study applied an electro-Fenton process using chemically modified activated carbon derived from rubber seed shells loaded with α-FeOOH (RSCF) as catalyst to remove tetracycline residues from aquatic environment. Catalyst characteristics were evaluated using SEM, EDS, XRD, and XPS, showing successful insertion of iron onto the activated carbon. The effects of the parameters were investigated, and the highest treatment efficiency was achieved at pH of 3, Fe: H2O2 ratio (w/w) of 500:1, catalyst dose of 1 g/L, initial TCH concentration of 100 mg/L, and electric current of 150 mA, with more than 90% of TCH being eliminated within 30 min. Furthermore, even after five cycles of use, the treatment efficiency remains above 90%. The rate constant is calculated to be 0.218 min-1, with high regression coefficients (R 2 = 0.93). The activation energy (Ea) was found to be 32.2 kJ/mol, indicating that the degradation of TCH was a simple reaction with a low activation energy. These findings showed that the RSCF is a highly efficient and cost-effective catalyst for TCH degradation. Moreover, the use of e-Fenton process has the advantage of high efficiency, low cost thanks to the recyclability of the catalyst, and environmental friendliness thanks to less use of H2O2.

The global evolution of mental health problems during the COVID-19 pandemic: A systematic review and meta-analysis of longitudinal studies.

BACKGROUND: The COVID-19 pandemic impacted mental health, but the global evolution of mental health problems during the pandemic is unknown. We conducted a systematic review and meta-analysis of longitudinal studies to evaluate the global evolution of mental health problems during the pandemic. METHODS: To conduct this systematic review, we searched for published articles from APA PsycInfo (Ovid), CINAHL (EBSCOhost), Embase (Ovid), MEDLINE (Ovid), and Web of Science. Longitudinal (at least 2 waves during the COVID-19 pandemic) and peer-reviewed articles on mental health problems conducted as from 2020 and after were included in the current study. Of 394 eligible full texts, 64 articles were included in the analysis. We computed random effects, standardized mean differences, and log odds ratio (LOR) with 95 % CIs. The meta-analysis protocol was registered with PROSPERO (CRD42021273624). RESULTS: Results showed that anxiety (LOR = -0.33; 95 % CI, -0.54, -0.12) and depression symptoms (LOR = -0.12; 95 % CI, -0.21, -0.04) decreased from baseline to follow up. However, other mental health problems showed no change. Higher prevalence rates (40.9 %; 95 % CI, 16.1 %-65.8 %) of psychological distress were found in months after July 2020, respectively, while there were no significant month differences for the prevalence of other mental health problems. Higher means of anxiety (d = 3.63, 95 % CI, 1.66, 5.61), depression (d = 3.93; 95 % CI, 1.68, 6.17), and loneliness (d = 5.96; 95 % CI, 3.22, 8.70) were observed in May 2020. Higher prevalence of anxiety, depression, and PTSD and higher means of anxiety, depression and loneliness were observed in North America. The prevalence of psychological distress and insomnia was higher in Latin America and Europe, respectively. LIMITATIONS: There is a lack of longitudinal studies in some parts of the world, such as Africa, the Caribbean, India, the Middle East, in Latin America, and Asia. CONCLUSIONS: Results indicated that anxiety and depression symptoms decreased during the COVID-19 pandemic while other mental health problems showed no statistical change. The findings reveal that mental health problems peaked in April and May 2020. Prevalence of mental health problems remains high during the pandemic and mental health prevention, promotion and intervention programs should be implemented to mitigate the consequences of the COVID-19 pandemic on the global population.

PCDD/Fs and dl-PCBs concentrations in water samples of Taiwan.

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (dioxin-like PCBs) have received much public concern worldwide due to their persistence and toxicity. The presence of these compounds in environmental matrices, especially in water bodies, enhances the risk of human exposure to these toxic pollutants. In this study, seventeen 2,3,7,8 chlorinated PCDD/Fs and twelve dl-PCBs were measured in 11 groundwater samples collected throughout Taiwan and 2 surface water samples collected in northern Taiwan. PCDD/F and PCB concentrations in two surface water samples are relatively low, with the average concentrations of 0.038 and 0.001 pg WHO-TEQ/L (7.474 and 1.862 pg L-1), respectively. As for groundwater samples, PCDD/F concentrations measured range from 0.005 to 3.963 pg WHO-TEQ/L, while dl-PCB concentrations range from 2.5 × 10-5 to 0.189 pg WHO-TEQ/L. Total WHO-TEQ concentrations range from 0.005 to 3.963 pg WHO-TEQ/L, reflecting serious contamination of PCDD/Fs and PCBs in groundwater at some sampling sites. In term of total PCDD/Fs, PCDDs constitute a significant fraction (77.3%), and OCDD is most abundant, followed by HpCDD/Fs and HxCDD/Fs. PCB 118 is dominant among 12 dl-PCBs measured, followed by PCB 105 and PCB 77. Solid-phase PCDD/Fs generally predominate in water samples and PCDFs are of slightly lower distribution in solid phase in comparison with PCDDs, while PCBs are mainly distributed in dissolved phase. Results of principal component analysis (PCA) indicate that use of PCP and Na-PCP, thermal processes and PCBs-containing products might be the major sources of PCDD/Fs and PCBs in water samples measured.