Synergetic Photocatalytic Peroxymonosulfate Oxidation of Benzotriazole by Copper Ferrite Spinel: Factors and Mechanism Analysis.

The development of oxidation processes with the efficient generation of powerful radicals is the most interesting and thought-provoking dimension of peroxymonosulfate (PMS) activation. This study reports the successful preparation of a magnetic spinel of CuFe2O4 using a facile, non-toxic, and cost-efficient co-precipitation method. The prepared material exhibited a synergetic effect with photocatalytic PMS oxidation, which was effective in degrading the recalcitrant benzotriazole (BTA). Moreover, central composite design (CCD) analysis confirmed that the highest BTA degradation rate reached 81.4% after 70 min of irradiation time under the optimum operating conditions of CuFe2O4 = 0.4 g L-1, PMS = 2 mM, and BTA = 20 mg L-1. Furthermore, the active species capture experiments conducted in this study revealed the influence of various species, including •OH, SO4•-, O2•-, and h+ in the CuFe2O4/UV/PMS system. The results showed that SO4•- played a predominant role in BTA photodegradation. The combination of photocatalysis and PMS activation enhanced the consumption of metal ions in the redox cycle reactions, thus minimizing metal ion leaching. Additionally, this maintained the reusability of the catalyst with reasonable mineralization efficiency, which reached more than 40% total organic carbon removal after four batch experiments. The presence of common inorganic anions was found to have a retardant effect on BTA oxidation, with the order of retardation following: HCO3- > Cl- > NO3- > SO42-. Overall, this work demonstrated a simple and environmentally benign strategy to exploit the synergy between the photocatalytic activity of CuFe2O4 and PMS activation for the treatment of wastewater contaminated with widely used industrial chemicals such as BTA.

Air Surveillance for Viral Contamination with SARS-CoV-2 RNA at a Healthcare Facility.

The transmission pathway of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 also called COVID-19 disease) in indoor environments are the main area of contention between health systems and scientists. In this context, little has been investigated about the collection of airborne viral shedding. Here, we collected air samples from 24 locations inside the sole COVID-19 patient care center in Zabol, Iran, for screening SARS-CoV-2 RNA from March to May 2021. Locations included the ICU, COVID-19 wards (CWs) rooms, corridors, nearby nurses' stations, and toilets. We identified the SARS-CoV-2 RNA in breathing zone of CW, in room air, with the positivity rate of 2.5% at a concentration of 17 × 103 virus genome copies/m3 air. It also investigates the relationship between local climate conditions [i.e., temperature and relative humidity] and COVID-19 transmission with the evolution of daily official data on the number of new cases, hospitalizations, and deaths. Current data explained that the difference of temperature and humidity may affect the behavior of virus along with other factors, i.e., population density, individual viral shedding, and infectious dose of SARS-CoV-2 (both indoor and outdoor). Our data support the potential SARS-CoV-2 airborne transmission indoors suggesting the specific safety assessment of building to improve ventilation solutions besides proper using face masks and extensive public health interventions.

Data on photo-catalytic degradation of 4- chlorophenol from aqueous solution using UV/ZnO/persulfate.

The presence of chlorinated aromatic pollutants like 4- chlorophenol (4CP), even at low concentrations, in the wastewater should be controlled urgently, because of their high toxicity, carcinogenic potential and poor biodegradability. This dataset reveals the effectiveness of an advanced oxidation process (AOP) for attenuating of 4 CP. The AOP of UV/ZnO/persulfate and the influence of various parameters like pH, persulfate dosage and ZnO dosage were studied and the optimum removal conditions could be easily implied by readerships. The efficiency of > 90% was attained for degrading of 4CP by UV/ZnO/persulfate system at the experimental conditions of pH of 7, persulfate dosage of 11 mg/L, 4CP concentration of 10 mg/L, and ZnO dosage of 1 g/L. The data had a good agreement with pseudo first-order kinetic model. Thus, the UV/ZnO/persulfate system is an efficient method for decreasing 4CP from aqueous solution.

Photocatalytic activation of peroxymonosulfate by TiO2 anchored on cupper ferrite (TiO2@CuFe2O4) into 2,4-D degradation: Process feasibility, mechanism and pathway.

A thorough study of photo-oxidation efficiency of TiO2@CuFe2O4 dissociating peroxymonosulfate (PMS) is reported in detail. The origin of high catalytic activity was discussed as evidence by numerous controlled trials and several operational parameters. Based on quenching tests, possible mechanism and pathway of degradation were proposed. 2,4-dichlorophenoxyacetic acid (2,4-D) degradation in TiO2@CuFe2O4/UV/PMS system could abide pseudo-first-order kinetics. Moreover, reaction rate constant (Kobs) showed a linear increasing trend as PMS and catalyst concentrations increased. Over 97.2% of 2,4-D (20 mg/L) was degraded within 60 min at 0.3 mM PMS and 0.1 g/L TiO2@CuFe2O4. However, the water matrix species inhibited 2,4-D degradation to different amounts and the inhibiting effect was as follows: HCO3- > NO3-  > Cl- > SO42-. As-prepared catalyst showed a high ability of PMS activation, compared to other studied oxidants. Particularly, sulfate radicals were accounted for 2,4-D degradation in the catalytic oxidation reaction. TiO2@CuFe2O4 catalyst displayed the excellent recyclability and durability. Identification of intermediates and end-products brought about the conclusion that enhanced degradation involving dechlorination, dehydrogenation, hydroxylation, and ring cleavage, through SO4-, OH, O2- and holes attack during TiO2@CuFe2O4/PMS photocatalysis of 2,4-D. As conclusion, integration of TiO2, CuFe2O4 and UV light to efficient activation of PMS can be proposed as a successful and promising method to wastewater treatment effectively, because of the cogeneration of different reactive oxidizing species, simple and easy recovery of catalyst and good catalytic activity.

Phenanthrene removal from liquid medium with emphasis on production of biosurfactant.

In the current study, there are some considerable issues which focused on: (1) the production of biosurfactant, (2) its correlation with the initial bacterial inoculum in the liquid phase and (3) its effect on polycyclic hydrocarbon (PAH) bioremediation performance. Therefore, two strains Pseudomonas facilis and Pseudomonas spp. were able to form a large clear zone diameter on the oil surface. Phenanthrene (PHE) was also utilized as a sole substrate. Furthermore, biosurfactant production (BP) was detected by methylene blue analysis procedure and surface tension (ST) lowering. The capacity of these two strains to lower the aqueous ST was 29 and 30.7 from 72 mN m-1 by 6 days for P. facilis and Pseudomonas spp., respectively. Higher initial bacterial inoculation led to an improvement in PHE removal (P < 0.0001). But there was no significant correlation between either PHE solubility or BP and the initial bacterial inoculation. The removal efficiency of 88.44% within 21 days confirms that the inoculation of P. facilis led to the considerable BP for removal of PAHs from contaminated water.

Biosurfactant production and its effects on solubilization activity of phenanthrene: a longitudinal study.

Pseudomonas facilis and Pseudomonasspp., isolated on the basis of its ability to grow on polycyclic aromatic hydrocarbon, was assayed for biosurfactant production (BP) potentials by measuring the surface tension (ST) of the culture supernatant at different time intervals. The strains in three levels of initial inoculum size (OD600 nm = 0.5, 1, 1.5) were added to medium to determine if bacterial inoculum size affects solubilization of phenanthrene (PHE).The result showed that although the two strains reduced the mean ST to less than 34.12 mN m(-1) at the end of day 6, mean solubilization activity of PHE reached 77.05 mg L(-1) on the sixth day. There was a significant increase in BP over time (P = 0.008); reaching its peak, 157.84 mg L(-1), at the end of the sixth day. Mean solubilization activity of PHE was not significantly different for the two strains (P = 0.216). The time-course study revealed that the ST reduction and BP potential was enhanced as inoculation size increased, leading to higher PHE solubility during the incubation time. However, the trend of increase in PHE solubility was not totally in the same way to cell growth and BP. It may be suggested that more bacterial density needs to be inoculated for practical application of effective bioremediation.