Enhancement of the catalytic performance of Co-ZIF/WO3 heterostructures for selective catalytic reduction of NOx.

Nitrogen oxides (NOx) are one of the growing air pollutants in industrial countries, and their emissions are regulated by stringent legislation. Therefore, the design of the catalyst comprised of metal oxides and ZIFs a potential solution for improving selective catalytic reduction (SCR) of NOx. Here, an efficient strategy was described to fabricate Co-ZIF/WO3 heterostructures for SCR of NOx. First, WO3 nanostructures were fabricated by the solvothermal method, and subsequently epitaxial growth of ZIF-67 on the metal oxide surface to create a new type of semiconductor Co-ZIF/WO3 heterostructures. The obtained heterostructures were systemically characterized by wide-angle XRD, FESEM, UV DRS, FT-IR, AFM, and TEM spectroscopies. The Co-ZIF/WO3 heterostructures shift the temperature corresponding to the maximum conversion around 50 °C towards lower temperatures. The maximum conversion is substantially enhanced from 55% at 400 °C to 78% at 350 °C. The enhanced activity is attributed to better interaction and synergic effect of WO3 incorporated into ZIF-67 and also the electron transfer facility between the WO3 and Co species in Co-ZIF/WO3 heterostructures. Moreover, Co-ZIF/WO3 results in a distinct effect on the production of carbon monoxide (CO) in the product gas stream. The current study highlights some of the challenges in the development of semiconductor-based heterostructures for a decrease in air pollution.

Photocatalytic oxidation of ciprofloxacin by UV/ α-Fe2O3/sulfite: mechanism, kinetic, degradation pathway.

This study was aimed to investigate the synergistic effect of sulfite reducing agent on the UV/hematite (α-Fe2O3) photocatalytic process performance in the removal of ciprofloxacin from the aqueous solutions. For this purpose, influence of the operation parameters including initial antibiotic concentration, pH, sulfite to hematite molar ratio and the reaction time on the UV/hematite/sulfite (UHS) performance was evaluated. UV alone, UV/hematite (α-Fe2O3) (UH) and UV/sulfite (US) processes indicated to have little influence on the ciprofloxacin degradation. The simultaneous presence of hematite and sulfite in the reaction environment was significantly improved the degradation efficiency, as UHS process indicated an increase of 89%, 64% and 59% in the removal performance than that of UV alone, UH and US processes, respectively. Under the selected condition (pH of 7.0 and sulfite/hematite molar ratio of 1:3), 94% of ciprofloxacin (CFX) was degraded after 5 min of reaction. In addition, robs (mg L-1 min) value for UHS process was 25.26, 6 and 4.8 times that of UV alone, UH and US processes, respectively. The EEO and TCS values for UV alone, US, UH and UHS processes were (44.21 kWh/m-3 and 2.08 $ m-3), (10.5 kWh/m-3 and 1.1 $ m-3), (4.8 kWh/m-3 and 1.04 $ m-3) and (1.75 kWh/m-3 and 0.85 $ m-3), respectively. In addition, the study of the reaction mechanism showed hydroxyl and sulfate radicals play a vital role in the degradation of CFX by UHS process.

Dual immobilization of magnetite nanoparticles and biosilica within alginate matrix for the adsorption of Cd(II) from aquatic phase.

The adsorption of cadmium ions by magnetite (Fe3O4)@biosilica/alginate (MBA nano-hybrid) was the main aim of the present investigation. Herein, MBA nano-hybrid was synthesized via chemical precipitation technique. As-synthesized MBA nano-hybrid was characterized using FT-IR, FESEM and XRD analyzes. Based on the results, the maximum adsorption capacity of the adsorbent for the removal of Cd(II) was obtained at the initial pH of 7.0. At the initial Cd(II) concentration of 40 mg/L, increasing the reaction time to 180 min led to the Cd adsorption of 35.36 mg/g. Since the removal of Cd(II) after the reaction time of 60 min was insignificant, the reaction time of 60 min was considered as optimum reaction time for performing the experimental runs. According to the results, Langmuir isotherm and pseudo-second order kinetic models were the best fitted models with high correlation coefficients (R2 > 0.99). The results of thermodynamic study indicated exothermic (positive ΔH°) and spontaneous nature (negative ΔG°) of the adsorption of Cd(II) on the surface of MBA nano-hybrid. Negligible reduction in the adsorption capacity of the nano-hybrid was observed (16.57%) after fifth experimental runs, indicating high reusability potential of the as-synthesized nano-hybrid adsorbent.

Monitoring and eco-toxicity effect of paraben-based pollutants in sediments/seawater, north of the Persian Gulf.

The current work is documented as the first record of the characteristics, removal efficiency, partitioning behavior, fate, and eco-toxicological effects of paraben congeners in a municipal wastewater treatment plant (WWTP, stabilization ponds) and hospital WWTPs (septic tank and activated sludge), as well as seawater-sediments collected from runoff estuarine stations (RES) and coastal stations (CS) of the north of the Persian Gulf. The median values of Σparabens at the raw wastewater and effluent of the studied WWTPs were 1884 ng/L and 468 ng/L, respectively. The activated sludge system had a greater removal efficiency (56.10%) in removing ∑parabens than the septic tank (45.05%) and stabilization pond (35.54%). The discharge rates of methyl paraben (MeP) was computed to be 2.23, 21.18, and 9.12 g/d/1000 people for stabilization ponds, septic tank, and activated sludge, respectively. Median concentrations of Σparabens in seawater (103.42 ng/L) and sediments (322.05 ng/g dw) from RES stations were significantly larger than from CS stations (61.2 and 262.0 ng/g dw in seawater and sediments, respectively) (P < 0.05). The median of field-based koc for Σparabens was 130.81 cm3/g in RES stations and 189.51 cm3/g in CS stations. It was observed that the concentration of parabens could have negative impacts on some living aquatic populations (invertebrates and bacteria), but the risk was not significant for fishes and algae.

Antibacterial effect of TiO2 modified with poly-amidoamine dendrimer - G3 on S. aureus and E. coli in aqueous solutions.

This study investigated bacterial removal using TiO2 nanoparticles (NPs) modified with poly-amidoamine dendrimer macromolecule (PAMAM, G3). The PAMAM G3/TiO2 (nanohybrid) was used to specify antibacterial properties via broth microdilution (MBC-Minimum Bactericidal Concentration and MIC-Minimum Inhibitory Concentration-determination), paper disc diffusion, and surface plate count methods. The nanohybrid was characterized via the different techniques. The effects of different factors including initial bacteria count, run time, solution pH, and the nanohybrid concentration were studied. The nanohybrid cytotoxicity was studied on AGS and MKN45 cells line by MTT assay. It was revealed that the nanohybrid was effective in intercepting both bacterial strains growth. The MIC value for S. aureus and E. coli were determined to be 4 and 2 µg/mL, respectively. The MBC value for both strains were calculated to be 32 µg/mL. The results showed removal efficiency of 100% for S. aureus and E. coli bacteria in optimum situation. The decrease in cell viability in the dosage of 32 µg/mL after 72 h treatment for AGS and MKN45 cells line were shown to be 6.2 and 4.6%, respectively. The nanohybrid was able to decrease the S. aureus and E. coli count in solution, which meets the drinking water criterions aligned with WHO guidelines.

Degradation of ciprofloxacin using hematite/MOF nanocomposite as a heterogeneous Fenton-like catalyst: A comparison of composite and core-shell structures.

A novel strategy was described to fabricate hematite-MOF materials with morphologies (core-shell) and (composite) as an efficient peroxymonosulfate (PMS) activator for degrading ciprofloxacin (CIP) antibiotics. First, α-Fe2O3 nanoparticles (NPs) with a size distribution range of 80 nm were prepared by surfactant-assisted reflux method. Then, cobalt-based metal-organic framework (ZIF-67) was grown onto the α-Fe2O3 NPs with ultrasonic and solvothermal method, which can control the nanostructures morphology. The physicochemical properties of these nanostructures were probed by ATR-IR, WA-XRD, FESEM, VSM, TEM, and EDS spectroscopy. The results showed that all the added CIP (20 ppm) antibiotics were completely degraded in 30 min in the α-Fe2O3/ZIF-67 (0.10 g/L) and PMS (0.20 g/L) system with rate constant of 0.130 min-1. To validate the merits of the α-Fe2O3/ZIF-67, α-Fe2O3@ZIF-67 core-shell nanostructures were also applied under similar conditions. The findings demonstrated that Co/Fe species within α-Fe2O3/ZIF-67 composite catalyzed PMS synergistically to the formation of the OH and SO4- and 1O2 for CIP degradation. Furthermore, α-Fe2O3/ZIF-67 showed good recyclability enabling facile separation of the catalyst from reaction mixtures using an external magnet. The current protocol can be a useful criterion in designing various Magnetic-MOF composites with controlled morphologies for environmental remediation.

Application of the Fe3O4-chitosan nano-adsorbent for the adsorption of metronidazole from wastewater: Optimization, kinetic, thermodynamic and equilibrium studies.

The development of adsorbents with high adsorption performance is an effective method of removing metronidazole (MTZ). Therefore, Fe3O4-chitosan nano-adsorbent (CTS-MNPs) was synthesized. The SEM, TEM, FTIR, VSM and BET analyzes were applied to determine the surface morphologies, shape and size, functional groups, magnetic properties, size and volume of CTS-MNPs, respectively. R software using response surface methodology was applied to investigate the composition effect of input factors and output response. The second-order model because of insignificant lack of fit, lower P-value and also higher R2 indicated highly significant for adsorption of MTZ by CTS-MNPs. The predicted optimal conditions with considering the maximum removal efficiency (100%) were calculated for second-order model and were included (pH, 3; CTS-MNPs dosage, 2 g L-1; contact time, 90 min and MTZ concentration, 10 mg L-1). It is found that the experimental findings for the response are in good agreement with model predictions. The results declare MTZ adsorption onto CTS-MNPs involves a multilayer process (Freundlich isotherm model). Also, pseudo-second-order model indicated more appropriate for describing the MTZ adsorption onto the CTS-MNPs. The adsorption thermodynamic revealed an endothermic and spontaneous reaction for the adsorption of MTZ by CTS-MNPs.

Microbial contamination of keyboards and electronic equipment of ICU (Intensive Care Units) in Kashan University of medical sciences and health service hospitals.

Microbial contamination of computer keyboards and inanimate surfaces of electronic equipment in ICU (Intensive Care Units) can have a significant role for ICU-acquired colonization and a spectrum of nosocomial infections. The aim of this study was to survey the incidence of bacterial contamination and the distribution of species of computer keyboards and inanimate surfaces of bed side equipment in ICUs in Kashan University of medical sciences and health service hospitals. This descriptive, cross-sectional study was done on 75 computer keyboards and inanimate surfaces electronic equipment in 5 ICUs during 2016-2017. Samples were collected from computer keyboards and electronic equipment with normal saline rinsed swabs. Samples were Cultivated on Blood Agar (BA), and MacConkey Agar (MAC) and growing bacteria were identified based on their morphology and biochemical properties. Seventy six (76%) out of 75 computer Keyboards and electronic equipment were contaminated with bacteria and fungi. The most contamination pertained to gram positive bacteria (70.7%) and the most isolated bacteria were coagulase-negative staphylococci. The highest contamination rates were found on computer keyboards and electronic equipment of which were nurses. •This study demonstrates that monitoring inanimate surfaces and considering these surfaces as source of nosocomial infections is necessary.•In total, Seventy six (76%) out of 75 computer keyboards and electronic equipment in ICUs had positive culture.•It can be concluded that it is necessary for ICUs of Kashan university of medical sciences and Health service hospitals to have practical and regular program to reduce nosocomial infections.

Community health assessment: Knowledge, attitude and practice of women regarding water-pipe smoking in Bandar Abbas.

Based on the results of seventh round of community health assessment (CHA) in suburban areas of Bandar Abbas, "water-pipe smoking in women" was one of the major concerns of community members. Therefore, the present study designed to assess the knowledge, attitude and practice of women towards water-pipe smoking and related factors. High consumption of water-pipe among women was ranked as a prioritized health problem. To diagnose the problem, for creating action plan, the present cross - sectional study was conducted on 205 women aged over 18 randomly selected from Green-Tree region in suburb of Bandar Abbas city. All statistical analyses were performed using SPSS 24 software with 5% as the significant level. 205 women with a mean age of 36.9 (standard deviation:12.86) years, and a water-pipe prevalence of 15.1% were analyzed. The significant predictors of knowledge were educational level (ß = 0.182, p-value = 0.037), and being water-pipe smoker (ß = -0.251, p-value < 0.001); while for attitude they were educational level (ß = 0.221, p-value = 0.002), family size(ß = 0.152, p-value = 0.023), and subjective social status(ß = 0.149; p-value = 0.035); and for practice they was smoking waterpipe in parents (ß = -0.276, p-value < 0.001).The development action plans based on "CHA" could improve public health and enhance the performance of the community through improved education, policies and health interventions.