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Abstract: The equilibrium structures, interaction energies, and bonding properties of ternary XHY[??]NCH[??]HM complexes are studied by ab initio calculations, where X = F, C1, Br, Y = S, Se, and [...]

Bisphenol A (BPA) and its derivatives have extensive applications as lubricants and polymer stabilizers and components of photographic developers. In this study, the photo catalytic degradation of bisphenol A (BPA) was studied on ZnO nanoparticles coated on a fixed bed which was treated in two light sources including ultraviolet-C (UVC-254 nm) and natural solar in compound parabolic concentrators (CPC). Characterization of the ZnO nanoparticles samples was performed by field-emission scanning electron microscope, X-ray diffraction, ultraviolet-visible (UV-VIS) spectrophotometer, and Brunauer–Emmett–Teller measurements. The highest photocatalytic and photolysis activity for the degradation of BPA has been obtained for the ZnO/UVC and UVC with 99% and 40% efficiencies in 120 min. Also, the highest photocatalytic and photolysis activity for the degradation of BPA has been obtained for the CPC reactor and 97% and 31% efficiency in 120 min. The photocatalytic degradation reaction of BPA was monitored by high-performance liquid chromatography, total organic carbon, and gas chromatography/mass (GC-MASS) analyses. The results of GC-MASS analysis show that the degradation of BPA occurs through the production of glycolic acid, benzoic acid, and vinyl phenol products and its decomposition occurs by ring fission and then subsequent reactions with OH radicals. These results show that the photo catalytic degradation of solar light and UV has high efficiency in BPA removal as well as effluent mineralization. [ABSTRACT FROM AUTHOR]

Background and Objectives: Coronavirus disease 2019 (COVID-19) is a pandemic caused by the novel virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Knowing the virus's behavior and its persistence in different environments are crucial and will lead to the proper management of the disease. In this study, air, surface, and sewage samples were taken from different parts of referral hospitals for COVID-19. Materials and Methods: Air samples were taken with impinger, surface samples with swabs, and sewage samples were taken from the hospital wastewater treatment plant. After viral genome extraction, a real-time RT-PCR test was applied to confirm the presence of SARS-CoV-2 RNA in the collected samples. Results: The virus genome could be traced in the wards and wastewater related to hospitalized COVID-19 patients. Overally, 29%, 16%, and 37.5% of air, surface, and sewage samples were positive for the SARS-CoV-2 genome, respectively. Conclusion: Findings of such studies provide valuable results regarding the degree of contamination of hospital environments and the risk of virus transmission in different environments and among hospital staff and patients. [ABSTRACT FROM AUTHOR]

Background: The major concern to meet environmental regulations is related with the decolorization and detoxification of industrial dyes contaminated wastewater. So, this study was undertaken to examine the use of bacteria isolated from wastewater of textile factories in the removal of the synthetic textile dyes (Sudan Black, Methyl Red, Malachite Green, Rhodamine B and Brilliant Cresyl Blue). Methods: Dye contaminated wastewater was collected from some synthetic textile factories in Gorgan and Gonbad, Iran, and evaluated for the screening and isolation of bacteria capable of decolorizing textile dyes. The effect of function of operational parameters includes temperature (25, 37 and 50 °C), pH (4, 6 and 8) and initial dye concentration (100, 200 and 300 mg/mL) on the efficiency and rate of discoloration was assessed. Results: Totally, out of the 19 bacterial isolates from textile wastewater: Five bacterial isolates showed dye discoloration ability and the most efficient bacterial isolates were Enterococcus faecium and Pantoea spp. that decolorized Methyl Red, Sudan Black and Malachite Green dyes at 25-37°C, concentration of 200-300 mg/mL and slightly acidic to neutral pH. Enterococcus bacterium was able to decolorize Sudan Black to the 19.79% in the concentration of 100 mg/ml and pH=8 and temperature of 50°C. The highest amount of decolorizing was observed by Pantoea on Malachite Green to the amount of 73%. Enterococcus had the highest decolorizing on Methyl Red to the 65.7%. The amount of decolorizing on Sudan Black by Enterococcus (49.9%) was also higher than Pantoea (39.7%). Conclusion: Isolated bacteria had a significant reduction in toxicity and cationic malachite green dye and azo dye- methyl red. Thus, bacteria can be used in full-scale industrial wastewater treatment with the bio-synergy and its application in discoloration. [ABSTRACT FROM AUTHOR]

p-nitroaniline (PNA) is a well-known acute oral, dermal, and inhalation toxin that has been reported as a priority toxic pollutant by the Environmental Protection Agency (EPA). In this study, MgAl-layered double hydroxides (MgAl-LDH) nanoparticles were prepared by a simple and fast co-precipitation method and used as a catalyst in the ozonation process to remove PNA from aqueous solutions. Next, the structure of the synthesized MgAl-LDH was investigated by X-ray diffraction pattern and field emission scanning electron microscopy-energy dispersive spectroscopy. The response surface methodology was used to investigate the effects of different parameters including reaction time, initial PNA concentration, pH, and LDH loading on the removal of PNA by MgAl-LDH catalytic ozonation process (MgAl-LDH COP). The highest removal efficiency of 91.5% was observed in optimum conditions as follows: initial PNA concentration of 162.5 mg/L, pH of 8.25, LDH loading of 750 mg/L, and reaction time of 70 min. The quadratic model was obtained with a high degree of fit. The removal values of COD and TOC were 77% and 68%, respectively. As a result, MgAl-LDH COP, as an excellent practical alternative, has a high performance in removing persistent compounds such as PNA from aqueous solutions. [ABSTRACT FROM AUTHOR]

Humic acid (HA) is a natural organic matter, which is naturally present in raw water sources due to the decomposition of dead animals and plants. Therefore, the catalytic properties of a carbonaceous nanocomposite in the catalytic ozonation process (COP) of HA were investigated, and the results were compared with those obtained from the single ozonation process (SOP). Magnetic carbonaceous nanocomposite, as a novel catalyst, was applied to optimize the conditions for the removal of HA in the COP, and the influential parameters such as pH, retention time, catalyst dosage, and addition of radical scavengers were all evaluated. This is an experimental study in which the removal of HA by a COP was investigated in a cylindrical glass reactor (a useful volume of 250 mL) with a semi-continuous flow. Catalyst raw material was the granular activated carbon (GAC) that has been stabilized on Fe3O4 nanoparticles by the calcination method. The results revealed that by increasing the retention time, pH, and catalyst dosage, HA and TOC removal efficiencies by both process (SOP and COP) was increased. The highest removal efficiencies of HA and TOC in the COP process were 95% and 87.67%, respectively while their removal efficiencies in the SOP process were 76.8% and 67.1% under the conditions including pH of 9, contact time of 60 min, and HA concentrations of 15 mg/L. The highest removal of the HA by the SOP and catalyst adsorption was obtained to be 76% and 5.8% after 60 min, respectively; however, it was observed to be 95.7% in the COP, in the same contact time. The presence of tert-butanol alcohol (TBA) did not significantly affect the removal of the HA in the COP. Practically, this study revealed that the magnetically activated carbon catalyst could be potentially employed in the COP for the treatment of the water having average concentrations of HA substances. [ABSTRACT FROM AUTHOR]

The olive oil extraction industry is one of the most polluting wastewaters from the food industry, which is considered an important economic activity in the world. The environmental effects of olive wastewater are related to chemical and organic loading, which is resistant to biodegradation processes. The purpose of this study was to determine the efficiency of combined electrocoagulation, catalytic ozonation, to reduce organic load and improve the biodegradability of olive oil sewage. The present study was experimental on a laboratory scale and was done at a batch reactor on actual olive wastewater. The electrocoagulation process was performed using Fe electrodes at a current density of 0.73, 0.5, 0.05/dm. The optimal conditions for the electrocoagulation process were obtained at a flow rate of 0.5/dm for 45 min reaction time, so that the removal efficiency of TOC, COD, and turbidity was 75, 80 and 94%, respectively. Then the treated wastewater under these optimal conditions entered the catalytic ozonation process (COP) reactor. In the COP process, the TOC and COD concentrations reached 105 and 210 mg/L after 90 min (44% and 56% removal). Eventually, the effluent was introduced into the biology*ical reactor and the removal efficiency of COD and TOC were investigated. So, the amount of TOC and COD decreased from 105 and 210 mg/L to 22.3 mg/L and 37 mg/L, respectively. As a result, the overall efficiency of the EC/COP/SBR system in removing COD and TOC was 98.4% and 97.2%, respectively. The combination of these processes is very effective in comparison with other processes for the treatment of olive sewage. [ABSTRACT FROM AUTHOR]

Ammonia in the form of ammonium ion is toxic and could decrease the dissolved oxygen in water and endanger the aquatic life. The aim of this study is the removal of ammonium using a new method of oxidation and adsorption by catalytic ozonation and clinoptilolite zeolite, respectively. The research method is an experimental study. First, optimal pH of ammonium adsorption on carbon catalyst (5 g/L), Garmsar and Firoozkooh zeolites and oxidation process were determined. Then, in catalytic ozonation process, the effect of other variables on ammonium removal efficiency such as the concentration of carbonic catalyst (0.5-50 g/L) and the reaction time were investigated. Then, the effect of retention time and adsorbent concentration on adsorption of the remaining ammonium and nitrate production by the oxidation process using zeolites and their modifications were determined. The results showed that optimum pH for the ammonium adsorption process by carbon catalyst, catalytic ozonation and zeolite were 8, 9 and 8, respectively. However, the optimum pH of 4 was determined for nitrate removal. The highest ammonium absorption capacity was related to natural Firoozookh zeolite as 18.5 mg/g, and the effect of ligand and acid modification decreased the absorbed capacity by 12% and 14%, respectively. The highest nitrate removal efficiency was related to Garmsar ligand modified zeolite (98%) and an absorption capacity of 11.2 mg/g. In the catalytic ozonation process/absorption process, the concentration of ammonium was decreased to 0.6 mg/L. This method effectively eliminates ammonium, and the modification of zeolite with cationic surfactant increased the efficiency of nitrate removal and therefore the concentrations of all pollutants were below standards. [ABSTRACT FROM AUTHOR]

Non-degradation compounds are nowadays not being disposed into the environment, or are removed before being disposed into the environment. The aim of this study was to assess the degradation of aniline from aqueous media by electro/Fe2+/peroxydisulphate (PDS) process. The effects of different parameters like pH (3-9), electric current (EC; 10-30 mA/cm2), dose of PDS (10-40 mM), Fe2+ dose (5-20 mM) and initial aniline concentration (20-100 mg/L) on the degradation of aniline were investigated in the laboratory reactor in the batch condition. The results showed that the removal efficiency of aniline decreased by increasing the initial pH and pollutant concentration; however, with increasing EC and PDS doses and ferrous concentration, the removal efficiency increased. The maximum of aniline degradation, equalling 83%, was obtained at 60 min of reaction time. Also, for reaction time of 60-min runs, PDS only, EC only, PDS + Fe, PDS + EC and PDS + Fe + Fe, respectively, have 8.9%, 53%, 43%, 65% and 83% of the removal efficiency. The degradation efficiency of aniline from synthetic wastewater was significantly improved when the combined processes PDS/electro-conduction/Fe2+ was applied. [ABSTRACT FROM AUTHOR]

A new strategy in catalytic ozonation removal method for degradation and detoxification of phenol from industrial wastewater was investigated. Magnetic carbon nanocomposite, as a novel catalyst, was synthesized and then used in the catalytic ozonation process (COP) and the effects of operational conditions such as initial pH, reaction time, and initial concentration of phenol on the degradation efficiency and the toxicity assay have been investigated. The results showed that the highest catalytic potential was achieved at optimal neutral pH and the removal efficiency of phenol and COD is 98.5% and 69.8%, respectively. First-order modeling demonstrated that the reactions were dependent on the initial concentration of phenol, with kinetic constants varying from 0.038 min-1 ([phenol] o = 1500 mg/L) to 1.273 min-1 ([phenol]o = 50mg/L). Bioassay analysis showed that phenol was highly toxic to Daphnia magna (LC500 96 h = 5.6 mg/L). Comparison of toxicity units (TU) of row wastewater (36.01) and the treated effluent showed that TU value, after slightly increasing in the first steps of ozonation for construction of more toxic intermediates, severely reduced at the end of reaction (2.23). Thus, COP was able to effectively remove the toxicity of intermediates which were formed during the chemical oxidation of phenolic wastewaters. [ABSTRACT FROM AUTHOR]