Degradation of Acid Red 18 in an aqueous environment by TiO2/Zeolite nano photocatalyst

In this study, the TiO2 nanoparticles were supported on Y-type zeolite as a new photocatalyst and used to degrade Acid Red 18 in aqueous media. The nano photocatalyst was synthesized by coprecipitation procedure and characterized by Fourier transfer infrared (FTIR), field emission scanning electron microscopy (FE-SEM), and X-ray powder diffraction (XRD). The central composite design (CCD) was employed for experimental design. The effect of operative variables including contact time, photocatalyst dosage and pH were investigated. The ANOVA (analysis of variance) studies displays the second-order regression model and a high determination coefficient value (R2 = 0.9953, R2pred = 0.9642, R2adj = 0.9910) for the destruction of AR18 was obtained. The contour plots were applied to study the shares of each variable and their interactions on the degradation of AR18. The optimal circumstances predicted by the model were as the following: the catalyst concentration at 0.88g/L, pH at 6.5, and contact time in 125 min. In this situation, the predicted and actual dye removal were 98.5% and 96.3%, respectively. The removal of COD (chemical oxygen demand) after 125 min was 53% indicating, the notable performance of photocatalyst in mineralization of AR18

Global impact of COVID-19 on stroke care and IV thrombolysis

Objective To measure the global impact of COVID-19 pandemic on volumes of IV thrombolysis (IVT), IVT transfers, and stroke hospitalizations over 4 months at the height of the pandemic (March 1 to June 30, 2020) compared with 2 control 4-month periods. Methods We conducted a cross-sectional, observational, retrospective study across 6 continents, 70 countries, and 457 stroke centers. Diagnoses were identified by their ICD-10 codes or classifications in stroke databases. Results There were 91,373 stroke admissions in the 4 months immediately before compared to 80,894 admissions during the pandemic months, representing an 11.5% (95% confidence interval [CI] -11.7 to -11.3, p < 0.0001) decline. There were 13,334 IVT therapies in the 4 months preceding compared to 11,570 procedures during the pandemic, representing a 13.2% (95% CI -13.8 to -12.7, p < 0.0001) drop. Interfacility IVT transfers decreased from 1,337 to 1,178, or an 11.9% decrease (95% CI -13.7 to -10.3, p = 0.001). Recovery of stroke hospitalization volume (9.5%, 95% CI 9.2-9.8, p < 0.0001) was noted over the 2 later (May, June) vs the 2 earlier (March, April) pandemic months. There was a 1.48% stroke rate across 119,967 COVID-19 hospitalizations. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was noted in 3.3% (1,722/52,026) of all stroke admissions. Conclusions The COVID-19 pandemic was associated with a global decline in the volume of stroke hospitalizations, IVT, and interfacility IVT transfers. Primary stroke centers and centers with higher COVID-19 inpatient volumes experienced steeper declines. Recovery of stroke hospitalization was noted in the later pandemic months.Paroxysmal Cerebral Disorder

Degradation of Terphetalic Acid from Petrochemical Wastewater by Ozonation and O3/ZnO Processes in Semi Batch Reactor

Background & Aims of the Study: One of the toxic pollutants in the wastewater of petrochemical industries is Terphetalic acid. In this study, the degradation and mineralization of Terphetalic acid in aqueous environment were studied by Ozonation and O3/ZnO processes in a semi batch reactor. Materials & Methods: This study is an experimental research on a laboratory scale. The study executed on synthetic wastewater having Terphetalic acid. The impact of operational factors such as pH, initial concentration of ZnO and Terphetalic acid was also studied. Results: Different amounts of variables were optimized for the removal of Terphetalic acid in O3/ZnO process. The optimum conditions were achieved as follows: the [ZnO]=1.20 g/l, pH at 9, and [TPA]=70 mg/l. Conclusions: The results exhibited that at the predicted optimum conditions and after 30 min of reaction, the removal of Terphetalic acid and Total Organic Carbon (TOC) was 96.9 and 44.3%, respectively. The O3/ZnO process was powerful in the removal of TPA, but it can remove the TOC to some extent. &nbsp

An Investigation of p-Nitro Cresol Removal from Aqueous Environment by Fenton Process in a Batch Reactor

Background & Aims of the Study: One of the most carcinogenic and toxic pollutants is p-Nitro Cresol. In this study, the degradation and mineralization of p-Nitro Cresol in aqueous solution were investigated by Fenton process in a batch reactor. Materials & Methods: This study is an experimental research on a laboratory scale. The study executed on synthetic wastewater having p-Nitro Cresol. The impact of operational factors such as pH, initial concentration of hydrogen peroxide and Ferrous ions was also investigated. The Box&ndash;Behnken design (BBD) of experiments and the response surface methodology (RSM) were employed to study the effects of three independent variables in the response function to acquire the optimal conditions. Results:The ANOVA (analysis of variance) tests were executed to conclude the importance of the effects of independent variables on the response function. The ANOVA displayed a high determination coefficient value (R2=92.88, R2adj=96.85 and R2pred=82.06) and satisfactory prediction second-order regression model. Different amounts of variables were optimized for the removal of p-Nitro Cresol in Fenton process. The optimum conditions predicted by the model were as follows: the (Fe2+)=0.77 mM, pH at 2.95, and (H2O2)=19.8 mM. Conclusions: The results exhibited that at the predicted optimum conditions and after 45 min of reaction, the removal of p-Nitro Cresol and Chemical oxygen demand (COD) were 97.4 and 48.0%, respectively. The Fenton process was powerful in the removal of p-Nitro Cresol, but it can remove the COD to some extent

Application of Sonocatalyst and Sonophotocatalyst for Degradation of Acid Red 14 in Aqueous Environment

Background & Aims of the Study: Azo dyes are employed in industrial processes such as textile industry to create large quantities of colored sewages that have organic and non-organic materials. So, remediation of them is essential. In this project, degradation and mineralization of Acid red 14 (AR14) that is a mono Azo dye and widely used in the textile industries was investigated by Sonocatalysis and Sono photo catalyst in the presence of homogeneous (Fe3+) photo catalyst. Materials & Methods: This study is an experimental investigation on a laboratory scale. The study performed on synthetic wastewater that hold Acid red 14.The influence of operational parameters such as initial dye concentration and ultrasonic power on the sonochemical degradation was also studied. The optimization of variables was done by one factor at a time method. Results: The efficiency of the Sonophotocatalytic process with Fe3+ was higher than Sonocatalysis and photo catalyst processes alone. The combination of sonolysis, Fe3+ and&nbsp; photo catalyst caused a highly synergistic effect and the synergy index obtained for Fe3+ Sono photo catalysis was 2.05. Chemical oxygen demand (COD) analysis was used to study the degree of mineralization. After 180 min of reaction, the removal of COD was 15, 25.4 and 55.5% for UV/Fe3+, US/Fe3+ and UV/US/Fe3+ process, respectively. The degradation by photocatalysis and sonolysis followed pseudo first-order with respect to the concentration of AR14. Conclusions: The results showed that the Sono photo catalytic degradation and mineralization of AR14 in the presence of Fe3+ was synergistic, most likely because of the participation of Sono-Fenton and photo-Fenton reactions

Removal of Ortho-Toluidine from Industrial Wastewater by UV/TiO2 Process

In this research degradation and mineralization of Ortho-Toluidine (OT) in the wastewater of petrochemical industries was investigated by UV/TiO2 process in a batch recirculating photo reactor. The influence of different variables such as initial pH, amount of TiO2 and initial concentration of OT on the reaction rate was investigated. In optimum conditions (1.75 g/l of catalyst, pH at 7 and initial concentration of OT at 20 mg/l), 93.5% of pollutant and 57% of COD were removed in 180 min of reaction. The reaction rate represented by the mechanism of Langmuir-Hinshelwood was found to follow pseudo first-order kinetics. Degradation and mineralization of the OT were tested by HPLC and COD tests

Mathematical Modeling of 1, 3-Butadiene Polymerization Initiated by Hydrogen Peroxide

In this study, the modeling of polymerization of 1, 3-butadiene in the presence of hydrogen peroxide has been reported for the first time. For this purpose, the Method of double moments was applied. The modeling has been performed to investigate the effect of reaction condition on the properties of synthesized Polybutadiene, and the role of kinetic coefficients on the output of model i.e. sensitivity analysis. A comprehensive kinetic model was developed based on previous experimental studies. Then, the moment and population balance of the reactants were obtained. Modeling results were used to study the role of initiator concentration and the type of solvent in polymerization kinetics and final polymer properties. In addition, the sensitivity of modeling results in a transfer to the initiator, radical coupling and finally transfer to polymer reactions was investigated. This study opens a way for the engineering of manufacturing the Hydroxyl-Terminated PolyButadiene (HTPB) process to obtain the desired products with optimized reaction conditions. Results show that initiator concentration and type of solvent are important in polymerization kinetics and properties of HTPBs. A higher amount of initiator increases radical concentration and consequently rates of bimolecular termination and at the lower level, rate of propagation, and polymer double bonds reactions