Concentrating of Sugar Syrup in Bioethanol Production Using Sweeping Gas Membrane Distillation

Membrane distillation (MD) is a relatively new and underdeveloped separation process which can be classified as a green technology. However, in order to investigate its dark points, sensitivity analysis and optimization studies are critical. In this work, a number of MD experiments were performed for concentrating glucose syrup using a sweeping gas membrane distillation (SGMD) process as a critical step in bioethanol production. The experimental design method was the Taguchi orthogonal array (an L9 orthogonal one) methodology. The experimental results showed the effects of various operating variables, including temperature (45, 55, and 65 °C), flow rate (200, 400, and 600 ml/min) and glucose concentration (10, 30, and 50 g/l) of the feed stream, as well as sweeping gas flow rate (4, 10, and 16 standard cubic feet per hour (SCFH)) on the permeate flux. The main effects of the operating variables were reported. An ANOVA analysis showed that the most and the least influenced variables were feed temperature and feed flow rate, each one with 62.1% and 6.1% contributions, respectively. The glucose rejection was measured at 99% for all experiments. Results indicated that the SGMD process could be considered as a versatile and clean process in the sugar concentration step of the bioethanol production

Assessment of atomic force microscopy for characterization of PTFE membranes for membrane distillation (MD) process

The membrane distillation (MD) process is an emerging and under-developed technique, which is currently investigated for various applications, e.g. desalination and wastewater treatment. As specific membranes for MD are not yet commercially available, most of the applied membranes for MD experiments are those microfiltration membranes made of hydrophobic polymers. Characterization of such kinds of membranes is important in order to achieve a better and clearer understanding of their performance, which helps to fabricate specific membranes for the MD process. In this work, atomic force microscopy, which is a high-resolution technique and newly applied for characterization of MD membranes, has been used for the topographical study of different polytetrafluoroethylene membranes, which are typically recommended for various MD applications. The membranes were characterized for their pore size, pore size distribution, surface roughness, and nodule aggregate. Moreover, the other two important specifications, liquid entry pressure and surface hydrophobicity, were measured and compared. A sweeping gas MD experimental setup was used for solute rejection evaluation of the applied membranes by use of four different feed samples

Mechanism of action, resistance, synergism, and clinical implications of azithromycin

Background Azithromycin (AZM), sold under the name Zithromax, is classified as a macrolide. It has many benefits due to its immunomodulatory, anti-inflammatory, and antibacterial effects. This review aims to study different clinical and biochemisterial aspects and properties of this drug which has a priority based on literature published worldwide. Methods Several databases including Web of Science, Google Scholar, PubMed, and Scopus were searched to obtain the relevant studies. Results AZM mechanism of action including the inhibition of bacterial protein synthesis, inhibition of proinflammatory cytokine production, inhibition of neutrophil infestation, and macrophage polarization alteration, gives it the ability to act against a wide range of microorganisms. Resistant organisms are spreading and being developed because of the irrational use of the drug in the case of dose and duration. AZM shows synergistic effects with other drugs against a variety of organisms. This macrolide is considered a valuable antimicrobial agent because of its use as a treatment for a vast range of diseases such as asthma, bronchiolitis, COPD, cystic fibrosis, enteric infections, STIs, and periodontal infections. Conclusions Our study shows an increasing global prevalence of AZM resistance. Thus, synergistic combinations are recommended to treat different pathogens. Moreover, continuous monitoring of AZM resistance by registry centers and the development of more rapid diagnostic assays are urgently needed

CO2/CH4 Separation via Polymeric Blend Membrane

CO2/CH4 gas separation is a very important applicatable process in upgrading the natural gas and landfil gas recovery. In this work, to investigate the membrane separation process performance, the gas permeation results andCO2/CH4 separation characteristics of different prepared membranes (via blending different molecular weights of polyethylene glycol (PEG) as a modifier with acrylonitrile-butadiene-styrene (ABS) as a backbone structure) have been studied. Furthermore, SEM analysis was carried out for morphological investigations. The effect of PEG content on gas transport properties on the selected sample was also studied. The effect of pressure on CO2 permeation was examined and showed that at the pressure beyond 4 bar, permeability is not affected by pressure. The results showed that more or less in all cases, incorporation of PEG molecules without any significant increase in CH4 permeability increases the CO2/CH4 selectivity. From the view point of gas separation applications the resultant data are within commercial attractive rang