Microbial electrochemical technologies (METs) are emerging green processes producing useful products from renewable sources without causing environmental pollution and treating wastes. The separator, an important part of METs that greatly affects the latter's performance, is commonly made of Nafion proton exchange membrane (PEM). However, many problems have been identified associated with the Nafion PEM such as high cost of membrane, significant oxygen and substrate crossovers, and transport of cations other than protons protons and biofouling. A variety of materials have been offered as alternative separators such as ion-exchange membranes, salt bridges, glass fibers, composite membranes and porous materials. It has been claimed that low cost porous materials perform better than PEM. These include J-cloth, nylon filter, glass fiber mat, non-woven cloth, earthen pot and ceramics that enable non-ion selective charge transfer. This paper provides an up-to-date review on porous separators and plots directions for future studies.
Mullets are dominant fishes in the catch composition in the southern coasts of the Caspian Sea and after (Rutilus frisii kutum Kamensky, 1901) have a worthy role in production of marine proteins and incomings of north provinces of Iran. Mullets stocks decreased dramatically in recent decades in the Caspian Sea and catch amount reached from 6446 MT on 2002 to 2151 MT in 2012. Mysterious mortalities occurred in wild mullet (Liza auratu) and (Liza saliens) in Iranian waters of Caspian Sea in recent years. Regarding to investigation of causative agent of mentioned outbreak about 322 suspected samples were collected from coastal capture sites of Iranian north provinces in 2008 till 2011. Moribund fish revealed skin darkening, erratic swimming, belly-up at rest and high distension of swim bladder. Target tissues such as brain and eye were removed and then fixed for histopathology and TEM assay. Widespread and massive vacuolation were observed in brain, spinal cord, retina and optical nerve and intracytoplasmic vacuoles and virus particles in retina. So concerning to clinical signs, histopathological and TEM findings, it could be concluded that nodavirus-like agent could be probable cause of mass mortality of wild mullet in Iranian waters of the Caspian Sea.
A novel nano-bio composite polypyrrole (PPy)/kappa-carrageenan(KC) was fabricated and characterized for application as a cathode catalyst in a microbial fuel cell (MFC). High resolution SEM and TEM verified the bud-like shape and uniform distribution of the PPy in the KC matrix. X-ray diffraction (XRD) has approved the amorphous structure of the PPy/KC as well. The PPy/KC nano-bio composites were then studied as an electrode material, due to their oxygen reduction reaction (ORR) ability as the cathode catalyst in the MFC and the results were compared with platinum (Pt) as the most common cathode catalyst. The produced power density of the PPy/KC was 72.1 mW/m(2) while it was 46.8 mW/m(2) and 28.8 mW/m(2) for KC and PPy individually. The efficiency of the PPy/KC electrode system is slightly lower than a Pt electrode (79.9 mW/m(2)) but due to the high cost of Pt electrodes, the PPy/KC electrode system has potential to be an alternative electrode system for MFCs.
Two compounds consisting of electron-accepting trifluoromethylphenyl moiety and electron-donating phenoxazine and phenothiazine moieties were designed and synthesized via Buchwald-Hartwig coupling reaction. Thermal, photophysical, and electrochemical properties of the compounds are discussed. Only compound with phenothiazine form molecular glass, with glass transition temperatures of 90 °C. The geometry and electronic characteristics of the compounds were substantiated within density functional theory (DFT). 10,10'-(2-(Trifluoromethyl)-1,4-phenylene)bis(10H-phenoxazine) shows efficient thermally activated delayed fluorescence with high spin-orbit coupling values. 10,10'-(2-(Trifluoromethyl)-1,4-phenylene)bis(10H-phenothiazine) as efficient room-temperature phosphor shows high oxygen sensitivity.