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The extensive use of Cr(VI) in many industries and the disposal of Cr(VI)-containing wastes have resulted in Cr(VI)-induced environmental contamination. Cr(VI) compounds are associated with increased cancer risks; hence, the detection of toxic Cr(VI) compounds is crucial. Various methods have been developed for Cr(VI) measurement, but they are often conducted offsite and cannot provide real-time toxicity monitoring. A microbial fuel cell (MFC) is an eco-friendly and self-sustaining device that has great potential as a biosensor for in situ Cr(VI) measurement, especially for wastewater generated from different electroplating units. In this study, Exiguobacterium aestuarii YC211, a facultatively anaerobic, Cr(VI)-reducing, salt-tolerant, and exoelectrogenic bacterium, was isolated and inoculated into an MFC to evaluate its feasibility as a Cr(VI) biosensor. The Cr(VI) removal efficiency of E. aestuarii YC211 was not affected by the surrounding environment (pH 5–9, 20–35 °C, coexisting ions, and salinity of 0–15 g/L). The maximum power density of the MFC biosensor was 98.3 ± 1.5 mW/m2 at 1500 Ω. A good linear relationship (r2 = 0.997) was observed between the Cr(VI) concentration (2.5–60 mg/L) and the voltage output. The developed MFC biosensor is a simple device that can accurately measure Cr(VI) concentrations in the actual electroplating wastewater that is generated from different electroplating units within 30 min with low deviations (−6.1% to 2.2%). After treating the actual electroplating wastewater with the MFC, the predominant family in the biofilm was found to be Bacillaceae (95.3%) and was further identified as the originally inoculated E. aestuarii YC211 by next generation sequencing (NGS). Thus, the MFC biosensor can measure Cr(VI) concentrations in situ in the effluents from different electroplating units, and it can potentially help in preventing the violation of effluent regulations.

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Equilibrium tie line data have been determined at (298.15, 323.15, 348.15, and 373.15) K for the ternary liquid–liquid equilibria (LLE) of heptane + (toluene or m-xylene) + sulfolane systems. The relative mutual solubility of toluene is higher than that of m-xylene in heptane + sulfolane mixtures. The tie line data were correlated with the UNIQUAC and NRTL models. The calculated values based on the UNIQUAC model were found to be better than those based on the NRTL model; the average root-mean-square deviation between the phase composition obtained from experiment and that from calculation was 0.5111 for UNIQUAC compared to 0.6475 for NRTL. The values of selectivity and the distribution coefficient were derived from the equilibrium data at different temperatures.

In this study, the effect of different operating conditions including on the extraction of palladium (II) from HCl solution by using tri-n-octylmethylammonium chloride (Aliquat 336)/kerosene was evaluated at 25˚C. Different stripping reagents such as AlCl 3 , KCl, NaCl, NH 4 Cl, HCl, and thiourea were evaluated. The results indicate that the mixture of chloride and thiourea would lead to the highest stripping conversion for palladium (II) (i.e. >99%). The extraction distribution ratios were found to increase with the increase in the extractant concentration and decrease with the concentration of chloride ion. In addition, the compositions of palladium complexes in organic phase and equilibrium constant of recovered extraction reaction were estimated. Furthermore, the recovery efficiency of palladium(II) in acidic chloride solution was performed and compared.

ABSTRACT:A composite was prepared that contained diglycidyl ether of tetrabromobisphenol A (DGETBA) and 1,5-di(2,3-epoxypropoxy)naphthalene (A), 4,4Ј-bis(2,3-epoxypropoxy)benzylideneaniline (B), or 4,4Ј-bis(2,3-epoxypropoxy)biphenyl (C), and then was cured using different ratios of dicyandiamide (DICY). The results of DSC, TGA, coefficient of thermal expansion, dielectric constant, and dissipation factor testing of the composite epoxy resins were analyzed, and investigation of the copper-clad laminate using the composite epoxy resins as prepreg was also performed. Additionally, moisture absorption, peel strength, arc resistance, comparative tracking index, and flammability of the copper-clad laminate were examined. Clearly, some of the physical or mechanical properties of the composite and the copper-clad laminate can be improved by optimal addition of naphthalene-phenyl-based epoxy.

New triptycene-containing polyamides were prepared from 1,4-bis(4-carboxyphenoxy)triptycene with aromatic diamines or from 1,4-bis(4-aminophenoxy)triptycene with aromatic dicarboxylic acids via the phosphorylation polyamidation reaction. These polyamides were essentially amorphous and showed a significantly increased solubility as compared with their analogs without the triptycene units. All the polyamides could be solution-cast into flexible and tough films. They also showed good thermal stability with glass transition temperatures of 252-295°C and 10 % weight loss temperatures higher than 540°C. These polyamides are considered to be promising processable hightemperature polymeric materials.