Crystalline phases and physical properties of modified stoneware body with glaze sludge

Ceramic stoneware body has been modified with ceramic and glass industrial wastes by replacing 25–100% as flux in the formula. The effects of solid wastes added to the bodies were studied after firing in the temperature range 950–1280 °C. The physical properties of linear shrinkage, bulk density, apparent porosity, water absorption and 3-point bending strength were determined. A composition which related to the general stoneware properties was found when using soda-lime cullet and glaze sludge. It had a firing range lowered to 1050–1100 °C. SEM results demonstrated the sintered microstructure increased in density with increase in solid waste in the modified body. XRD results after firing showed the crystalline phases comprised of mullite, albite calcian and quartz. Thermal expansion was measured in the range 6.53–6.67 × 10^?6 K^?1 at 30–500 °C. The modified bodies were capable of forming prototype products by slip casting and jiggering.     

A Minimized Chemoenzymatic Cascade for Bacterial Luciferase in Bioreporter Applications

Bacterial luciferase (Lux) catalyzes a bioluminescence reaction by using long-chain aldehyde, reduced flavin and molecular oxygen as substrates. The reaction can be applied in reporter gene systems for biomolecular detection in both prokaryotic and eukaryotic organisms. Because reduced flavin is unstable under aerobic conditions, another enzyme, flavin reductase, is needed to supply reduced flavin to the Lux-catalyzed reaction. To create a minimized cascade for Lux that would have greater ease of use, a chemoenzymatic reaction with a biomimetic nicotinamide (BNAH) was used in place of the flavin reductase reaction in the Lux system. The results showed that the minimized cascade reaction can be applied to monitor bioluminescence of the Lux reporter in eukaryotic cells effectively, and that it can achieve higher efficiencies than the system with flavin reductase. This development is useful for future applications as high-throughput detection tools for drug screening applications.     

Batch and column adsorption of perfluorooctane sulfonate on anion exchange resins and granular activated carbon

Perfluorooctane sulfonate (PFOS) has been detected widely in the natural water matrix and is persistent, bioaccumulative, and toxic. To prevent the adverse effects of PFOS contamination on human health and the environment, effective removal techniques are needed. Adsorption is considered an effective technique for PFOS removal. In this study, five anion exchange resins and granular activated carbon (GAC) were examined to evaluate their performance for the removal of PFOS in both batch and column experiments. Experimental adsorption data for all of the adsorbents exhibited a high correlation with the Freundlich isotherm (R² = 0.95 – 0.98). Most of the anion exchange resins demonstrated a higher adsorption capacity than the GAC. PFA300 had the highest adsorption capacity (455 mg/g). Continuous adsorption of PFOS was performed in column experiments using the same adsorbents that had been used in the batch experiments. The experimental breakthrough curves were set at C/C₀ = 0.1. PFA300 showed the longest operation time before reaching the breakthrough point. The Yoon and Nelson model was used to predict the half‐saturation time of the anion exchange resins. Moreover, the anion exchange resins exhibited high recovery of PFOS by an organic solvent. Continuous PFOS adsorption on a column can be achieved using anion exchange resins for water/wastewater treatment. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39782.     

Regeneration and reusability of anion exchange resin used in perfluorooctane sulfonate removal by batch experiments

Perfluorooctane sulfonate (PFOS) has been increasingly considered an environmental micropollutant in recent years. The adsorption of PFOS by anion exchange resins and granular activated carbon was studied in this work. Additionally, the regeneration and reusability of the selected resin were further studied. The equilibrium adsorption data were fitted well by the Freundlich isotherm for all adsorbents. PFA300 had the highest adsorption capacity (455 mg/g) and the fastest adsorption rate. Regeneration studies of PFA300 were conducted using different types of regeneration solutions. The regeneration efficiency of PFA300 exceeded 99%. Regenerated PFA300 was reused as an adsorbent and showed high PFOS removal efficiency for six cycles. In this study, PFA300 had the highest adsorption capacity as well as good regeneration and reusability. Therefore, PFA300 is a promising adsorbent that can be used to remove PFOS in aqueous solution. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 884‐890, 2013     

Hybrid Plasticizers Enhance Specificity and Sensitivity of an Electrochemical-Based Sensor for Cadmium Detection

In addition to their use as an additive to improve physical properties of solvent polymeric membranes, plasticizers have a considerable impact on the specificity and sensitivity of membrane-modified electrochemical sensors. In this work, we aim at the hybridization of two different plasticizers using the electropolymerization technique in the development of a cadmium(II)-selective electrochemical sensor based on screen-printed gold electrode along with cyclic voltammetric measurement. At this point, we first screen for the primary plasticizer yielding the highest signal using cyclic voltammetry followed by pairing it with the secondary plasticizers giving rise to the most sensitive current response. The results show that the hybridization of DOS and TOTM with 3:1 weight ratio (~137.7-μm-thick membrane) renders a signal that is >26% higher than that from the sensor plasticized by DOS per se in water. The solution of 0.1 mM hydrochloric acid (pH 4) is the optimal supporting electrolyte. In addition, hybrid plasticizers have adequate redox capacity to induce cadmium(II) transfer from bulk solution to the membrane/water interfaces. Conversion of voltammetric signals to semi-integral currents results in linearity with cadmium(II) concentration, indicating the irreversible cadmium(II) transfer to the membrane. The DOS:TOTM hybrid sensor also exhibits high sensitivity, with a limit of detection (LOD) and limit of quantitation (LOQ) of 95 ppb and 288 ppb, respectively, as well as greater specificity towards cadmium(II) than that obtained from the single plasticizer sensor. Furthermore, recovery rates of spiked cadmium(II) in water samples were higher than 97% using the hybrid plasticizer sensor. Unprecedentedly, our work reports that the hybridization of plasticizers serves as ion-to-electron transducer that can improve the sensor performance in cadmium(II) detection.