As Nuclear Magnetic Resonance Spectroscopic Investigation of the Thioarsenate Speciation in Strongly Alkaline Sulfidic Leaching Solutions.

Copper ores and concentrates thereof feature an increasingly notable content of impurities such as arsenic and other hazardous elements. As an alternative to the state-of-the-art partial roasting process, arsenic could be removed by the alkaline sulfide leaching of the copper concentrates. In order to optimize and understand the processes, knowledge of the speciation and oxidation states is essential.

Ferroelectric Properties of Polymer-Semiconductor Hybrid Material or Composite under Optical Excitation.

Polymer-semiconductor hybrid materials or composites have been investigated with respect to their microstructure, optical, photoconductive, and ferroelectric properties. For this purpose, either CdSe quantum dots or (Cd:Zn)S microparticles were dispersed in poly(vinylidenefluoride-trifluoroethylene) solution and hot pressed to films. In both material systems, the electrical conductivity and the polarization behavior could be controlled by the intensity of the optical excitation.

Sensing of chemical oxygen demand (COD) by amperometric detection-dependence of current signal on concentration and type of organic species.

The standard method to determine chemical oxygen demand (COD) with KCrO uses harmful chemicals, has a long analysis time, and cannot be used for on-site online monitoring. It is therefore necessary to find a fast, cheap, and harmless alternative. The amperometric determination of COD on boron-doped diamond (BDD) electrodes is a promising approach.

Influence of chemical structure of organic micropollutants on the degradability with ozonation.

The increasing environmental problems due to various organic micropollutants in water cause the search of suitable additional water treatment methods. Gaining experimental data for the large amount and variety of pollutants would consume a lot of time as well as economic and ecologic resources. An alternative approach is predictive quantitative structure-property relationship (QSPR) modeling, which establishes a correlation between the structural properties of a molecules with a biological, physical, or chemical property.

Prediction of degradability of micropollutants by sonolysis in water with QSPR - a case study on phenol derivates.

The increasing quantity and variety of organic contaminants discharged into surface and groundwater increase the necessity of additional and suitable water treatment methods, which can be incorporated into existing wastewater treatment plants. The huge variety of micropollutants and local variability of the composition of the organic load or matrix effects paired with multiple possible degradation processes lead to the requirement of a recommendation tool for the best possible water treatment method under given local conditions. Due to the diversity of physicochemical properties of micropollutants, such predictions are challenging.

Refining of Precious Metal Bearing Materials from Secondary Sources-Methanesulfonic Acid Leaching of Raw Silver Granules as a Promising Approach towards a Green Way of Silver Refining.

The state-of-the-art technology of raw silver refining in a silver nitrate-based electrorefining process (Moebius-electrolysis) is accompanied by several disadvantages, both from a technological and from an ecological point of view. In addition, increasing concentrations of critical impurities from secondary sources, like palladium, in raw silver are a further challenge for the future of silver refining. Thus, there is strong motivation for the development of an adequate, alternative process of raw silver refining to substitute the existing Moebius-electrolysis.

Influence of 3d Transition Metal Doping on Lithium Stabilized Na-β″-Alumina Solid Electrolytes.

Na-β″-alumina is the commercially most successful solid electrolyte due to its application in ZEBRA and NAS batteries. In this work, Li-stabilized Na-β″-alumina electrolytes were doped with 3d transition metal oxides, namely TiO, MnO, and NiO, in order to improve their ionic conductivity and fracture strength. Due to XRD and EDX measurements, it was concluded that Mn- and Ni-ions are incorporated into the crystal lattice of Na-β″-alumina.

Sodium Solid Electrolytes: NaAlO Bilayer-System Based on Macroporous Bulk Material and Dense Thin-Film.

A new preparation concept of a partially porous solid-state bilayer electrolyte (BE) for high-temperature sodium-ion batteries has been developed. The porous layer provides mechanical strength and is infiltrated with liquid and highly conductive NaAlCl salt, while the dense layer prevents short circuits. Both layers consist, at least partially, of Na-β-alumina.

Pyrocatalytic oxidation - strong size-dependent poling effect on catalytic activity of pyroelectric BaTiO nano- and microparticles.

Pyrocatalysis is an emerging advanced oxidation process for wastewater remediation with the potential for thermal energy harvesting and utilization. Although several studies explored the potential of new pyrocatalyst materials to degrade harmful organic water pollutants, the role of important material properties and electric poling procedures on the pyrocatalytic activity is still unclear. In this work, we investigate the interdependence between particle size, electric poling and pyrocatalytic activity of BaTiO3 powders with nominal particle sizes of 100, 200 and 500 nm by using the dichlorofluorescein redox assay.

Aluminum Melt Filtration with Carbon Bonded Alumina Filters.

The wetting behavior was measured for AlO-C in contact with AlSi7Mg with a conventional sessile drop test (vacuum, 950 °C and 180 min) and a sessile drop test with a capillary purification unit (vacuum, 730 °C and 30 min). The conventional test yielded contact angles of around 92°, whereas the sessile drop measurement with capillary purification showed a strongly non-wetting behavior with a determined apparent contact angle of the rolling drop of 157°. Filtration tests, which were repeated twice, showed that the AlO-C filter possessed a better filtration behavior than the AlO reference filter.

The sorption behaviour of amine micropollutants on polyethylene microplastics - impact of aging and interactions with green seaweed.

Microplastics are ubiquitous in the environment. Due to still rising global production, the emission of polymers into the environment and the abundance of microplastics have increased accordingly. Due to the long mineralization processes of microplastics, distribution in all compartments can be found.

Pyrocatalysis-The DCF assay as a pH-robust tool to determine the oxidation capability of thermally excited pyroelectric powders.

Pyrocatalysis uses thermally excited pyroelectric materials for the generation of reactive oxygen species in water. This unique feature allows it to harvest energy in the form of natural temperature gradients or waste heat from industrial processes in order to degrade organic pollutants at low costs. Its further development into an advanced oxidation process for water remediation is dependent on the availability of pH-robust and nonspecific redox assays for the determination of its oxidation capability.

A novel model for pyro-electro-catalytic hydrogen production in pure water.

The pyro-electro-catalytic induced generation of hydrogen gas is an environmentally friendly and sustainable way to convert excess thermal energy into a storable form. The main idea is to make use of spontaneous polarization of pyroelectric materials that can be altered by temperature changes. Thus, surface potential changes and subsequent electron exchange with surrounding molecules can be induced.

Degradation of endocrine disruptor bisphenol A by ultrasound-assisted electrochemical oxidation in water.

Micropollutants are becoming an increasing problem for the environment and wastewater treatment. One example is Bisphenol A (BPA), an endocrinic disruptor, which is widely used in plastic production. Due to its endocrine disrupting effects on aquatic (micro-)organisms and its ubiquity, in surface- and wastewater alike, adequate treatment techniques are necessary.