Arsenic Removal from Mine Waters with Sorption Techniques

Potential low-cost sorption materials (mostly industrial by-products) were screened for removal of arsenic from mine effluent water. First, the maximum adsorption capacities were determined in batch tests with various liquid to solid ratios. The highest arsenic sorption capacity, 46 mg As/g of sorption material, was measured for cast iron chips. The most promising materials were also studied in batch tests that assessed the reaction kinetics and in kinetic column tests for their behavior in a filter or reactive barrier application. The column tests revealed the cast iron chips caused clogging in the percolation column when operating with real mine water. A commercial ferric oxi-hydroxide sorption material developed for As removal for drinking water showed good As removal in the column tests. Around 10,000 bed volumes of mine process water containing 2 mg/L of arsenic was treated with this material, and treated water concentrations ranged between 0 and 0.05 mg/L before breakthrough. The measured adsorption capacity for the commercial ferric oxi-hydroxide sorption material was 8.3 mg As/g.     

Effects of de-icing chemicals sodium chloride and potassium formate on cadmium solubility in a coarse mineral soil

Excessive use of sodium chloride (NaCl) as de-icing chemical causes environmental problems, such as elevated chloride concentrations in groundwater. On vulnerable sites, this can be avoided by using alternative organic de-icing chemicals, such as potassium formate (KHCOO). The environmental impacts of KCHOO are, however, not well known. This study reports the potential effects of NaCl and KCHOO on mechanisms controlling the mobility of cadmium (Cd) in roadside soils as a result of vehicular traffic. Changes in the solubility of Cd in a coarse mineral soil treated with these two de-icing chemicals were studied in a 50-day incubation experiment under four different moisture and temperature combinations and an initial soil Cd concentration of 3 mg kg(-1). After incubation, the distribution of soil Cd into different fractions was analyzed using a sequential extraction method. Soil pH and soil redox potential were recorded and the occurrence of Cd-Cl complexes in the soil was estimated using published stability constants. During incubation, KCHOO lowered the soil redox potential, but this was not accompanied by a decrease in the sorption capacity of oxides and the release of oxide-bound Cd into soil solution. On the other hand, elevated pH (from 4.3 to 6.7-8.5) in the formate treatments increased the sorption of Cd onto the oxide surfaces (up to 80% of total sorbed Cd). In the NaCl treatments, cation competition and formation of Cd-Cl complexes increased the water-soluble Cd fraction. Consequently, the amount of bioavailable Cd was 3.5 times smaller in the KCHOO than in the NaCl treatments.     

A Method for Evaluating Coke Hot Strength

The strength of coke is of major importance for efficient blast furnace operation. There are only a few studies related to compressive coke hot strength, possibly due to experimental difficulties. In this work, it has been demonstrated that the Gleeble thermomechanical simulator is suitable for evaluating coke hot strength and offers many benefits compared to purpose‐built devices reported in the literature. This finding could open coke hot strength research to a wider number of scientists. The compressive hot strength of coke was evaluated at 1000 and 1600°C by testing 50 samples at both temperatures. The yield strength and ultimate strength of the coke were, respectively, 46 and 20% lower at 1600°C than 1000°C. Stress–strain curves showed that the coke was brittle at 1000°C but partially plastic at 1600°C. The significantly lower coke strength at 1600°C could help explain the smaller coke lump size found near the tuyere level in quenched blast furnaces.     

Characteristics and the environmental acceptability of the natural stone quarrying waste rocks

The paper summarises the results of a study by the Geological Survey of Finland on the potential use of waste rocks from natural stone quarry production. Petrographic, chemical, mechanical and physical tests were undertaken on granite, rapakivi granite, migmatite, syenite, diorite, gabbro, anorthosite gabbro, schist and soapstone from 33 dimension stone quarries in Finland. The results indicate the waste rocks of Finnish natural stone quarries can generally be considered environmentally sound with potential uses in other industries.     

Efficient Management of Fines in the Stock Flow prior to Headbox in Paper, Board, and Tissue Production

Fines represent a significant volume of biobased wood material and filler, which is of significant importance to sheet quality. New imaging technology reveals the true nature of the behavior of fines in the retention process. This study illustrates new chemical mixing systems, novel and efficient flash mixing methods, and active measurement and automation systems pertaining to efficient management of fines in the stock flow prior to headbox in paper, board, and tissue production, which can reduce additive, fresh water, energy consumption, and the carbon footprint of production to improve sustainability and provide novel opportunities for fines and filler management.     

Infrared laser ablation atmospheric pressure photoionization mass spectrometry

In this paper we introduce laser ablation atmospheric pressure photoionization (LAAPPI), a novel atmospheric pressure ion source for mass spectrometry. In LAAPPI the analytes are ablated from water-rich solid samples or from aqueous solutions with an infrared (IR) laser running at 2.94 μm wavelength. Approximately 12 mm above the sample surface, the ablation plume is intercepted with an orthogonal hot solvent (e.g., toluene or anisole) jet, which is generated by a heated nebulizer microchip and directed toward the mass spectrometer inlet. The ablated analytes are desolvated and ionized in the gas-phase by atmospheric pressure photoionization using a 10 eV vacuum ultraviolet krypton discharge lamp. The effect of operational parameters and spray solvent on the performance of LAAPPI is studied. LAAPPI offers ~300 μm lateral resolution comparable to, e.g., matrix-assisted laser desorption ionization. In addition to polar compounds, LAAPPI efficiently ionizes neutral and nonpolar compounds. The bioanalytical application of the method is demonstrated by the direct LAAPPI analysis of rat brain tissue sections and sour orange (Citrus aurantium) leaves.     

Self‐Assembled Peptide–Polyfluorene Nanocomposites for Biodegradable Organic Electronics

Based on self‐assembly and mimicking strategies occurring in nature, peptide nanomaterials play a unique role in a new generation of hybrid materials for the electronics of the 21st century. This report describes the functionalization of diphenylalanine (FF)‐based micro/nanostructures with blue‐emitting conducting polymers of the polyfluorene (PF) family. The FF:PF polymer nanocomposites are synthesized by a liquid‐vapor phase method. Electron microscopy images reveal di‐octyl‐substituted PF (PF8) to bind better to the FF micro/nanotubes in comparison with ethyl‐hexyl PF (PF2/6), which influences its optical properties. Molecular dynamics simulations of FF nanotubes with monomeric units of PFs show that PF8 favors greater proximity to the grooves on the surface of the nanotubes due to a higher van der Waals interaction energy compared to PF2/6. The FF:PF nanocomposites are further utilized in light‐emitting diodes. Biodegradability tests from FF:PF8 nanocomposite films show more than 80% weight loss in 2 h by enzymatic action compared to PF8 pristine films, which do not degrade. Self‐assembly of FF nanostructures with organic semiconductors opens up a new generation of biocompatible and biodegradable materials in organic electronics.     

Organization of type III collagen in benign and malignant ovarian tumors. An immunohistochemical study

BACKGROUND: Abnormal interaction with the extracellular matrix is a basic property of malignant cells. Type III collagen is a major constituent of the extracellular matrix of soft tissues. METHODS: Deposition of the aminoterminal propeptide of type III procollagen (PIIINP) was studied in benign (n = 41), borderline (n = 4), and malignant (n = 32) human ovarian tumors using the avidin-biotin-immunoperoxidase technique and affinity-purified antibodies to human PIIINP: It was then compared with the serum PIIINP concentrations of the patients at the time of operation. RESULTS: In malignant tumors, the distribution of PIIINP was irregular both close to the epithelial cancer cells and further away, in the stroma. Another feature typical of malignant tumors was the varying staining intensity of the PIIINP-positive fibers. The benign tumors were characterized by a regular organization and an intensive staining of PIIINP: Borderline tumors showed a slightly decreased staining intensity and altered PIIINP distribution. A significant positive correlation was found between the PIIINP concentration in serum and the degree of irregularity in the distribution of PIIINP: CONCLUSIONS: These preliminary results indicate that malignant transformation in ovarian tumors is associated with disintegration of adjacent collagenous structures and with alterations in type III procollagen metabolism, which also leads to increased serum PIIINP levels. They suggest that biochemical or immunohistochemical detection of the PIIINP antigen could be clinically useful in ovarian tumors.     

Atomic layer deposition on polymer based flexible packaging materials: Growth characteristics and diffusion barrier properties

One of the most promising areas for the industrial application of atomic layer deposition (ALD) is for gas barrier layers on polymers. In this work, a packaging material system with improved diffusion barrier properties has been developed and studied by applying ALD on flexible polymer based packaging materials. Nanometer scale metal oxide films have been applied to polymer-coated papers and their diffusion barrier properties have been studied by means of water vapor and oxygen transmission rates. The materials for the study were constructed in two stages: the paper was firstly extrusion coated with polymer film, which was then followed by the ALD deposition of oxide layer. The polymers used as extrusion coatings were polypropylene, low and high density polyethylene, polylactide and polyethylene terephthalate. Water vapor transmission rates (WVTRs) were measured according to method SCAN-P 22:68 and oxygen transmission rates (O₂TRs) according to a standard ASTM D 3985. According to the results a 10 nm oxide layer already decreased the oxygen transmission by a factor of 10 compared to uncoated material. WVTR with 40 nm ALD layer was better than the level currently required for most common dry flexible packaging applications. When the oxide layer thickness was increased to 100 nm and above, the measured WVTRs were limited by the measurement set up. Using an ALD layer allowed the polymer thickness on flexible packaging materials to be reduced. Once the ALD layer was 40 nm thick, WVTRs and O₂TRs were no longer dependent on polymer layer thickness. Thus, nanometer scale ALD oxide layers have shown their feasibility as high quality diffusion barriers on flexible packaging materials.