Biobsorbent properties of biosolids for aqueous zinc, manganese and cyanide removal

Biosolids were used to remove zinc, manganese and cyanide from mining wastewaters. The effect of aqueous parameters and reaction variables on contaminant biosorption was quantified. The mechanism of removal was adsorption onto amine and carboxyl functional groups. Immobilisation was investigated to overcome problems of swelling and disintegration of the biosolids.

Characterization and sorption ability of wool powder

This work focused on the characterisation of wool powders and their sorption capacity for dyes and metal ions. It provides new information to the field of wool and the potential use of wool to sorb contaminants from wastewater. It also suggests a new use for inferior and waste wool.

Fabricating and characterising silk powder for biomedical and sorption applications

This research developed a milling technology for ultrafine silk particles and designed novel biocompatible and biodegradable silk composites for repairing hard tissue defects. It also demonstrated high and rapid reversible ion binding properties of silk particles and thereby opened up their application opportunities as advanced green sorbents.

Metal ions and carcinogenesis

Metals are essential for the normal functioning of living organisms. Their uses in biological systems are varied, but are frequently associated with sites of critical protein function, such as zinc finger motifs and electron or oxygen carriers. These functions only require essential metals in minute amounts, hence they are termed trace metals. Other metals are, however, less beneficial, owing to their ability to promote a wide variety of eleterious health effects, including cancer. Metals such as arsenic, for example, an produce a variety of diseases ranging from keratosis of the palms and feet to cancers in multiple target organs. The nature and type of metal-induced pathologies appear to be dependent on the concentration, speciation, and length of exposure. Unfortunately, human contact with metals is an inescapable consequence of human life, with exposures occurring from both occupational and environmental sources. A uniform mechanism of action for all harmful metals is unlikely, if not implausible, given the diverse chemical properties of each metal. In this chapter we will review the mechanisms of carcinogenesis of arsenic, cadmium, chromium, and nickel, the four known carcinogenic metals that are best understood. The key areas of speciation, bioavailability, and mechanisms of action are discussed with particular reference to the role of metals in alteration of gene expression and maintenance of genomic integrity.

The influence of water and metal ions on the transport properties of Trihexyl(tetradecyl)phosphonium chloride

A recent study indicated that the water-saturated ionic liquid (IL) trihexyl(tetradecyl)phosphonium chloride ([P_6,6,6,14][Cl]) provided a viable electrolyte for a Mg-air battery. However, there is limited literature on the properties of IL-water mixtures as battery electrolytes. The physical properties of [P_6,6,6,14][Cl] were studied with the addition of both water and metal salts (M_gCl₂ and LiCl) using conductivity and self-diffusion coefficient measurements. The conductivity of the samples at low water concentrations is surprisingly enhanced by the addition of the metal salt, contrary to lithium IL electrolytes. It was also found that the conductivity of the IL was increased by an order of magnitude by saturation with water. NMR diffusion measurements were used to probe the behaviour of both the cation and the water in the mixtures. It was found that the addition of metal salts to the water-saturated [P_6,6,6,14][Cl] did not affect the transport properties of the water or cation.

Studies on the interaction between malanin and metal ions by fluorescence spectra methods

A novel protein with anti-tumor activities named malanin was isolated and purified from an endemic plant in Yunnan and Guangxi provinces. Effects of copper ion, silver ion and calcium ion on malanin and apo-malanin fluorescence spectra were studied. The results showed that copper ion leads to obvious statistic quenching of malanin and apo-malanin fluorescence. The dissociation constant of them from malanin and apo-malanin were about 2.37×10-4 and 2.66×10-4 mol·L-1, respectively. The silver ion did not have quenching action on malanin fluorescence, but it had statistic quenching effect on apo-malanin fluorescence, and its dissociation constant was 2.37×10-4 mol·L-1. Calcium ion did not have quenching action on malanin and apo-malanin fluorescence. It plays an important role in keeping malanin natural conformation.

Energy absorption and crushing behaviour of foam-filled aluminium tubes

The crushing behaviour and energy absorption of foam filled aluminium tubular structures were investigated using the quasi-static compressive tests. The crushing behaviour of the tubular structures changed due to foam filling. The energy absorption of the foam filled tubular structures was improved significantly. Foam filling caused an interaction effect between the tube and the foam during progressive crushing, leading to an increase in the mean crushing load compared to that of the foam or tube itself. This interaction effect might be affected by several parameters such as the density of the foam, the properties of both the foam material and tube material, and the thickness and outer diameter of the tube. In particular, the interaction effect essentially depended on the ratio of the mean crushing force of the foam to that of the tube.

Improved extraction of heavy metal ions using membrane technology

Investigates tha application of polymer membranes in industrial wastewater treatment. Several novel membrane systems have been developed. The new systems overcome the problems of low extractant capacity and slow rate of extraction of the traditional membrane system. These new systems offer significant scope for the treatment of industrial wastewater containing heavy metal ions.

Ionic conductivity of polymer gels deriving from alkali metal ionic liquids and negatively charged polyelectrolytes

We have prepared polymer gel electrolytes with alkali metal ionic liquids (AMILs) that inherently contain alkali metal ions. The AMIL consisted of sulfate anion, imidazolium cation, and alkali metal cation. AMILs were mixed directly with poly(3-sulfopropyl acrylate) lithium salt or poly(2-acrylamido-2-methylpropanesulfonic acid) lithium salt to form polymer gels. The ionic conductivity of these gels decreased with increasing polymer fraction, as in general ionic liquid/polymer mixed systems. At low polymer concentrations, these gels displayed excellent ionic conductivity of 10⁻⁴ to 10⁻³ S cm⁻¹ at room temperature. Gelation was found to cause little change in the ⁷Li diffusion coefficient of the ionic liquid, as measured by pulse-field-gradient NMR. These data strongly suggest that the lithium cation migrates in successive pathways provided by the ionic liquids.

Insights into the transport of alkali metal ions doped into a plastic crystal electrolyte

The application of organic ionic plastic crystals (OIPCs) as a new class of solid electrolyte for energy storage devices such as lithium batteries and, more recently, sodium batteries is attracting increasing attention. Key to this is achieving sufficient target ion transport through the material. This requires fundamental understanding of the structure and dynamics of OIPCs that have been doped with the necessary lithium or sodium salts. Here we report, for the first time, the atomic level structure and transport of both lithium and sodium ions in the plastic crystalline phases of an OIPC diethyl(methyl)(isobutyl)phosphonium hexafluorophosphate. These molecular dynamics simulations reveal two types of coordination geometries of the alkali metal ion first solvation shells, which cooperate closely with the metal ion hopping motion. The significantly different ion migration rates between two metal ion doped systems could also be related to the differences in solvation structures.

Graphene nanodots-encaged porous gold electrode fabricated via ion beam sputtering deposition for electrochemical analysis of heavy metal ions

All rights reserved. A graphene nanodots-encaged porous gold electrode via ion beam sputtering deposition (IBSD) for electrochemical sensing is presented. The electrodes were fabricated using Au target, and a composite target of Al and graphene, which were simultaneously sputtered onto glass substrates by Ar ion beam, followed with hydrochloric acid corrosion. The as-prepared graphene nanodots-encaged porous gold electrodes were then used for the analysis of heavy metal ions, e.g. Cu2+ and Pb2+ by Osteryoung square wave voltammetry (OSWV). These porous electrodes exhibited enhanced detection range for the heavy metal ions due to the entrapped graphene nanodots in 3-D porous structure. In addition, it was also found that when the thickness of porous electrode reached 40 nm the detection sensitivity came into saturation. The linear detection range is 0.009-4 μM for Cu2+ and 0.006-2.5 μM for Pb2+. Good reusability and repeatability were also observed. The formation mechanism and 3-D structure of the porous electrode were also investigated using scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectra (XPS). This graphene entrapped 3-D porous structure may envision promising applications in sensing devices.

Preparation and adsorption of phosphorus by new heteropolyacid salt–lanthanum oxide composites

In this article, we reported a new method in which molybdenum heteropolyacid salt was selected to mix with lanthanum oxide and bentonite, respectively, and the dipping method was used to prepare the new composites of heteropolyacid salt–lanthanum oxide, heteropolyacid salt–bentonite, and heteropolyacid salt–lanthanum oxide–bentonite. We observed that the composites have a better removal effect for phosphorus by control of the ratio and calcination temperature. The effect of quantity, adsorption time, phosphorus wastewater concentration, and pH value of composites on phosphorus adsorption was studied. We also found that the removal rate of phosphorus by the composite of heteropolyacid salt–lanthanum oxides increases up to 99.1% under the condition of 1:1 mass ratio and 500°C of calcination temperature. IR and XRD studies suggest that molybdenum heteropolyacid salt has been loaded to lanthanum oxide carrier successfully and heteropolyacid salt keeps the original Keggin structure. Heteropolyacid salt–lanthanum oxide has a good adsorption effect on phosphorus under the condition of 0.15 g of the composite, 90 min of adsorption time, phosphorus concentration of 50 mg L−1, and pH value of 3. The adsorption of phosphorus corresponds with the Langmuir isotherm model and Lagergren first-order kinetics equation. Therefore, the composite has excellent absorption ability and was competent in removing phosphorus with a low concentration from aqueous solution. It could be a great potential adsorbent for the removal of phosphorus in lakes, rivers, and reservoirs.

Absorption and desorption characteristics of fluoride in the calcareous and siliceous sand sheet aquifers of south-west Victoria, Australia

This study assessed the sustainability of utilising groundwater systems to
manage an aluminium smelter's fluoridated trade wastewater stream. Replacing ocean discharge of the wastewater with land irrigation is one option. Using a groundwater model (developed using MODFLOW incorporating parameter estimation software (PEST-ASP)), we found that most of the groundwater flow takes place through surface sands. Fluoride is adsorbed in these sands during the drier summer months, but desorption is rapid when winter rain flushes the aquifer. Underlying clays and other layers prevent significant contamination of the deeper aquifer.