Treatment of oily port wastewater effluents using the ultraviolet/hydrogen peroxide photodecomposition system.

This paper presents the nonselective degradation of mechanically pretreated oily wastewater by hydrogen peroxide (H2O2) in the presence and absence of UV irradiation. The effect of chemical oxidation on wastewater biodegradability was also examined. The exclusive use of H2O2 photolyzed by daylight results in quite efficient degradation rates for the low peroxide concentrations used. Higher hydrogen peroxide concentrations inhibit degradation of organic contaminants in the wastewater. The degradation rates of all contaminants are relatively high with an advanced oxidation system (UV/H2O2), but degradation efficiencies are not distinguishably different when 20 or 45 minutes of UV irradiation is used. The excess of H2O2 used in the process can inhibit phenolic degradation and may lead to the formation of a new phenolic fraction. The biodegradability of port wastewater did not increase significantly following the application of the advanced oxidation process.     

Modeling of adsorption isotherms and kinetics of uranium sorption by magnetic ion imprinted polymers

Application of magnetic U(VI) ion imprinted polymers (IIPs) coated on magnetic nanoparticles was investigated for pre-concentration and determination of U(VI) ions in aqueous solutions. The scanning electron micrographs revealed the microporosity of the adsorbent. Uranium leaching was successful as the energy-dispersive X-ray spectra showed. The Brunauer–Emmett–Teller (BET) surface area improved by more than 13-fold (83.1 and 6.2 m² g^?1 for the leached and unleached magnetic IIP, respectively). U(VI) uptake was optimized using batch experiments with parameters affecting the uptake performance, such as initial uranium concentration, pH, contact time, and adsorbent dose investigated. Pseudo-second-order kinetics and the Langmuir isotherm model best fitted the experimental data. The maximum adsorption capacity of uranium onto the activated magnetic IIP reached 5.4 mg g^?1. The selectivity order was determined to be U(VI) > Ni(II) > Th(IV).     

The potential of Berkheya coddii for phytoextraction of nickel,platinum, and palladium contaminated sites

The study involved assessing the potential of the native plant species (Berkheya coddii) for the phytoextraction of nickel, palladium, and platinum contaminated sites. Plant and soil samples were randomly collected from Barberton area, near Agnes mine, Mpumalanga Province, South Africa. Samples were analysed for total nickel, palladium, and platinum concentrations together with other elements found in the soil and in the plants' roots, and leaves. Soil versus leaves and soil versus roots uptake of these metals by the plant were compared. The mean concentration of nickel in the leaves/canopy was found to be 13,980?±?10,780?mg?kg^?1?dry mass, in the roots it was 2046?±?789?mg?kg^?1 dry mass, and in the soil it was 1040?±?686?mg?kg^?1?dry mass. This resulted in a mean concentration ratio in the leaves to soil of 13.44. The platinum mean concentration in the leaves was 0.22?±?0.15?mg?kg^?1?dry mass, in the roots it was 0.14?±?0.04?mg?kg^?1?dry mass, and in the soil it was 0.04?±?0.03?mg?kg^?1?dry mass. This resulted in a mean concentration ratio in the leaves to soil of 5.5. Palladium was found to have a mean soil concentration of 0.07?±?0.045?mg?kg^?1?dry mass. The mean concentrations in the roots and in the leaves were 0.18?±?0.07 dry mass and 0.71?±?0.52?mg?kg^?1?dry mass, respectively. This gave a mean concentration ratio in the leaves to soil of 10.1 for palladium. Other elements that were found to have a mean concentration ratio in the leaves to soil of around 2.5 or above are sodium, potassium, magnesium, calcium, and sulfur. Berkheya coddii was found to be most efficient in accumulating nickel, palladium, and platinum from the soil. The results for the first time revealed that the plant may have the potential to uptake platinum and palladium; both metals are in the same group of the periodic table as nickel.     

Application of capillary electrophoresis combined with a modified BCR sequential extraction for estimating of distribution of selected trace metals in PM2.5 fractions of urban airborne particulate matter

The capillary electrophoresis (CE) method combined with a sequential extraction was applied to determine the distribution of Fe, Zn, Cu, Mn and Cd in urban ambient air PM2.5 samples. PM2.5 was collected on Teflon filters with dichotomous sampler, and the modified extraction procedure following the BCR leaching procedure was used to chemically fractionate metals into "easily exchangeable" with water, "acid extractable" with 0.11 mol/l acetic acid, "reducible" with 0.1 mol/l hydroxylamine hydrochloride acidified to pH 2.0 with nitric acid, and "oxidisable" with oxidation by 8.8 mol/l hydrogen peroxide (H2O2) followed by extraction with 1.0 mol/l ammonium acetate. Based on the obtained results it was concluded that the application of the studied methodology provides chemical fractionation data that reflect the general sources and potential health hazards of the studied metals.