The fate and lability of added soluble Ag in soils over time was examined by measurement of labile metal (E-value) by isotopic dilution using the 110mAg radioactive isotope and the solid-phase speciation of Ag by X-ray absorption near edge structure (XANES) spectroscopy. After two weeks of ageing the E-values for Ag decreased by 20–90% with a further decrease of 10–40% after six months. The overall decrease in labile Ag for all soils after the 6 month ageing period was 50–100%. The ageing was more rapid and pronounced in the alkaline soils. XANES results for Ag in soils indicated that for the majority of soils the added Ag+ was reduced to metallic Ag over time, and associations with Fe-oxohydroxides and reduced S groups in organic matter also decreased Ag lability. Strong positive correlations were found between metallic Ag and non-labile Ag and between organic carbon and Ag bonded with S species.

We examined copper (Cu) absorption, distribution and toxicity and the role of a silicon (Si) supplementation in the bamboo Phyllostachys fastuosa. Bamboos were maintained in hydroponics for 4 months and submitted to two different Cu (1.5 and 100 μm Cu2+) and Si (0 and 1.1 mM) concentrations. Cu and Si partitioning and Cu speciation were investigated by chemical analysis, microscopic and spectroscopic techniques. Copper was present as Cu(I) and Cu(II) depending on plant parts. Bamboo mainly coped with high Cu exposure by: (i) high Cu sequestration in the root (ii) Cu(II) binding to amino and carboxyl ligands in roots, and (iii) Cu(I) complexation with both organic and inorganic sulfur ligands in stems and leaves. Silicon supplementation decreased the visible damage induced by high Cu exposure and modified Cu speciation in the leaves where a higher proportion of Cu was present as inorganic Cu(I)S compounds, which may be less toxic.

The distributions of dissolved methane in the central Bohai Sea were investigated in November 2011, May 2012, July 2012, and August 2012. Methane concentration in surface seawater, determined using an underway measurement system combined with wavelength-scanned cavity ring-down spectroscopy, showed marked spatiotemporal variations with saturation ratio from 107% to 1193%. The central Bohai Sea was thus a source of atmospheric methane during the survey periods. Several episodic oil and gas spill events increased surface methane concentration by up to 4.7 times and raised the local methane outgassing rate by up to 14.6 times. This study demonstrated a method to detect seafloor CH4 leakages at the sea surface, which may have applicability in many shallow sea areas with oil and gas exploration activities around the world.

Novel photocatalysts i.e., metallic nickel and zinc oxide nanoparticles embedded in the carbon-shell ((Ni–ZnO)@C) have been used for photocatalytic splitting of seawater to generate H2. The (Ni–ZnO)@C core–shell nanoparticles having the Zn/Ni ratios of 0–3 were prepared by carbonization of Ni2+- and Zn2+-β-cyclodextrin at 673K for 2h. To increase the collision frequency of water and photoactive sites within the carbon-shell, Ni and ZnO are partially etched from the (Ni–ZnO)@C core–shell to form yolk–shell nanoparticles with a H2SO4 solution (2N). By X-ray diffraction spectroscopy, mainly Ni and ZnO crystallites are observed in the core– and yolk–shell nanoparticles. The sizes of the Ni and ZnO in the (Ni–ZnO)@C nanoreactors are between 7 and 23nm in diameters determined by TEM and small angel scattering spectroscopy. Under a 5-h UV–Vis light irradiation, 5.01μmol/hgcat of H2 are yielded from photocatalytic splitting of seawater effected by (Ni–ZnO)@C nanoreactors.

The Cunha Canal watershed, which is located in the municipality of Rio de Janeiro, suffered severe environmental degradation in recent decades due to rapid urban population growth. However, this substantial growth did not result in social development; instead, it exacerbated existing environmental and social problems. This study aimed to evaluate the pollution of the Canal do Cunha and Guanabara Bay, using GIS for mapping based on the result of the heavy metal concentrations obtained by spectrometry (ICP-OES). The analyzed data were monitored at five collection points. Five heavy metals (Cd, Pb, Cu, Ni and Zn) were evaluated. The results showed that the waters of the Cunha Canal watershed and the west side of Guanabara Bay have been altered and degraded. The concentration of heavy metals in the water was lower than the concentration in the sediments. The behaviors of the studied metals differed during the rainy and dry periods.

Silver-doped TiO₂(Ag-TiO₂) immobilized onto polystyrene (PS) waste was prepared using a thermal attachment method. Its efficiencies as a photocatalyst under UVA light (λ = 365 nm) for the removal of Cr(VI), methylene blue, Escherichia coli, and Aspergillus niger from water were studied. The results showed that Ag-TiO₂-PS material removes pollutants at significantly high rates and especially posseses strong disinfection properties. The morphological study of Ag-TiO₂-PS material was carried out using X-ray diffraction, scanning electron microscope, and energy dispersive X-ray spectroscopy. The catalyst can be prepared using waste PS employing a simple immobilization method and it is highly effective for the removal of biological and chemical impurities from drinking and underground water supplies.

Activated natural siderite (ANS) was used to investigate its characteristics and mechanisms of As(V) adsorption from aqueous solution. Batch tests were carried out to determine effects of contact time, initial As(V) concentration, temperature, pH, background electrolyte, and coexisting anions on As(V) adsorption. Arsenic(V) adsorption on ANS well-fitted pseudo-second-order kinetics. ANS showed a high-adsorption capacity of 2.19 mg/g estimated from Langmuir isotherm at 25 °C. Thermodynamic studies indicated that As(V) adsorption on ANS was spontaneous, favorable, and endothermic. ANS adsorbed As(V) efficiently in a relatively wide pH range between 2.0 and 10.0, although the removal efficiency was slightly higher in acidic conditions than that in basic conditions. Effects of background electrolyte and coexisting anions were not significant within the concentration ranges observed in high As groundwater. Results of XRD and Fe K-edge XANES analysis suggested ANS acted as an Fe(II)/(III) hybrid system, which was quite effective in adsorbing As from aqueous solution. There was no As redox transformation during adsorption, although Fe(II) oxidation occurred in the system. Two infrared bands at 787 and 872 cm⁻¹after As(V) adsorption suggested that As(V) should be predominantly adsorbed on ANS via inner-sphere bidendate binuclear surface complexes.

A new solid phase extraction method was developed for the preconcentration and determination of rare earth elements (REEs) (Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Lu, Ce) in water samples. The method is based on the sorption of REE ions onto the 2,6-pyridinedicarboxaldehyde-functionalized Amberlite XAD-4 resin at pH 7.0, followed by the elution with 2 mL of 1.0 mol L⁻¹ HNO₃ solution and determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The main parameters affecting preconcentration, including sample pH, sample and eluent flow rate, and sample volume, have been investigated in detail. Under the optimum conditions (pH 7.0, sample flow rate of 1.0 mL min⁻¹, and eluent flow rate of 4.0 mL min⁻¹), detection limits between 0.011 and 0.298 μg L⁻¹ for a 25 mL sample volume and 0.006 and 0.149 μg L⁻¹ for a 50 mL sample volume were obtained. The sorption capacities for the resin were found to range between 49.0 μmol g⁻¹ (for Lu) and 66.7 μmol g⁻¹ (for Sm). The method was validated by analysis using a surface water certified reference material (SPS-SW2 Batch 127). The proposed method was successfully applied to the determination of REEs in tap water and seawater samples. The recovery values for the spiked water samples were in the range of 90.0–101.7 %.

The novel adsorbent Cu-impregnated activated coke (CAC) has been successfully prepared using a Cu(NO₃)₂solution impregnated activated coke (AC). The optimum preparation conditions of CAC are the concentration of Cu(NO₃)₂of 0.1 mol/L, pH of 6, loading time of 4 h, and loading temperature of 333 K. The characterizations of CAC are analyzed by N₂adsorption, X-ray diffraction, scanning electron microscope, and energy dispersive X-ray spectroscopy. Also the adsorption behavior of CAC to organic materials in TNT red water is studied. The adsorption data are simulated by Freundlich isotherm and Langmuir isotherm. Below 333 K Freundlich isotherm is more suitable, while Langmuir isotherm model is more fitted when the temperature is higher than 333 K. The adsorption kinetics follows a pseudo second-order model, and thermodynamic analysis indicates an endothermic and spontaneous adsorption processes, and the process appears to be controlled by the chemisorption process. Chemical oxygen demand of 85.34 % can be removed as CAC prepared under optimized conditions is used as absorbent. In summary, CAC has excellent absorption characteristics and can be used in the removal of organic materials from TNT red water.

Recent scientific findings and legislations have clearly highlighted the need for comprehensive approaches and methods to evaluate natural dust contributions to an urban atmosphere. The evaluation of chemical compositions of airborne aerosols is of these methods that may employ several advanced analytical techniques and processes. In this paper, an episodic appearance of Saharan dust incursion over a megacity (Istanbul, Turkey) was investigated using size segregated particulate matter (PM) samples in fine and coarse fractions collected between February 27 and March 8, 2009. The Saharan impact was investigated using satellite observations, backward air trajectory statistics, and chemical analyses of the collected samples. In the chemical analyses, Fourier transform infrared coupled with attenuated total reflectance (ATR-FTIR) spectroscopic method was used to determine the functional groups, namely, alcohols, ammonium, aliphatic carbons, carbonyls, organonitrates, nitrate, silicate, silica, kaolinite, and calcium carbonate. Among all the measured functional groups, it was clearly seen that the intensities of IR peaks related to silicate, silica, kaolinite, and calcium carbonate were associated with the increased mass concentrations during the impact period. The observed IR peaks at 1,030 and 800 cm⁻¹for silicate ions in the samples can be used as an indicator of the large dust incursion into the atmosphere (e.g., Saharan dust episodes observed in Istanbul). This study showed that the ATR-FTIR spectroscopic method is a fast and convenient method to identify these peaks and the IR method in general is useful for identifying a large dust incursion into the atmosphere.