Air pollution is a widespread health problem associated with respiratory symptoms. Continuous exposure monitoring was performed to estimate alveolar and tracheobronchial dose, measured as deposited surface area, for 103 children and to evaluate the long-term effects of exposure to airborne particles through spirometry, skin prick tests and measurement of exhaled nitric oxide (eNO). The mean daily alveolar deposited surface area dose received by children was 1.35 × 103 mm2. The lowest and highest particle number concentrations were found during sleeping and eating time. A significant negative association was found between changes in pulmonary function tests and individual dose estimates. Significant differences were found for asthmatics, children with allergic rhinitis and sensitive to allergens compared to healthy subjects for eNO. Variation is a child's activity over time appeared to have a strong impact on respiratory outcomes, which indicates that personal monitoring is vital for assessing the expected health effects of exposure to particles.

The environmental behavior of carbon nanotubes (CNTs) and humic acid (HA) is a prominent concern, but effect of functionalities on their sorption is not clear yet. Functionalized multi-walled CNTs (MCNT15) and HA were used to study their sorption behavior. Sorption rate of HA to MCNTs was dominantly controlled by its diffusion from liquid-MCNT boundary to MCNT surfaces. The sorption is in the sequence of MCNT15 > MCNT15-NH2 > MCNT15-OH > MCNT15-COOH > MCNT15-Ni, which was dependent on their surface area and meso- and macro-pore volume. The functionalities of MCNTs regulated the sorption by affecting their interaction mechanisms (i.e., H-bonding, π–π, and hydrophobic interaction). Additionally, the amount of these functionalities on the MCNT surface reduced indirectly the sorption sites due to the steric hindrance. Electrostatic repulsion deceased the sorption of HA by MCNTs with increasing pH. This study demonstrated the importance of functionalities on the MCNTs for the sorption of HA.

A simulated oxidation technique was used to examine the impacts of degradation on the surface properties of biochar and the potential implications of the changes in biochar properties were discussed. To simulate the short- and long-term environmental degradation, mild and harsh degradation were employed. Results showed that after mild degradation, the biochar samples showed significant reductions in surface area and pore volumes. After harsh degradation, the biochar samples revealed dramatic variations in their surface chemistry, surface area, pore volumes, morphology and adsorption properties. The results clearly indicate that changes of biochar surface properties were affected by biochar types and oxidative conditions. It is suggested that biochar surface properties are likely to be gradually altered during environmental exposure. This implies that these changes have potential effects for altering the physicochemical properties of biochar amended soils.

The impact of three commercially available nanoparticles (NPs) on trichloroethylene (TCE) adsorption onto granular activated carbon (GAC) was investigated. TCE adsorption isotherm and column breakthrough experiments were conducted in the presence and absence of silicon dioxide, titanium dioxide, and iron oxide nanoparticles. A rapid small-scale column test (RSSCT) was assessed for its ability to predict TCE adsorption in pilot-scale GAC in the presence and absence of NPs. Zeta potential of the three NPs and the GAC were measured. Particle size distribution of the NP dispersions was analyzed as a function of time. The surface area and the pore size distribution of the virgin and the exhausted GAC were obtained along with transmission electron microscopy and Fourier transform infrared spectroscopy analysis. The effect of NPs was found to be a function of their zeta potential, concentration, and particle size distribution. Due to their electrical charge, NPs attached to the GAC and blocked the pores and thus reduced the access to the internal pore structure. However, due to the fast adsorption kinetics of TCE, no effect from the three NPs was observed in the isotherm and kinetic studies. The RSSCT, on the other hand, accurately predicted the pilot-column TCE breakthrough in the presence of NPs.

In the present paper, undoped and Ni-doped TiO2 sol-gel nanopowders have been prepared in order to establish the effect of Ni dopant on both material structure and photocatalytic properties. Two dopant concentrations of the transition metal (0.5 and 2 wt%) have been tested. The influence of both Ni dopant concentration and temperature of thermal treatment on the prepared powders has been followed using X-ray diffraction (XRD) method. A proper program has been used in order to establish the complete XRD structural characterization (lattice parameters, crystrallite sizes, internal strains). X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) coupled with surface area electron diffraction (SAED) techniques have completed the structural and morphological characterization of the prepared materials. Magnetic measurements and photocatalytic activity determinations have also been performed. The correlation between the results of the mentioned methods has been accomplished, and the detailed interpretation of the relation between structure and photocatalytic activity measurements has been done. The concentration of 0.5 wt% of Ni dopant ensures a better photocatalytic activity, compared to that of 2 wt%. © 2013 Springer Science+Business Media Dordrecht.

A novel porous biomorph-genetic composite of α-Fe₂O₃/Fe₃O₄/C (PBGC-Fe/C) with eucalyptus wood template was prepared, characterized and tested for its sorption capacity of As(V) from aqueous solution. The result indicated that the PBGC-Fe/C material retained the hierarchical porous structure of eucalyptus wood with three different types of pores (widths 70∼120, 4.1∼6.4 and 0.1∼1.3 μm) originating from vessels, fibres and pits of the wood, respectively. Its surface area was measured to be 59.2 m²/g. With increasing initial As(V) concentration from 5 to 100 mg/L, the amounts of As(V) sorbed on the pulverized PBGC-Fe/C sorbent (<0.149 mm) increased from 0.50 to 4.01 mg/g at 25 °C, from 0.50 to 4.83 mg/g at 35 °C and from 0.50 to 4.19 mg/g at 45 °C, and the corresponding removal rates decreased from 99.97 to 40.10 % at 25 °C, 99.95 to 48.40 % at 35 °C and 99.92 to 42.05 % at 45 °C. At the initial concentrations of 5, 10 and 50 mg/L, the sorption capacities for the unpulverized PBGC-Fe/C sorbent (>3 mm) were determined to be 0.50, 0.99 and 2.49 mg/g, respectively, which exhibited a similar average value to those of fine particles or nanoparticles of iron oxides. The sorption could well be described by the pseudo-second-order kinetic equation. The equilibrium data were found to follow Freundlich as well as Langmuir isotherms.

The present paper examines the phosphate adsorption from aqueous solutions onto goethite, bentonite, and bentonite–goethite system. The properties of the materials were studied by X-ray diffraction (XRD), attenuated total reflectance (ATR), and NMR spectra and by the measurement of the specific surface area, the point of zero charge (p.z.c.) and the pore-specific volume. ATR and NMR spectra of bentonite and bentonite–goethite system show peaks which correspond to tetrahedrally and octahedrally coordinated Al. The specific surface area of the system differs according to the appropriate method used, while system’s p.z.c. is higher than bentonite and lower than goethite. The pore-specific volume of bentonite–goethite system is higher than that of bentonite or goethite. According to XRD spectrum of bentonite–goethite system, goethite coats the (001) spacing of bentonite while the coating of (010) plane of bentonite is limited. The crystallinity of the system decreases and the negative permanent charge increases. Phosphate adsorption experiments took place at different pH (3.8–9.0) and concentrations (40.3–443.5 μmol L⁻¹) and constant capacitance model was applied to describe adsorption. A ligand exchange mechanism characterizes the model because the charge is divided among adsorbate and adsorbent. The constant capacitance model describes the adsorption mechanism in all examined pH. This model can be utilized in such systems using the surface protonation-dissociation constant of goethite and showing the exact shape of the adsorption isotherms for different pH values. Τhe produced low-cost bentonite–goethite system presents the highest adsorption of P per kilogram of goethite.

Adsorption potentials of native and amine-modified plant biomass of Alyssum caricum for the removal of Reactive Green 19 (RG-19) and Reactive Red 2 (RR-2) dyes from aqueous solutions were studied. The adsorbents were characterized before and after modification process using Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and potentiometric titration analysis. Modification of the surface of A. caricum biomass with hexamethylenediamine (HMDA) showed an increase of 1.18-fold in its surface area. Batch studies illustrated that dye adsorption were highly dependent on different process variables, pH, initial dye concentration of solution, adsorbent dosage, and temperature. The maximum adsorption capacities of the native and amine-modified adsorbents were 27.6 and 63.4 mg/g adsorbent for RG-19 dye and 16.5 and 36.8 mg/g adsorbent for RR-2 dye, respectively. The adsorption of both dyes on the native and amine-modified plant biomass correlated well with the Langmuir and Temkin isotherm equations as compared to Freundlich and D-R equations. The calculated thermodynamic parameters for both native and amine-modified adsorbents showed that the adsorption was feasible, spontaneous, and exothermic. The information gained from these studies was expected to indicate whether native and amine-modified adsorbents can have potential to be used for the removal of other dyes from wastewaters. © 2013 Springer Science+Business Media Dordrecht.

Boric acid-treated and sulfur ion-doped multi-modified TiO₂ films with high photocatalytic activities were prepared on soda–lime glass (Na₂O · CaO · 6SiO₂) substrates via the sol–gel method. The as-prepared specimens were characterized using high-resolution field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence spectra, UV–vis diffuse reflectance spectroscopy, and Brunauer–Emmett–Teller surface area. The photocatalytic activities of the films were evaluated by degradation of organic dyes in aqueous solutions. Compared with boric acid treatment and sulfur surface doping, the integration of both methods gave the best results. It is believed that high photocatalytic activity is correlated with the microstructure of the TiO₂ film.

Adsorption of fluoroquinolone antibiotics using sludge-derived biochar made of various wastewater sludges was investigated. The sludge-derived biochar had relatively large Brunauer–Emmet–Teller specific surface areas that were beyond 110.0 m² g⁻¹ except the biochar made from the sludge collected from traditional sludge drying bed. The mesopore capacity was more than 57 % of the total pore capacity of all sludge-derived biochar except that made from the sludge dried through traditional sludge drying bed technique. High adsorption capacity of sludge-derived biochar was observed with a highest adsorption capacity of 19.80 ± 0.40 mg g⁻¹. High correlation between the adsorption capacity of sludge-derived biochar and the volatile content in the sludge source was observed. The Freundlich model (r ² values were in the range of 0.961–0.998) yielded the best fit with the experimental data of all the produced biochar. Fluoroquinolone antibiotics were readily adsorbed onto sludge-derived biochar. These findings suggest a new approach for the pollution control of fluoroquinolone antibiotics using low-cost sludge-derived biochar.