Advanced Materials Research Vols. 1010-1012

Abstract: An automatic counting method for microalgal cells were proposed using digital image processing with characteristics of microalgae microscopic image considered. Firstly, the microalgae image was pretreated with graying, and was then applied the median filtering to remove the noise. Secondly, the image was applied Bot-hat conversion to enhance the contrast. Thirdly, the image was segmented with Otsu algorithm, and was then applied morphological operations. Finally, the binary image segments representing microalgal cells were labeled and counted. The results of experiments showed that this method was simple, efficient and accurate in counting microalgal cells in the microscopic image.

Abstract: Surface functionalization of graphitic carbon nitride (g-C₃N₄) through self-assembly is an effective way to improve the photocatalytic activity and to couple with chemical catalytic process. Herein, we report that Fe (III)-citrate complex molecules are assembled on the surface of g-C₃N₄ to improve the photocatalytic activity by coupling with Fenton reaction. The iron (III) species attached on the surface of g-C₃N₄ are in the form of complex. The Fe (III)-citrate complex shows little impact on the bulk structures of g-C₃N₄. In the dark, assembly of Fe (III)-citrate complexes on g-C₃N₄ (Fe (III)-Cit/g-C₃N₄) exhibits no activity for degrading the Rhodamine B (RhB) solution under the assistance of H₂O₂. But, it shows high catalytic activity with degradation efficiency of 100% for RhB solution (10 mg L^-1) under the simulated solar light irradiation for 30 minutes. Furthermore, the adsorption capacity and photocatalytic activity are retainable during the following 5 cycles. The retainable stability and enhanced catalytic activity of the assembly of Fe (III)-citrate complexes on g-C₃N₄ pave the ways to design advanced photocatalysts by employing supermolecular interaction.

Abstract: In the paper we first discussed the principle of wastewater treatment by iron-carbon micro electrolysis. And the experimental methods were stated clear soon afterwards. Then we designed the micro electrolysis orthogonal experiments. Discussion of influences of related factors on waste water treatment followed. The main factors are cerium ion additive quantity, ratio of La³⁺/Ce⁴⁺ and pH in wastewater. The experimental results show that 1) The sequence of factors influence on wastewater micro-electrolysis treatment is Ce⁴⁺ > pH > La³⁺ > iron/carbon ratio; 2) The lanthanum and cerium ions have a synergistic effect in the wastewater treatment, and cerium ion plays a main role; 3) When pH is 6, COD removal rate arrives at maximum 89%, however when the pH is in the case of too high or too low, the effect of sewage treatment is not good.

Abstract: TiO₂ nanorod array films with or without Nb doping grown directly on transparent conductive glass (FTO) were prepared by a facile hydrothermal method. The films were characterized by means of field emission scanning electron microscopy (FE-SEM) with energy-dispersive x-ray spectra (EDS), X-ray diffraction (XRD) and the X-ray photoelectron spectroscoy (XPS). The electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and transient photocurrent were investigated in a three-electrode system with TiO₂ nanorod array film served as the photoanode. The photoelectrocatalytic activity of the films was evaluated by the oxidation of glucose under UV irradiation. The results show that both the pure and Nb-doped TiO₂ nanorods perpendicularly grown on FTO substrate are rutile phase. The resistance of the TiO₂ nanorod array photoanode is decreased significantly by Nb doping. The steady-state photocurrent (i_ss) for glucose oxidation at Nb-doped TiO₂ nanorod array film is much higher than that at the pure one. The enhanced photoelectrocatalytic activity of the Nb-doped TiO₂ nanorods could be attributed to the enhanced charge transport ability.

Abstract: Phosphorus contamination in aquatic system was a widespread problem in Zhejiang province due to the excess use of detergent, agrochemicals and other organic phosphorus chemicals. Volcanic rock, an adsorbent with porous structure and large surface area, was applied for phosphorus removal in wastewater. The results showed that the phosphorus removal rate and equilibrium time had positive correlation with the initial phosphorus concentration, while the volcanic rock particle size could also affect the adsorption performance as volcanic rock with smaller particle size used to have a larger cation exchange capacity and higher surface area. Both Langmuir adsorption and the Freundlich adsorption happened throughout phosphorus removal process, showing the strong capacity and capability of volcanic rock as absorbent for phosphorus wastewater. It is promising to use volcanic rock in phosphorus water/wastewater purification systems due its large quantities and accessibility in nature.

Abstract: Morph genetic material is a kind of new material which can not only keep natural biological fine morphology and structure but also is given new characteristics and functions. At present, the main preparation methods for biomorphic materials are chemical solution impregnation method, sound chemical processing method, and nanocomposite solvent heating method, etc. Domestic and foreign researchers have been trying to use different templates to prepare for functional materials which have different tendencies. Compared with the conventional artificial materials, these materials show obvious superiority. Morph genetic material is a new type of functional materials, mainly used as catalyst and adsorbent, playing an important role in environmental protection.

Abstract: A series of Gd/N codoped nanoTiO₂ photocatalyst were synthesized to remove TOC in Power plant Boiler Make-up Water. The catalysts were prepared by sol–gel method and characterized by the means of XRD, TEM and UV-Vis DRS. Compared with pure TiO₂, the catalytic activity of the nanocomposite photo-catalyst was improved significantly. The experiment results show that the optimum amounts of Gd and N-codoped TiO₂ photocatalysts were 0.5 wt.% and 5mol %, respectively. Under the UV irradiation for 5 h at pH 3.0, the photocatalytic effect could be as high as 88% and the TOC removal efficiency was 81%, which indicates that photodegradation and mineralization of HA are synchronous, the two results correlate well.

Abstract: A novel fly ash cenospheres supported Pt–BiVO₄ composites (Pt–BiVO₄/FACs) photocatalysts were prepared by modified metalorganic decomposition process, followed by photochemical reduction. The composites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), and UV–vis diffused reflectance spectroscopy (DRS) techniques. The results indicate that the visible light absorption of the Pt–BiVO₄/FACs composite is greatly enhanced. The Pt element is present in the metallic form and disperses in the composite samples. Photocatalytic activities of the Pt–BiVO₄/FACs composites were evaluated by the methylene blue (MB) degradation under visible light irradiation. The results indicate that the photocatalytic efficiency is significantly improved after the Pt species was loaded and the 2 wt% Pt-loaded composite showed the highest photocatalytic activity.

Abstract: The corrosion behavior of Nickel base alloy was studied in municipal sludge treated by supercritical water oxidation (SCWO). The results showed that the corrosion rate of Nickel-base alloy Inconel600 in the temperature zone under 460°C is smaller, the surface oxide were mainly Cr₂O₃. The corrosion rate of Nickel-base alloy Inconel625 in the supercritical temperature zone is smaller, it formed more easily protective layers containing element Ni (main containing NiO and Ni (OH)₂) and had good heat resistance at higher temperature.

Abstract: The induction of tuberous roots of cassava in vitro is functional in MS medium containing 0.54 mM NAA, 0.44 mM BA and 3%-7% sucrose; meanwhile, the saccharide accumulation in the induced tuberous roots was increased with the sucrose content addition from 3%-7% in the inducible medium. Thus, the sucrose is an important factor for tuberous root induction in Cassava in vitro. The experimental results showed that the appropriate concentration of sucrose played a key role on the tuberous root induction in Cassava in vitro.