Materials Science Forum Vols. 743-744

Abstract: More and more attention has been paid to soil contamination by heavy metals in recent years. Heavy metal contamination includes heavy metal - heavy metal contamination, heavy metal - organic contamination, and heavy metal nutrient contamination. In particular, soil contamination by cadmium (Cd) is the most typical one. In terms of the current remediation technologies, phytoremediation of Cd contaminated soil remains popular due to its low cost, environmental aesthetics and in-situ effective treatment. Therefore, screening-out and identification of Cd hyperaccumulators becomes a hotspot in this researching domain. In order to further improve the efficiency of phytoremediation, we have developed a variety of joint remediation technologies. Based on these work at home and abroad, we summed up the studying progress in this field. Some main researching contents and directions of phytoremediation for Cd contaminated soils were also proposed.

Abstract: Micro/nano-structural polyaniline were prepared by using thin glass tubes as template in the presence of α-SiW₁₁Co and ammonium persulfate, which were used as dopant and oxidant, respectively, in this study. The structure and morphology of Micro/nano-structural polyaniline were characterized by means of IR, UV-Vis spectrum, XRD pattern and SEM images. The conductivity and fluorescence property were determined, and thermal stability was studied. The experimental results showed that the conductivity of the materials was 0.86 S·cm^-1 at room temperature（20°C）. The images of scanning electron microscopy show that the materials have microspheres morphology. The spectra data indicate that polyaniline doped with α-SiW₁₁Co exhibits fluorescence property. The photocatalytic degradation of gentian violet on α-SiW₁₁Co/PANI in an aqueous solution was carried out to investigate the catalytic activity. The results indicated that the sensitizing effect of PANI can improve the light response of α-SiW₁₁Co and enhance the separation efficiency of electron and hole pairs which in turn promotes the photocatalytic ability of the composites materials. This novel photocatalyst exhibits very high photocatalytic activities to decompose gentian violet in aqueous system under 30W ultraviolet light irradiation. After extraction, the photocatalytic activity under UV irradiation and gentian violet degraded by 90.41% within 150 min.

Abstract: The supported [Bmim]₆PMo₉V₃O₄₀ was synthesised by using the ion liquid [Bmim]Cl and heteropoly acid H₆PMo₉V₃O₄₀, and was supported on the active carbon fibre.The results of FT-IR showed that the structure of Ionic liquid cation and anion heteropoly acid on the active carbon fibre did not changed during the synthesising and supporting of the [Bmim]₆PMo₉V₃O₄₀. The catalysts performance of [Bmim]₆PMo₉V₃O₄₀/ACF on Flue Gas Desulfurization was investigated. The investigation was focused on the influence of the capacity of [Bmim]₆PMo₉V₃O₄₀, the oxygen centent, and reaction temperature on [Bmim]₆PMo₉V₃O₄₀/ACF for flue gas desulfurization. The experimental results showed that the desulfurization rate was up to 100%, lasting for 100 minutes,the sulfur capacity was as high as 400 mg/g in 4h, as desulfurization codition for the oxygen centent of 8% and the temperature of 60°C.

Abstract: The adsorption of acid black dye NT on collagen fiber (CF) was studied, and the effects of temperature, pH, initial dye concentration, adsorbent dosage and reaction time on the dye adsorption were tested, respectively. The results indicated that the optimal temperature and pH of acid black dye NT absorption were 40°C and 2.0, respectively. For a certain concentration of dyeing, the adsorption capacity decreased with the increasing of adsorbent dosage, but increased along with the extension of the contact time. In addition, the adsorption isotherms and kinetics of acid black dye NT on CF were investigated. By comparison, it was found that the Freundlich equation and Pseudosecond-order kinetic model can better describe the adsorption behavior of acidic black dye on CF. Thermodynamic parameters, such as G, H and S were determined to be-3.445 kJ/mol, 11.2 kJ/mol and 59.6 J/(mol·K), respectively. The results indicated that the adsorption was a spontaneous endothermic nature.

Abstract: It is known that heavy metals are taken up and translocated by plants to different degrees. Phytoremediation, the use of plants to decontaminate soil by taking up heavy metals, shows considerable promise as a low-cost technique and has received much attention in recent years. However, its application is still very limited due to low biomass of hyperaccumulators, unavailability of the suitable plant species and long growing seasons required. Therefore, to maximize phytoextraction efficiency, it is important to select a fast-growing and high-biomass plant with high uptake of heavy metals, which is also compatible with mechanized cultivation techniques and local weather conditions. Trees in particular have a number of attributes (e.g. high biomass, economic value), which make them attractive plants for such a use. This paper reviews the potential for the phytoremediation of heavy metal-contaminated land by trees. In summary, we present the research progress of phytoremediation by trees and suggest ways in which this concept can be applied and improved.

Abstract: To extend the duration of KMnO₄ in the groundwater in situ remediation, controlled release oxidant was prepared by dispersing the KMnO₄ particles in the molten paraffin wax. Preparation conditions, including KMnO₄ particles size, ultrasonic treatment time and the weight ratio of KMnO₄ to wax (P/W) were optimized. The results showed that the average volume particle size of 13.20 μm and ultrasonic treatment of 10 min contribute to the most uniform dispersion of the KMnO₄ particles in the molten paraffin wax. The scanning electron microscope (SEM) images showed that the increased amount of KMnO₄ caused the crushed structure of paraffin wax, which resulted in the higher porosity of wax to contain more KMnO₄. The KMnO₄ loading amount increased significantly along with the increase of the P/W. However, the loading amount almost reached saturation by 609.63 mg/g when the P/W increased to 2/1. The releasing characteristics of the samples in the distilled water and the KMnO₄ residual amount at different radial distance in the sample were examined by the bench scale tests. The releasing of KMnO₄ could be divided into four periods and stable release took place after 40 d. Controlled release KMnO₄ oxidant with P/W at 1/35 was used to remove COD in the leachate and 82.9% removal efficiency was obtained after 120 d treatment.

Abstract: In this paper, the spent Activated Carbon (AC) which came from caramel plant was regenerated by the method of microorganism and chemistry. The optimal regeneration method was the combination of microorganism regeneration and NaOH regeneration. The optimal regeneration condition was treated by microorganism in 60 min at temperature of 35 °C and in NaOH (dosage was 6%). The optimal ultrafine grinding time was 5 h at 1200 rpm by adding 5 Triethanolamine, the effect of ultrafine grinding was better and the minimal size distribution was D90 3.82µm, D50 1.62 µm. the study ofAC surface modification was explored while combining the similar characteristics of AC and Carbon Black in its structure and composition. The possibility of reusing the spent AC was studied and the mechanical performance of rubber with modified AC was 43~44% higher than that of unmodified AC. The modified AC was characterized by Scanning electron microscope (SEM).

Abstract: In order to provide a new technique for macrophytes use, this study evaluated the effect of biomass content on properties of biomass briquetting. Take lime as the binder, the best addition of biomass was 45%. In such case the drop strength of giant reed and reed briquetting reached maximum 55% and 74% respectively, and water impermeability reached minimum 15% and 7% respectively. Calorific value of biomass briquetting was between 11.1 MJ/kg and 14.9 MJ/kg and ash content was between 38.6% and 45.5%. Take giant reed briquetting as the example, 25% of money could be saved if briquetting replaced coal and people in Nansi Lake would get $159,333,333 a year. Also biomass briquetting could bring some environmental benefit including purifying water, slowing the greenhouse problems and acid rain. This study could provide a support for wetland restoration of the ecosystem, water quality, and the improvement of the economic benefits.

Abstract: LCA method was used to model the life cycle of cement manufacturing with multi-stage combustion and low-NOx Burner technology applied as its low-NOx system. The life cycle is from the coal and raw materials transportation, through the coal and raw meal grinding, to the clinker incineration, and finally the flue gas including NOx to the air atmosphere. The functional unit is 1 tonne clinker. Data for cement produced in MSC and LNB technology is analyzed. The data is collected from the real clinker production situation and the measurement is taken in 12 hours continuously.

Abstract: The synthetic methods that starch graft copolymerized with lactic acid have been preliminary studied with catalysis of ordinary chemical reagents by one-step, and the structure of starch/lactic acid graft copolymer was characterized by IRH-NMRXRD and SEM et al. The experimental results show that sodium hydroxide (NaOH), zinc oxide (ZnO) and stannous chloride (SnCl₂) so on can catalyze the graft copolymerization of starch with lactic acid successfully, it will provide a simple synthetic process to prepare starch/lactic acid graft copolymer.