Advanced Materials Research Vols. 356-360

Abstract: In order to decrease coal dust pollution of industry square, two types of dust-controlling equipment of main fan diffuser of coal mine are designed by virtue of inertia separation and gravity sedimentation. On the basis of field conditions, the physical models of two equipments are constructed. In application of Computational Fluid Dynamics (CFD), dynamic and kinetic fields of two-phase flow in two equipments are researched. The results show that the application of dust control equipment of main fan diffuser is available approach of decreasing coal dust pollution in industry square of coal mine.

Abstract: This document discussed a biofilter packing with complex filler, which was inoculated by a kind of toluene-degrading microorganism. The toluene-degrading microorganism(JBJ-3), which was isolated from activated sludge from a wastewater treatment plant of refinery, was classified as Pseudomonas sp. initially by physiological and biochemical tests. The removal efficiency of JBJ-3 reached to 93.73% for 48h. Complex filler consisted of wood chip, peat and compost etc. It has high amounts of organic matter, high specific surface area, good water holding capacity, good permeability, varied microbial system, and contains intrinsic nutrients. The complex filler could inoculate Pseudomonas sp. JBJ-3 well. And under the different inlet concentrations of toluene, the overall removal efficiency had reached above 92%. And the biofilter packing complex filler showed a good resistance to shock load.

Abstract: The trass ceramisite and ceramisite coated by iron oxide or alumina have been carried out to adsorb the copper (25mg/l) inside wastewater. The results show that the removal rate of trass ceramisite is the lowest, and removal rate of the trass ceramisite coated by alumina is the highest with the removal rate up to 67%. The optimum conditions of Cu ²⁺-adsorption in wastewater by ceramisite coated by alumina are as follow: pH at 6, contact time for 40min, the amount of adsorbent at 12.5g/l.

Abstract: Two chinese bituminous coals used in coal-fired power plants are combusted under air conditions in a lab-scale drop tube furnace. The effects of minerals transformation on the formation of PM _2.5 are investigated during the combustion of coal blends. The collected PM were subjected to Computer controlled scanning electron microscopy (CCSEM) and High-resolution transmission electron microscopy(HRTEM) coupled with energy dispersive X-ray spectroscopy (EDX) analysis for determination of chemical species within them. The results show that PM _2.5 emissions are not linearly related to the wt.% of the parent coal or coal blends. Transformations of fine Si-Al mineral grains provided by the minerals in coal XQ into coarse particles (>2.5 μm in diameter) are responsible for the reduction of PM_1-2.5 during the combustion of coal blending. The transformed fine Si-Al particles are captured by the coarse Ca-Mg-Al-Si provided by the minerals in coal HT to form larger Ca-Mg-Al-Si particles (>2.5 μm in diameter). Increasing Ca and Mg concentration in coal blends enhances the liquid concentration produced during combustion and hence affects the emissions of PM1 and PM_1-2.5.Through adjusting the mineral compositions in coal blends, the reduction of PM1 and PM_1-2.5 emissions can be achieved during combustion.

Abstract: Because of the environmental danger of heavy metal ions, how to safely and efficiently remove them has became a research hot point. Compared with common methods, adsorption is a better treatment for heavy metal ions. In this paper, Cu ²⁺ was removed from aqueous solution by a kind of environmentally friendly cellulosic adsorption resin and adsorption performance was investigated. The effects of factors, such as adsorbent dosage and solution pH, on adsorption were investigated. Experimental results displayed that adsorption performed well in neutral solution, and removal was about 94% when used dosage of resin was 0.6 g/L and initial concentration of Cu ²⁺ was 25 mg/L. Cellulosic resin owned powerful adsorption capability for other heavy metal ions, also. Adsorption behavior abided by Langmuir adsorption isothermal model, and maximum adsorption capability and equilibrium constant was 71.43 mg/g and 1.22 L/g, respectively. Resin could be regenerated by 8% ammonia and regeneration ratio was 74% after 2.5 h.

Abstract: Chlorophenols is a kind of environmental endocrine disrupting chemicals (EDCs) and it is hard for the common methods to degrade or remove them, so how to decompose these pollutants has attracted researches’ attention. In this paper, a novel α-Ga₂O₃ was used to degrade 4-chlorophenol via photocatalytic reaction and degradation kinetics was investigated. The effects of main factors, such as dosage of α-Ga₂O₃ and pH of aqueous solution, on degradation were studied, and degradation kinetics was also established. Experimental results displayed that the optimal pH of aqueous solution was about 7.8 and almost 98% 4-chlorophenol was decomposed after 2 h, when the dosage of α-Ga₂O₃ was 0.4 g and the initial concentration of 4-chlorophenol was 20 mg/L (V=200 ml). Photocatalytic degradation of 4-chlorophenol with α-Ga₂O₃abided by first-order kinetics and half-life time was 20.4 min.

Abstract: In a diaphragm electrolyze system with a Ti/RuO₂/IrO₂ anode and the Pd/MWNTs gas diffusion cathode, the degradation of 4-chlorophenol was fully studied by the electrochemical reduction and the simultaneous oxidation of the cathode and anode. The results indicated that the optimization electrolyte concentration is 0.08 mol/L. The Cl- removal reached 94.8% after 80 min electrolysis with H2 feeding. After 120 min electrolysis, the removal of 4-chlorophenol in the anodic and cathode compartments were 98.5% and 90.6%, respectively. Additionally, the TOC removal reached 65% and 70% in the anodic and cathodic compartment respectively after 140 min. By the UV scanner analysis of the electrolyte, the 4-chlorophenol and benzoquinone were oxidized by the oxides formed on the cathode, while the benzoquinone was found accumulated in the anodic compartment.

Abstract: The uses of herbicides have become an integral part of modern agricultural systems. The intensive use of herbicides atrazine has resulted in serious environmental problems. We researched the microbial Remediation of Atrazine-contaminated soil by Rhizobium sp. DNS7 and Acinetobacter sp DNS32. The results found two strains had a high capability for degrading atrazine in soil and culture medium. The mixed strains was more efficient in the mineralization of atrazine than the isolated strain in soil. The result provided a effective way to remediate atrazine pollution soil.

Abstract: This paper studies through project cases the treatment effect of integrated technique of anaerobic filter and constructed wetland on domestic wastewater in military camps, and the method for preventing the blocking of anaerobic filter and constructed wetland packing. The results show that its average removal rate of COD, NH4+-N, TP and SS is 83.1%, 37.5%, 49.8% and 91.5% respectively, with effluent meeting the standard of Grade II in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002); as planned, two anaerobic filters, one for operation and the other laying fallow at a alternate period of 6 months, in combination of the design of spoil disposal, can effectively prevent the packing layer from being blocked; being preprocessed, anaerobic filter can effectively prevent the packing layer of constructed wetland from being blocked; in case of a certain difference in elevation, the integrated technique can achieve unpowered operation. Besides, it is easy to implement and manage at a low operational cost without professional technician, and can treat decentralized domestic wastewater, therefore, is suitable for camps.

Abstract: A new method to improve the adsorption ability of expanded graphite (EG) was introduced in this paper. EG was modified by nano magnesium hydroxide. Modified expanded graphite (MEG) was characterized by SEM, XRD and FTIR. Then, the removal rate of Pb (Ⅱ) rose to 99% from 60.51% on MEG, and the removal rate of Cr (Ⅵ) could reach at 23.9% from 12.36%.