Advanced Materials Research Vols. 610-613

Abstract: A single-chambered and double-chambered microbial fuel cell (MFC) with refinery oil wastewater as its fuel was constructed respectively to investigate the feasibility of electricity generation and oil pollutants degradation using microbial fuel cell. Results indicated that the refinery oil waste water could be used as fuel in MFCs to generate electricity, the oil pollutants could be degraded by MFCs and the efficiency of double-chambered MFC was better; the main composition of pollutants in the solution influx and effluent of MFCs was changed and processes which were similar to anaerobic fermentation were proceeded.

Abstract: The unreasonable treatment of used automotive electronic control components can result in great damage to the environment and resource wastage. Therefore, there is an extremely urgent demand to develop a recycling program for these components. The Chinese scholars are developing the used automotive electronic control components recycling research. The recycling key technologies include: non-destructive high-efficiency dismantling and green clean technology, test technology and equipment, adjust technology, reliability testing techniques and quality assurance specifications. This study introduces the latest developments of these key technologies in accordance with China’s actual conditions, and then discusses the development direction.

Abstract: Recovering nitrogen and phosphorus through struvite crystallization from swine wastewater has gained increasing interest. However, effluents of anaerobic digested swine wastewater contains other constituents including complex and hardly definited organic compounds, which may hinder the formation of struvite crystal and affect the purity of the precipitates by forming other insoluble minerals. Struvite precipitation was carried out at laboratory scale by adding magnesium chloride and potassium hydrogen as external sources of magnesium and phosphorus to equal Mg: N: P molar ratio, respectively, and regulating the pH at 9.5 in the absence and presence of organic compounds. Exceeded 70% phosphate and ammonium reduction were obtained. The recovered products were detected and analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and chemical methods, which were proved to be struvite crystals. The soluble organic compounds had less than 6% changes in amount during struvite precipitation and it was proved that the removal of TCOD during the precipitation of struvite may be attributed to the co-precipitation of struvite. The results indicate that struvite precipitation could be a viable method of ammonium removal in the presence of organic compounds from anaerobically digested swine manure.

Abstract: After washing, milling and calcining, the graphite rods recycled from waste dry batteries were used as raw material to prepare expandable graphite by chemical oxidation (using acetic anhydride as inserting and potassium dichromate as oxidant), the expanded graphite was prepared from the obtained expandable graphite by microwave radiation (MW) at 1000W for 60s.The characterization of infrared spectroscopy (IR) and scanning electron microscopy (SEM) of obtained expanded graphite have been discussed. The results show that it is feasible to prepare expanded graphite using graphite rods recycled from waste dry batteries.

Abstract: Leachate is a high concentration organic wastewater, and microbial fuel cell (MFC) is capable of decomposing and treating organic pollutants directly. Single-chamber MFC using landfill leachate as anolyte was built to get rid of BOD and ammonia-nitrogen organic pollutant in leachate. The use of MFC led to the treatment of the biodegradable organic pollutant of municipal solid waste leachate and the production of electricity. The biofilm was detected on the MFC anode carbon felt, the voltage and power output were achieved 292.7± 5 mV and 2375.1mW.m-2. The suitable running time was about 10 days, when the BOD and ammonia-nitrogen removal efficiencies were achieved about 93.0% and 84.1 %, respectively.

Abstract: The effects of the oxidation of potassium ferrate and the flocculation on cresol wastewater water were evaluated. This research aimed at determining the optimum conditions for the COD removal rate duing cresol wastewater water process. The results showed that potassium ferrate dosage of 1.1g/L, the pH value of 5, reaction time 15min, m-cresol initial concentration of 200 mg/L were the optimum conditions. Under the optimum conditions, COD removal rate was over 67%.

Abstract: The research of dimethylbenzene and butylacetate from industrial spent solvent oil by batch distillation was studied, and the batch distillation experiment was by pretreated material. The effects of separation temperature and reflux ratio on separation efficiency were investigated,and compared the new tower with the old one. The experimental results showed that: when the reflux ratio R was 3, Butyl acetate and Xylene product purity were low, the R ≥ 4, the purity of the product of Xylene and Butyl acetate were significantly increased; both yield were lower with the increase of reflux ratio. When R was 4, the top temperature of the distillation column was between 109 and 111.4 °C, before and after device upgrading, Butyl acetate product purity were 90.03% and 72.88% respectively.When the top temperature was above 120 °C, the device after upgrading Xylene product purity was 98% and 94.42% before the upgrading. Both of the purity and the yield improved after device upgrading.

Abstract: This paper presents a laboratory study on active belite cement linker using mineral waste as one of the major raw meal components. The main chemical component of mineral waste employed in this study is silica (SiO₂), around 70%. The raw meals were soaked in Muffle Furnace at 1350oC for 10 minutes and 20minutes respectively, then, cooled down to room temperature using air blower. Boron Oxide was used to stabilize high temperature phases of C₂S. QXRD analysis indicates that active belite cement clinker has major mineral components consisting of Dicalcium Silicate (C₂S), Ferrite (C₂ (A_0.48F_1.52) O5) and trace amount of Tricalcium Silicate (C3S). Among them, Dicalcium silicate is over 85 percent, Ferrite around 10 percent and Tricalcium silicate less than 10 percent. Also, significant amount of high temperature polymorphic C₂S was stabilized under room temperature. Among polymorphic belite phases, α_H-C₂S accounts for around 66% of cement clinker, and αL-C₂S for about 22% of cement clinker. Scanning Eαlectronic Microscope (SEM) analysis also shows coαnsiderable round grains of C₂S. TGA-DSC spectrum indicated there is no significant phase change while cement clinker was cooling down. Also, the mechanical tests on active belite cement show that active belite cement clinker has a slow strength development at early ages, but rapid strength gain over 70Mpa at 28 days. Thus, this active belite cement clinker demonstrates very promising prospect in sustainable cement industry development.

Abstract: Coal ash belongs to a kind of mixed material like pozzolana, which is formed after the combustion of the pulverized coal at high temperature. China is the No. 1 coal production and use country all over the world, and the coal ash produced from burning coal accounts for about 30% of the total fire coal. How to use cumulative secondary resources well, reduce floor space and environmental pollution, create higher added value, and comprehensively utilization of coal ash obtains more and more attention from people. This article describes the composition nature of coal ash and comprehensive utilization status quo in construction, building materials, agriculture, environmental protection and chemical industry, and makes recommendations on the problems and development trend of coal ash in China.

Abstract: The design and operation of membrane bio-reactor (MBR) process treating hotel’s high grade gray water were introduced. The main processes were hydrolysis and acidification，MBR and disinfection, through which the removal rates of BOD₅, SS and NH₃-N were above 90%. The effluent reached the requirements of Reclamation and Reuse of Urban Sewage: Quality of Urban Service Water (GB/T18920-2002), for road irrigating, greening and toilet flushing. The hydraulic retention time of reclaimed water tank was increased to 12h, which enhanced the utilization rate of the reclaimed water to 90%. The designed wastewater amount was 360m³/d. Every year, the saving water amount is 13.14 million tons, the net income is 693800 yuan and the static payback period is 1.3 years. The project reduces pollutants and creates economic benefits.