Sep 2009, Volume 3 Issue 3
    

  • Select all
  • Research articles
    Nanomaterials for environmental burden reduction, waste treatment, and nonpoint source pollution control: a review
    Guobin SHAN , Rajeshwar D. TYAGI , Rao Y. SURAMPALLI , Tian C. ZHANG
    2009, 3(3): 249-264. https://doi.org/10.1007/s11783-009-0029-0
    Download PDF
    Nanomaterials are applicable in the areas of reduction of environmental burden, reduction/treatment of industrial and agricultural wastes, and nonpoint source (NPS) pollution control. First, environmental burden reduction involves green process and engineering, emissions control, desulfurization/denitrification of nonrenewable energy sources, and improvement of agriculture and food systems. Second, reduction/treatment of industrial and agricultural wastes involves converting wastes into products, groundwater remediation, adsorption, delaying photocatalysis, and nanomembranes. Third, NPS pollution control involves controlling water pollution. Nanomaterials alter physical properties on a nanoscale due to their high specific surface area to volume ratio. They are used as catalysts, adsorbents, membranes, and additives to increase activity and capability due to their high specific surface areas and nano-sized effects. Thus, nanomaterials are more effective at treating environmental wastes because they reduce the amount of material needed.
  • Research articles
    Complete oxidation of methane on CoO-SnO catalysts
    Xingfu TANG , Jiming HAO , Junhua LI ,
    2009, 3(3): 265-270. https://doi.org/10.1007/s11783-009-0019-2
    Download PDF
    Co3O4-SnO2 hybrid oxides were prepared by the coprecipitation method and were used to oxidate methane (CH4) in presence of oxygen. The Co3O4-SnO2 with a molar ratio of Co/(Co+Sn) at 0.75 exhibited the highest catalytic activity among all the Co3O4-SnO2 hybrid oxides. Experimental results showed that the catalysts were considerably stable in the CH4 combustion reaction, and were verified by X-ray photoelectron spectra (XPS). It was found that Co3O4 was the active species, and SnO2 acted as a support or a promoting component in the Co3O4-SnO2 hybrid oxides. The surface area was not a major factor that affected catalytic activity. The hydrogen temperature-programmed reduction (H2-TPR) results demonstrated that the interaction between cobalt and tin oxides accelerated the mobility of oxygen species of Co3O4-SnO2, leading to higher catalytic activity.
  • Research articles
    Photocatalytic degradation of methyl orange using ZnO/TiO composites
    Ming GE , Changsheng GUO , Xingwang ZHU , Lili MA , Wei HU , Yuqiu WANG , Zhenan HAN ,
    2009, 3(3): 271-280. https://doi.org/10.1007/s11783-009-0035-2
    Download PDF
    ZnO/TiO2 composites were synthesized by using the solvothermal method and ultrasonic precipitation followed by heat treatment in order to investigate their photocatalytic degradation of methyl orange (MO) in aqueous suspension under UV irradiation. The composition and surface structure of the catalyst were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and transmission electron microscopy (TEM). The degradation efficiencies of MO at various pH values were obtained. The highest degradation efficiencies were obtained before 30min and after 60min at pH 11.0 and pH 2.0, respectively. A sample analysis was conducted using liquid chromatography coupled with electrospray ionization ion-trap mass spectrometry. Six intermediates were found during the photocatalytic degradation process of quinonoid MO. The degradation pathway of quinonoid MO was also proposed.
  • Research articles
    Catalytic decomposition of low level ozone with gold nanoparticles supported on activated carbon
    Pengyi ZHANG , Bo ZHANG , Rui SHI ,
    2009, 3(3): 281-288. https://doi.org/10.1007/s11783-009-0032-5
    Download PDF
    Highly dispersed gold nanoparticles were supported on coal-based activated carbon (AC) by a sol immobilization method and were used to investigate their catalytic activity for low-level ozone decomposition at ambient temperature. Nitrogen adsorption-desorption, scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the catalysts before and after ozone decomposition. The results showed that the supported gold nanoparticles prepared with microwave heating were much smaller and more uniformly dispersed on the activated carbon than those prepared with traditional conduction heating, exhibiting higher catalytic activity for ozone decomposition. The pH values of gold precursor solution significantly influenced the catalytic activity of supported gold for ozone decomposition, and the best pH value was 8. In the case of space velocity of 120000h−1, inlet ozone concentration of 50mg/m3, and relative humidity of 45%, the Au/AC catalyst maintained the ozone removal ratio at 90.7% after 2500min. After being used for ozone decomposition, the surface carbon of the catalyst was partly oxidized and the oxygen content increased accordingly, while its specific surface area and pore volume only decreased a little. Ozone was mainly catalytically decomposed by the gold nanoparticles supported on the activated carbon.
  • Research articles
    Photocatalytic activity of ZnO films with micro-grid structure
    Chunzhi LI , Wenwen WANG , Junying ZHANG , Hailing ZHU , Weiwei ZHANG , Tianmin WANG ,
    2009, 3(3): 289-293. https://doi.org/10.1007/s11783-009-0034-3
    Download PDF
    A layer of zinc oxide (ZnO) micro-grid was deposited on the surface of ZnO film using the DC reactive magnetron sputtering method and the micro-sphere lithography technique on glass substrates. Samples of this layer were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and ultraviolet-visible light spectroscopy. X-ray diffraction showed the high crystallinity of ZnO film and the regular arrangement of the micro-grid. The micro-grid ZnO has a lower specular reflection and a higher diffuse reflection, allowing incident light to reflect two or three times to enhance the usage of light. Photocatalytic degradation experiments on methylene blue using both ZnO micro-grid and ordinary film showed that the ZnO micro-grid has better photocatalytic properties than ordinary film. The ZnO micro-grid enhanced the photocatalytic efficiency of ZnO film by 28% with a degradation time of 300min.
  • Research articles
    Noncovalent immobilization of MnP from on carbon nanotubes
    Jiaxi LI , Xianghua WEN ,
    2009, 3(3): 294-299. https://doi.org/10.1007/s11783-009-0041-4
    Download PDF
    Manganese peroxidases (MnP) from Phanerochaete chrysosporium were adsorbed onto multi-walled carbon nanotubes (MWNT). Four different loadings of MnP on MWNTs were investigated, and the maximum enzyme loading of 47.5 µg/mg of MWNTs was obtained in 12 h. The adsorbed MnP showed a catalytic activity of up to 0.1 U/mg of the weight of the system of MnP/MWNTs, with 23% of its original activity retained. The AFM image of the adsorbed enzymes indicated that a layer of MnP covered the surface of the MWNTs and retained its original three-dimensional shape. Amino-based nonspecific interactions may play the dominant role in the adsorption of MnP on MWNTs.
  • Research articles
    Thermochemical pretreatment of meat and bone meal and its effect on methane production
    Guangxue WU , Zhenhu HU , Mark G. HEALY , Xinmin ZHAN ,
    2009, 3(3): 300-306. https://doi.org/10.1007/s11783-009-0031-6
    Download PDF
    Since the solubilization of meat and bone meal (MBM) is a prerequisite in many MBM disposal approaches, enhancement of the solubilization by means of thermochemical pretreatment was investigated in this study at two temperatures (55°C and 131°C) and six sodium hydroxide (NaOH) concentrations (0, 1.25, 2.5, 5, 10 and 20g/L). The MBM volatile solid (VS) reduction ratio was up to 66% and 70% at 55°C and 131°C, respectively. At the same temperature, the VS reduction ratio increased with the increase in the dosage of NaOH. The study on the methane (CH4) production potential of pretreated MBM shows that the addition of NaOH at 55°C did not cause the inhibition of the succeeding CH4 production process. However, CH4 production was inhibited by the addition of NaOH at 131°C. The CH4 production potential was in the range of 389 to 503mL CH4/g VS MBM and 464 to 555mL CH4/g VS MBM at 55°C and 131°C, respectively.
  • Research articles
    A mini-microbial fuel cell for voltage testing of exoelectrogenic bacteria
    Xiaoxin CAO , Xia HUANG , Xiaoyuan ZHANG , Peng LIANG , Mingzhi FAN ,
    2009, 3(3): 307-312. https://doi.org/10.1007/s11783-009-0028-1
    Download PDF
    Abstract Current methods for testing the electricity generation capacity of isolates are time- and labor-consuming. This paper presents a rapid voltage testing system of exoelectrogenic bacteria called Quickscreen, which is based on a microliter microbial fuel cell (MFC). Geobacter sulfurreducens and Shewanella baltica were used as the model exoelectrogenic bacteria; Escherichia coli that cannot generate electricity was used as a negative control. It was found that the electricity generation capacity of the isolates could be determined within about five hours by using Quickscreen, and that its time was relatively rapid compared with the time needed by using larger MFCs. A parallel, stable, and low background voltage was achieved using titanium as a current collector in the blank run. The external resistance had little impact on the blank run during the initial period. The cathode with a five-hole configuration, used to hydrate the carbon cathode, gave higher cathode potentials than did that with a one-hole configuration. Steady discharge and current interrupt methods showed that the anode mostly contributed to the large internal resistance of the Quickscreen system. However, the addition of graphite felt decreased the resistance from 18kΩ to 5kΩ. This device was proved to be useful to rapidly evaluate the electricity generation capacity of different bacteria.
  • Research articles
    Modified landfill gas generation rate model of first-order kinetics and two-stage reaction
    Jiajun CHEN , Hao WANG , Na ZHANG ,
    2009, 3(3): 313-319. https://doi.org/10.1007/s11783-009-0025-4
    Download PDF
    This investigation was carried out to establish a new domestic landfill gas (LFG) generation rate model that takes into account the impact of leachate recirculation. The first-order kinetics and two-stage reaction (FKTSR) model of the LFG generation rate includes mechanisms of the nutrient balance for biochemical reaction in two main stages. In this study, the FKTSR model was modified by the introduction of the outflow function and the organic acid conversion coefficient in order to represent the in-situ condition of nutrient loss through leachate. Laboratory experiments were carried out to simulate the impact of leachate recirculation and verify the modified FKTSR model. The model calibration was then calculated by using the experimental data. The results suggested that the new model was in line with the experimental data. The main parameters of the modified FKTSR model, including the LFG production potential (L0), the reaction rate constant in the first stage (K1), and the reaction rate constant in the second stage (K2) of 64.746 L, 0.202 d−1, and 0.338 d−1, respectively, were comparable to the old ones of 42.069 L, 0.231 d−1, and 0.231 d−1. The new model is better able to explain the mechanisms involved in LFG generation.
  • Research articles
    Comparison between linear and non-linear forms of pseudo-first-order and pseudo-second-order adsorption kinetic models for the removal of methylene blue by activated carbon
    Junxiong LIN , Lan WANG ,
    2009, 3(3): 320-324. https://doi.org/10.1007/s11783-009-0030-7
    Download PDF
    The best-fit equations of linear and non-linear forms of the two widely used kinetic models, namely pseudo-first-order and pseudo-second-order equations, were compared in this study. The experimental kinetics of methylene blue adsorption on activated carbon was used for this research. Both the correlation coefficient (R2) and the normalized standard deviation Δq(%) were employed as error analysis methods to determine the best-fitting equations. The results show that the non-linear forms of pseudo-first-order and pseudo-second-order models were more suitable than the linear forms for fitting the experimental data. The experimental kinetics may have been distorted by linearization of the linear kinetic equations, and thus, the non-linear forms of kinetic equations should be primarily used to obtain the adsorption parameters. In addition, the Δq(%) method for error analysis may be better to determine the best-fitting model in this case.
  • Research articles
    Relationship between heavy metal concentrations of herbaceous plants and soils at four Pb-Zn mining sites in Yunnan, China
    Yuan LI , Yanqun ZU , Qixian FANG , Zhaohua GAO , Christian SCHVARTZ ,
    2009, 3(3): 325-333. https://doi.org/10.1007/s11783-009-0024-5
    Download PDF
    This paper studied the relationship between heavy metal concentrations of herbaceous plants and soils at four Pb-Zn mining sites in Yunnan, China. 50 herbaceous plant samples of 9 plant species from 4 families and 50 soil samples were collected and then ana1yzed for the tota1 concentrations of Pb, Cd, and Zn. The results showed that the average concentrations of Pb, Cd, and Zn in soil samples were 3772.83, 168.81, and 5385.65 mg/kg, respectively. The average concentrations of Pb, Cd, and Zn were 395.68, 28.14, and 1664.20 mg/kg in the shoots, and 924.12, 57.25 , and 1778.75 mg/kg in the roots, respectively. Heterospecific plants at the same site and conspecific plants at various sites had different average levels of Pb, Cd, and Zn, both in the shoots and the roots. Enrichment coefficients of Pb, Cd, and Zn were greater than 1 in 2, 3, and 9 herbaceous plant samples, respectively. Translocation factors of Pb, Cd, and Zn were greater than 1 in 10, 17, and 25 herbaceous plant samples, respectively. In all 50 samples, the concentrations of Pb, Cd, and Zn between the shoots and the roots, the shoots, and the soils, and the roots and the soils had significant positive relationships.
  • Research articles
    Seasonal variation of nitrogen and phosphorus in Xiaojiang River—A tributary of the Three Gorges Reservoir
    Zhe LI , Jinsong GUO , Man LONG , Fang FANG , Jinping SHENG , Hong ZHOU ,
    2009, 3(3): 334-340. https://doi.org/10.1007/s11783-009-0039-y
    Download PDF
    A yearlong monitoring program in the backwater area of Xiaojiang River (XBA) was launched in order to investigate the eutrophication of backwater areas in tributaries of the Yangtze River in the Three Gorges Reservoir (TGR) in China, starting after the impoundment water level of the TGR reached 156 m. From March 2007 to March 2008, the average concentration of total nitrogen (TN) and total phosphorus (TP) were (1553 ± 484) μg·L−1 and (62 ± 31) μg·L−1, respectively. The mean value of chlorophyll was (9.07 ± 0.91) μg·L−1. The trophic level of XBA was meso-eutrophic, while the general nutrient limitation was phosphorus. The results indicated that XBA has a strong ability to purify itself and has non-point source pollution from terrestrial runoff. The variation of TN/TP ratio was caused by a variation in TN rather than in TP when TN/TP<22. N-fixation from cyanobacteria occurred and became an important process in overcoming the nitrogen deficit under a low TN/TP ratio. When TN/TP ≥ 22, the variation of TP affected the TN/TP ratio more significantly than TN. The increase of TP in XBA was caused mainly by particulate phosphorus, which could originate from a non-point source as adsorptive inorganic forms after heavy rainfall and surface runoff. An increase in the river’s flow could also contribute to an unstable environment for the growth of phytoplankton.
  • Research articles
    Appraisal of coastal recreational resources in Qingdao by travel cost method
    Jingmei LI , Tieying LIU , Yuanyuan ZHANG , Lei LI ,
    2009, 3(3): 341-347. https://doi.org/10.1007/s11783-009-0038-z
    Download PDF
    This paper serves to appraise the monetary cost of coastal recreational resources in Qingdao using the travel cost method (TCM), which is typically used in developed countries. The total revenue produced by Qingdao’s coastal recreational resources is about RMB 5.51×1010 annually, based on questionnaires given at Qingdao’s major tourist destinations. These questionnaires establish correlation functions that factor in the number of tourists, travel expenses, etc. The data processing software named Eviews was used to determine the tourist demand regression curve and to calculate their residual and actual travel expenses. The results of this study can provide a scientific basis for applicable industries interested in development and management decision-making. Therefore, this study assesses the reasonable usage of coastal recreational resources.
  • Research articles
    Field test of best management practice pollutant removal efficiencies in Shenzhen, China
    Ru ZHANG , Wenbin ZHOU , Richard FIELD , Anthony TAFURI , Shaw L. YU , Keli JIN ,
    2009, 3(3): 354-363. https://doi.org/10.1007/s11783-009-0033-4
    Download PDF
    This paper presents a study on the use of best management practices (BMPs) for controlling nonpoint pollution in the Xikeng Reservoir watershed located in Shenzhen, China. A BMP treatment train design, including a pond, a wetland, and a buffer strip placed in series was implemented at the reservoir location. A separate grass swale was also constructed at the site. Low impact development (LID) BMPs, namely a planter box and bioboxes, were used at the parking lot of the reservoir’s Administration Building. Samples were collected during storm events and were analyzed for total suspended solids (TSS), biochemical oxygen demand (BOD5), ammonia nitrogen (NH3—N), and total phosphorus (TP). The removal efficiencies of both BMP systems were evaluated using the Efficiency Ratio (ER) method based on the event mean concentration (EMC) data. In summary, the pond/wetland treatment train removed 70%―90% of TSS, 20%―50% of BOD5, and 30%―70% of TP and NH3—N. The swale removed 50%―90% of TSS, 30%―55% of BOD5, −10%―35% of NH3—N, and 25%―70% of TP. For the planter box and biobox, the ranges of removal rates were 70%―90%, 20%―50%, and 30%―70% for TSS, BOD5, and ammonia and phosphorus, respectively.
  • Research articles
    Emergency drinking water treatment in source water pollution incident-technology and practice in China
    Xiaojian ZHANG , Chao CHEN ,
    2009, 3(3): 364-368. https://doi.org/10.1007/s11783-009-0027-2
    Download PDF
    An investigation into emergency potable water treatment technologies was conducted to investigate China’s water pollution situation. In order to confirm optimum parameters, the technological efficiency of each pollutant was obtained. About 100 contaminants were tested to find the emergency treatment technologies, most of which were found to be positive. This paper presents the three largest and most significant water pollution incidents in China to date, analyzing cases such as the nitrobenzene pollution incident in the Songhua River in November 2005, the cadmium pollution incident in the Beijiang River in December 2005, and the water crisis with odorous tap water in Wuxi City in May 2007.
  • Research articles
    Effects of La, Ce on nitrogen removal in sequencing batch reactor
    Qing XIA , Rui LIANG , Yuning HONG , Lili DING , Hongqiang REN , Yuxiang MAO , Mingyu ZHAO ,
    2009, 3(3): 369-374. https://doi.org/10.1007/s11783-009-0036-1
    Download PDF
    Batch experiments were conducted to study the short-term biological effects of rare earth ions (La3+, Ce3+) and their mixture on the nitrogen removal in a sequencing batch reactor (SBR). The data showed that higher NH+4―N removal rate, total inorganic nitrogen removal efficiency, and denitrification efficiency were achieved at lower concentrations of rare earth elements (REEs) (<1mg/L). In the first hour of the aeration stage of SBR, the presence of REEs increased the total inorganic nitrogen removal efficiency and NH+4―N removal efficiency by 15.7% and 10%―15%, respectively. When the concentrations of REEs were higher than 1mg/L, the total inorganic nitrogen removal efficiency decreased, and nitrate was found to accumulate in the effluent. When the concentrations of REEs was up to 50.0mg/L, the total inorganic nitrogen removal efficiency was less than 30% of the control efficiency with a high level of nitrate. Lower concentrations of REEs were found to accelerate the nitrogen conversion and removal in SBR.