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Xiang Y.,South China University of Technology | Xiang Y.,The Key Laboratory of Pollution Control and Ecosystem Restoration | Wu P.,South China University of Technology | Wu P.,The Key Laboratory of Pollution Control and Ecosystem Restoration | And 13 more authors.
Journal of Hazardous Materials | Year: 2010

The objectives of this study were to evaluate the solubility of copper in waste printed circuit boards (PCBs) by bacterial consortium enriched from natural acid mine drainage, and to determine optimum conditions of bioleaching copper from PCBs. The results indicated that the extraction of copper was mainly accomplished indirectly through oxidation by ferric ions generated from ferrous ion oxidation bacteria. The initial pH and Fe2+ concentration played an important role in copper extraction and precipitate formation. The leaching rate of copper was generally higher at lower PCB powder dosage. Moreover, a two-step process was extremely necessary for bacterial growth and obtaining an appropriate Fe2+ oxidation rate; a suitable time when 6.25g/L of Fe2+ remained in the solution was suggested for adding PCB powder. The maximum leaching rate of copper was achieved 95% after 5 days under the conditions of initial pH 1.5, 9g/L of initial Fe2+, and 20g/L of PCB powder. All findings demonstrated that copper could be efficiently solubilized from waste PCBs by using bacterial consortium, and the leaching period was shortened remarkably from about 12 days to 5 days. © 2010 Elsevier B.V.


Yang Y.,Fujian Agriculture and forestry University | Huang S.,Guangdong Regular Higher Education Institutions | Huang S.,South China University of Technology | Zhang Y.,Guangdong Regular Higher Education Institutions | Xu F.,Guangdong Regular Higher Education Institutions
Applied Biochemistry and Biotechnology | Year: 2014

Chelatococcus daeguensis TAD1 was demonstrated to be an aerobic denitrifier. It can utilize not only nitrate and nitrite but also ammonium at high temperature (about 50 C). The strain had the capability to remove 122.7 and 71.7 mg L-1 NH4 +-N by 18 h at 50 and 30 C, respectively. Triplicate heterotrophic nitrification experiments showed that 32.3 % of removed NH4 +-N was completely converted to nitrogen gas by 18 h at 50 C. The denitrification genes involved in C. daeguensis TAD1 were identified and sequenced. It was found that the genes responsible for denitrification in TAD1 were napA, nirK, cnorB, and nosZ. Taken together, TAD1 can be an effective candidate for simultaneous nitrification and denitrificaton at high temperature. © 2013 Springer Science+Business Media New York.


Yang Y.,Fujian Agriculture and forestry University | Huang S.,Guangdong Regular Higher Education Institutions | Huang S.,South China University of Technology
Research Journal of Biotechnology | Year: 2014

Pure cultures of Chelatococcus daeguensis TAD1 were incubated at high temperature (50°C) using nitrate as a substrate and an electron acceptor for denitrification. The periplasmic nitrate reductase gene (napA), nitrite reductase gene (nirK), nitric oxide reductase gene (cnorB) and nitrous oxide reductase gene (nosZ) expression were measured using a quantitative reverse transcription-PCR at various initial dissolved oxygen (DO) concentrations. All the four genes expression reached a maximum at 12h. The maximum expression level of napA, nirK and nosZ was at 50rpm, the corresponding DO concentrations of which were 2.2 mg/l, but the maximum expression level of cnorB was at 150rpm, the corresponding DO concentrations of which were 2.6 mg/l. These results demonstrated that low dissolved oxygen conditions were more beneficial to expression of the denitrification genes in C. daeguensis TAD1 at high temperature.


Liang K.-M.,South China Agricultural University | Liang K.-M.,Key Laboratory of Agro Environment in the Tropics | Zhang J.-E.,South China Agricultural University | Zhang J.-E.,Key Laboratory of Agro Environment in the Tropics | And 7 more authors.
Chinese Journal of Ecology | Year: 2013

A laboratory experiment was conducted to study the effects of mechanical stimulation on the physiological characters of rice plant. Mechanical stimulation decreased the permeability of rice leaf plasma membrane, but, with the increase of stimulation intensity and treatment time, the permeability presented an increasing trend. The leaf chlorophyll a (Chl-a) content was increased by mechanical stimulation treatments, while the leaf chlorophyll b (Chl-b) content presented a decreasing trend. Low intensity mechanical stimulation increased the activities of protective enzymes peroxidase (POD), superoxide dismutase (SOD), and polyphenol oxidase (PPO) in rice leaves. In mechanical stimulation treatments, the leaf 3-indoleacetic acid (IAA) content was reduced with time, whereas the leaf abscisic acid (ABA) content and the root activity showed an opposite trend. These results indicated that mechanical stimulation could be one of the important reasons leading to the morphological and physiological variations of rice plant. The findings from this study could provide a theoretical basis to further study the effects and action mechanisms of mechanical stimulation on the rice plant growth in rice-duck farming system.


Jian Z.,South China University of Technology | Jian Z.,Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control | Huang S.,South China University of Technology | Huang S.,Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control | And 3 more authors.
International Journal of Photoenergy | Year: 2013

Na2Ti6O13/TiO2 composite particles were synthesized through the hydrolyzation of tetrabutyl titanate in a reverse microemulsion and characterized by thermogravimetry and differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope (SEM). The photocatalytic property of Na2Ti 6O13/TiO2 was evaluated by degradation of 2,4-dichlorophenol(2,4-DCP) under 40 W ultraviolet lamp ( = 365 nm) irradiation and compared with commercial P25-TiO2 in the same condition. The results showed that the synthesized nanobelts Na2Ti6O 13/TiO2 heterostructures had typical width from 80 to 100 nm, with thickness less than 40 nm and length up to 5 m. Such Na 2Ti6O13/TiO2 nanosized particles exhibited better photocatalytic activity than that of P25-TiO2, and the degradation rate of 2,4-DCP with initial concentration of 0.02 g/L reached 99.4% at the end of 50 min. © 2013 Zicong Jian et al.


Li B.,South China University of Technology | Li B.,Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters | Wu P.,South China University of Technology | Wu P.,Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters | And 5 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

Four kinds of layered double hydroxides (LDHs) were prepared by chemical coprecipitation method and used as DNA adsorbents. Multiple characterization tools such as power X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Standard electronic modules (SEM) were employed to characterize the LDHs. By examining the effect of initial concentration, solution pH, adsorption experiments were carried out to investigate the adsorption capacities of LDHs for DNA. The results revealed that the LDHs with Mg/Al = 3 had higher ability on adsorbing the DNA and were not affected by pH values. The LDHs exhibited excellent adsorption properties and completely adsorbed DNA within 2 h. The adsorption equilibrium data were fitted to the Langmuir and Freundlich models, showing that the Langmuir model which represented monolayer adsorption had better correlation with the adsorption linear equation. In addition, Circular dichroism (CD) spectrum, UV-vis spectorscopy and agarose gel electrophoresis revealed the integrity of DNA structure, suggesting that there had no damage on the DNA structure during the adsorption process. © 2013 Elsevier B.V. All rights reserved.


Wang R.-L.,South China Agricultural University | Wang R.-L.,Key Laboratory of Tropical Agro Environment | Wang R.-L.,Guangdong Regular Higher Education Institutions | Chen Y.,South China Agricultural University | And 20 more authors.
Chinese Journal of Ecology | Year: 2013

Mikania micrantha H. B. K. is an important invasive alien plant in South China. In this study, a virus named Mikania micrantha wilt virus (MMWV) was isolated from the invasive plant in the field, and a greenhouse experiment was conducted to inoculate the virus on 27 plant species of 9 families. A total of 12 plant species belonging to 6 families were infected. The electron microscopy observation revealed that the MMWV particle was spherical, with a diameter of about 30 nm. The MMWV could be transmitted by Myzus persicae in a non-persistent manner. Thirty days after infection by MMWV, the shoot height and the fresh weights of leaves, stems, and roots of M. micrantha were reduced significantly by 75.3%, 91.6%, 79.5%, and 75.6%, respectively, as compared to the control. The infected M. micrantha plants showed wilt, crimpled, and malformed symptoms under field conditions. Under both laboratory and field conditions, the MMWV inhibited the growth of M. micrantha efficiently. The feasibility of using the MMWV to control the invasion of M. micrantha would be worthy to be explored further.


Huang Z.,South China University of Technology | Huang Z.,Guangdong Regular Higher Education Institutions | Huang Z.,Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters | Wu P.,South China University of Technology | And 8 more authors.
RSC Advances | Year: 2014

A series of La and Ce doped hydroxyl FeAl intercalated montmorillonite (FeAl-Mt) were prepared by a co-intercalation method for catalytic oxidation of Reactive Blue 19 (RB19) by a heterogeneous photo Fenton process under natural sunlight irradiation. The physicochemical properties of the obtained catalysts were deciphered by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS) and UV-vis diffuse reflectance spectroscopy (DRS). The results showed that Ce or La doped FeAl Keggin polyoxocations were intercalated into the gallery of montmorillonite and the physicochemical properties of intercalated FeAl Keggin polyoxocations were mildly changed after Ce or La doping, resulting in defects and lattice vacancies. The doping of Ce or La could effectively improve the catalytic performance of FeAl-Mt measured by heterogeneous photo Fenton degradation of RB19 catalyzed by the obtained products. The synergistic effect between the doped element and FeAl intercalated montmorillonite played a crucial role in the enhancement of heterogeneous catalytic activity under natural sunlight irradiation. © 2014 The Royal Society of Chemistry.


Yi Z.C.,South China Agricultural University | Yi Z.C.,Guangdong Regular Higher Education Institutions | Luo S.M.,South China Agricultural University | Luo S.M.,Guangdong Regular Higher Education Institutions | And 6 more authors.
Advanced Materials Research | Year: 2013

The adsorption characteristics of Cr(VI) on activated carbon prepared from several agriculture by-products via sulphuric acid-treatment were compared and the best concentration of sulphuric acid for carbonization were evaluated. It is confirmed that peanut shell is best material for the absorption of Cr(VI) ion from aqueous solution among hybrid giant napier straw, rice husk and commercial activated carbon in this study. The effects of agitation time, solution pH, temperature and Cr(VI) initial concentration on Cr(VI) adsorption were investigated. The 3:1 volume ratio of sulphuric acid: deionized water is the optimal concentration for Cr(VI) biosorption for peanut shell carbonization. Cr(VI) adsorption is highly dependent on solution pH. Initial solution pH =1.5 was the most favorable pH for Cr(VI) removal. Cr(VI) biosorption increases with increasing initial concentration, agitation time and solution temperature. The adsorption kinetics is found well fitted to the pseudo-second-order kinetic model. The adsorption equilibrium data are best represented by Langmuir model.The maximum adsorption capacity of carbonized peanut shell for Cr(VI) reached 26.22 mg/g. © (2013) Trans Tech Publications, Switzerland.

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