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.
Wu Y.,South China University of Technology |
Wu Y.,The Key Laboratory of Pollution Control and Ecosystem Restoration |
Luo H.,South China University of Technology |
Luo H.,The Key Laboratory of Pollution Control and Ecosystem Restoration |
And 7 more authors.
Journal of Colloid and Interface Science | Year: 2013
In this study, cetyltrimethylammonium bromide was chosen to modify graphene, which was prepared using a modified Hummers' method. The characteristics of graphene and modified graphene were characterized by X-ray diffraction, Fourier transform infrared spectrum, X-ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy. The effect factors including pH, contact time, temperature, and dosage on the adsorption properties of Cr(VI) onto graphene and modified graphene were investigated. Batch experiments were conducted to evaluate the adsorbance of Cr(VI) from aqueous solution using graphene and modified graphene as the adsorbent under different conditions. The results revealed that the optimal pH for the adsorption was about 2, and the best suitable temperature was at 293. K. The adsorption processes were rapid within the first 5. min and reached equilibrium in about 40. min. The adsorption kinetics fitted well with pseudo-second-order model. The adsorption capacity of Cr(VI) on modified graphene inferred from the Langmuir model was 21.57. mg/g at 293. K. The thermodynamic parameters indicated that the adsorption of Cr(VI) onto modified graphene was an exothermic and spontaneous process. © 2012 Elsevier Inc.
Zhu N.,South China University of Technology |
Zhu N.,The Key Laboratory of Pollution Control and Ecosystem Restoration |
Zhu N.,The Key Laboratory of Pollution Control and Eco remediation of Guangdong Provincial Higher Education |
Chen X.,South China University of Technology |
And 10 more authors.
Bioresource Technology | Year: 2011
Surface modifications of anode materials are important for enhancing power generation of microbial fuel cell (MFC). Membrane free single-chamber air-cathode MFCs, MFC-A and MFC-N, were constructed using activated carbon fiber felt (ACF) anodes treated by nitric acid and ethylenediamine (EDA), respectively. Experimental results showed that the start-up time to achieve the maximum voltages for the MFC-A and MFC-N was shortened by 45% and 51%, respectively as compared to that for MFC-AT equipped with an unmodified anode. Moreover, the power output of MFCs with modified anodes was significantly improved. In comparison with MFC-AT which had a maximum power density of 1304mW/m2, the MFC-N achieved a maximum power density of 1641mW/m2. The nitric acid-treated anode in MFC-A increased the power density by 58% reaching 2066mW/m2. XPS analysis of the treated and untreated anode materials indicated that the power enhancement was attributable to the changes of surface functional groups. © 2010 Elsevier Ltd.
Wu C.D.,South China University of Technology |
Wu C.D.,The Key Laboratory of Pollution Control and Ecosystem Restoration |
Zhang Z.L.,South China University of Technology |
Zhang Z.L.,The Key Laboratory of Pollution Control and Ecosystem Restoration |
And 4 more authors.
Desalination and Water Treatment | Year: 2015
The combination of H2O2 and hydrodynamic cavitation has been used to degrade phenol in water. The effects of parameters including inlet pressure (P1), orifice geometries of hydrodynamic reactor, initial concentration of H2O2, the presence of dissolved gases and catalysts (CuO, Fe, and TiO2) have been discussed. It revealed that increased P1, more number of holes on plates, optimum initial H2O2 concentration, the higher flow rate of oxygen, and the presence of Fe or CuO are more favorable in phenol degradation. Nitrogen has different effect on cavitation from oxygen. Furthermore, the identification of primary intermediates of the reaction (hydroquinone, catechol, benzoquinone, and resorcin) indicated that hydroxyl radicals are involved in phenol degradation mechanisms. © 2013, © 2013 Balaban Desalination Publications. All rights reserved.