Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education

Guangzhou, China

Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education

Guangzhou, China
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Zhang H.,South China University of Technology | Ruan X.,South China University of Technology | Hu Y.,Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education | Hu Y.,South China University of Technology | And 3 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2015

A novel adsorbent for heavy metals, chitosan/poly(vinyl alcohol) nanofiber, was prepared by electrospining and utilized for sorption of Ni(II), Cu(II) and Cd(II) ions from aqueous solutions. The prepared nanofibers were characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), X-ray diffraction (XRD) and Brunauer-Emmert-Teller (BET).The applied voltage, tip-collector distance and solution flow rate of the electrospinning process were 25 kV, 15.0 cm and 0.15 mL·h-1, respectively. The nanofiber weight ratio of chitosan:poly(vinyl alcohol) was 20∶80. Based on the results, the homogeneous electrospun nanofibers with the average diameter and surface area of 76.31 nm and 219.4 m2·g-1 were obtained respectively. The adsorption equilibrium of CS/PVA on metal ions can be reached within 2 hours. Sorption capacities of CS/PVA onto metal ions increased with the increases of temperature, initial metal ion and pH and the optimum pH was determined as 5.5. The adsorption capacities of Cu2+, Ni2+ and Cd2+ by the chitosan/poly(vinyl alcohol) nanofiber were 98.65 mg·g-1, 116.89 mg·g-1 and 124.23 mg·g-1, respectively at 25 ℃, pH 5.5 and initial heavy metal concentration of 100 mg·L-1. The sorption process was found to follow pseudo-first-order and pseudo-second-order kinetic models and the adsorption isotherm was well described by Langmuir and Freundlich adsorption isotherm models. The calculated thermodynamic parameters (ΔG, ΔH and ΔS) showed that the adsorption of metal ions onto the PVA/Chitosan nanofiber membrane was feasible, spontaneous and endothermic. ©, 2014, Science Press. All right reserved.


Nie H.,South China University of Technology | Zhu N.,South China University of Technology | Zhu N.,Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education | Yang T.,South China University of Technology | Zhang J.,South China University of Technology
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2015

Exploration of the adsorption behavior and kinetics models of leaching of copper from waste printed circuit boards by acidophilic bacteria is the basis of bioleaching mechanism. Under different initial concentrations of A. ferrooxidans, the adsorption behavior of copper leaching from circuit boards by A. ferrooxidans was investigated, the adsorption of Acidithiobacillus ferrooxidans (A. ferrooxidans) onto the surface of circuit boards was estimated and the kinetic characteristics of adsorption behavior was analyzed. The results indicated that the adsorption equilibrium of A. ferrooxidans onto the surface of circuit boards was reached in 5 h. The adsorption rates and attached biomass increased with the increase of the initial concentration of bacteria. With the initial concentrations of 2.4×105, 2.4×107 and 2. 4×109 cells·mL-1, the individual maximum sorption capacity were 1.8701, 2.3552 and 2.9833 mg·g-1, the percentage of adsorbed biomass of the total reached 43.75%, 53.97% and 55.94%, and the leaching efficiency of copper achieved 71.20%, 88.33% and 95.05%, respectively. Further analysis of nonlinear fitting proved that the pseudo-first order kinetic model was suitable for the description of adsorption behavior between A. ferrooxidans and circuit boards and R-Squared were 0.9321, 0.9134 and 0.9193, respectively. ©, 2015, Science Press. All right reserved.


Chang H.,South China University of Technology | Yi X.,South China University of Technology | Yi X.,Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education | Wei C.,South China University of Technology | Wei C.,Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education
Chinese Journal of Environmental Engineering | Year: 2016

The simple and rapid fabrication of heavy metal adsorbent with a high adsorption capacity is in growing demand. Here, we reported a one-step hydrothermal fabrication of FeOOH using ferric iron compounds as the precursors, and then investigated its application for the adsorption of Cu, Fe, Zn, and Mn, elements available while mining wastewater. Experimental results showed that the total amount of heavy metals removed by the FeOOH adsorbent was 41.67 mg·g-1 at a dosage of 0.4 g·L-1 and pH of 1.50. The specific contents adsorbed corresponding to Cu, Fe, Zn, and Mn were 6.17, 19.55, 2.22, and 2.53 mg·g-1, respectively. In comparison to adsorbents such as carboxymethyl cellulose and activated carbon, FeOOH exhibited a larger adsorption capacity at low pH. This suggests that FeOOH is appropriate for the adsorption of heavy metals in mining wastewater, without adjusting the pH with alkali. © 2016, Science Press. All right reserved.


Yang C.,South China University of Technology | Zhu N.,South China University of Technology | Zhu N.,Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education | Zhu N.,Key Laboratory of Environmental Protection and Eco Remediation of Guangdong Regular Higher Education Institutions | And 4 more authors.
Chinese Journal of Environmental Engineering | Year: 2015

Extracellular polymeric substances (EPS) play an important role in the bioleaching process. The aim of this research is to study the role of EPS in the bioleaching process of metal concentrates of waste printed circuit boards (PCBs). Then the dialysis bag experiment and bioleaching with synthetic EPS experiment were designed. The result of dialysis bag experiment indicated that the bioleaching efficiency of copper without dialysis bag was 81.4%. While the dialysis bag which prevented the contact between the cells and metal concentrates of waste PCBs was 47.9% after 7 d. The bioleaching group that the dialysis bag was removed after 2 d increased dramaticly and was 77.9% after 7 d bioleaching. It demonstrated that the concact between bacteria and metal concentrates of waste PCBs was of great importance to the bioleaching process. The synthetic EPS was utilized to explore the influence of bioleaching metal concentrates of waste PCBs. The result showed that the copper leaching efficiency of bioleaching with synthetic EPS was 92.2% while the bioleaching without synthetic EPS was 85.5%. Scanning electron microscope (SEM)also verified the difference from the surface of metal concentrates of waste PCBs. Therefore, EPS enhanced the bioleaching process of metal concentrates of waste PCBs by Acidithiobacillus ferrooxidans. ©, 2015, Science Press. All right reserved.

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