The removal efficiency of heavy metals from offshore muds is enhanced in the presence of generated chlorine gas (Cl2). The tests showed a high removal efficiency of heavy metals at the anode end of cores after 24 hour...The removal efficiency of heavy metals from offshore muds is enhanced in the presence of generated chlorine gas (Cl2). The tests showed a high removal efficiency of heavy metals at the anode end of cores after 24 hours of EK application. In the initial tests, high electrokinetic flow potential was achieved;however, high levels of chlorine gas were produced in the high-salinity environments. The process was improved by controlling and maintaining a certain fraction of the chlorine gas (Cl2) in place. The pH was controlled by the chlorine gas maintained in-situ and transported from the anode to cathode. The transports of four heavy metals were evaluated in this study. The chlorine gas can have two impacts on the transport of metals in the system. One is to oxidize the metal ions to a higher oxidation state and the second is to form chloride complexes, which have higher mobility in the system. Determination of oxidation state and the subsequent metal chloride complex are left for future research.展开更多
Removal of hydrophobic organic contaminants (HOCs) from soil of low permeability by electroremedia-tion was investigated by using phenanthrene and kaolinite as a model system. Tween 80 was added into the purging solut...Removal of hydrophobic organic contaminants (HOCs) from soil of low permeability by electroremedia-tion was investigated by using phenanthrene and kaolinite as a model system. Tween 80 was added into the purging solution in order to enhance the solubility of phenanthrene. The effects of pH on the adsorption of phenanthrene and Tween 80 on kaolinite and the magnitude of -potential of kaolinite were examined, respectively. The effects of electric field strength indicated by electric current on the electroremediation behavior, including the pH of purging solution, the conductivity, phenanthrene concentration and flow rate of effluent, were experimentally investigated, respectively. In case of an electric field of 25 mA applied for 72 hours, over 90% of phenanthrene was removed from 424 g (dry mass) of kaolinite at an energy consumption of 0.148 kW-h. The experimental results described in present study show that the addition of surfactant into purging solution greatly enhances the removal of HOCs by electroremediation.展开更多
Microbial electrochemical technologies have been extensively employed for phenol removal.Yet,previous research has yielded inconsistent results,leaving uncertainties regarding the feasibility of phenol degradation und...Microbial electrochemical technologies have been extensively employed for phenol removal.Yet,previous research has yielded inconsistent results,leaving uncertainties regarding the feasibility of phenol degradation under strictly anaerobic conditions using anodes as sole terminal electron acceptors.In this study,we employed high-performance liquid chromatography and gas chromatography-mass spectrometry to investigate the anaerobic phenol degradation pathway.Our findings provide robust evidence for the purely anaerobic degradation of phenol,as we identified benzoic acid,4-hydroxybenzoic acid,glutaric acid,and other metabolites of this pathway.Notably,no typical intermediates of the aerobic phenol degradation pathway were detected.One-chamber reactors(t0.4 V vs.SHE)exhibited a phenol removal rate of 3.5±0.2 mg L^(-1) d^(-1),while two-chamber reactors showed 3.6±0.1 and 2.6±0.9 mg L^(-1) d^(-1) at anode potentials of t0.4 and t 0.2 V,respectively.Our results also suggest that the reactor configuration certainly influenced the microbial community,presumably leading to different ratios of phenol consumers and microorganisms feeding on degradation products.展开更多
文摘The removal efficiency of heavy metals from offshore muds is enhanced in the presence of generated chlorine gas (Cl2). The tests showed a high removal efficiency of heavy metals at the anode end of cores after 24 hours of EK application. In the initial tests, high electrokinetic flow potential was achieved;however, high levels of chlorine gas were produced in the high-salinity environments. The process was improved by controlling and maintaining a certain fraction of the chlorine gas (Cl2) in place. The pH was controlled by the chlorine gas maintained in-situ and transported from the anode to cathode. The transports of four heavy metals were evaluated in this study. The chlorine gas can have two impacts on the transport of metals in the system. One is to oxidize the metal ions to a higher oxidation state and the second is to form chloride complexes, which have higher mobility in the system. Determination of oxidation state and the subsequent metal chloride complex are left for future research.
基金Supported by the National Natural Science Foundation (No. 29976020) and Tsinghua University Foundation.
文摘Removal of hydrophobic organic contaminants (HOCs) from soil of low permeability by electroremedia-tion was investigated by using phenanthrene and kaolinite as a model system. Tween 80 was added into the purging solution in order to enhance the solubility of phenanthrene. The effects of pH on the adsorption of phenanthrene and Tween 80 on kaolinite and the magnitude of -potential of kaolinite were examined, respectively. The effects of electric field strength indicated by electric current on the electroremediation behavior, including the pH of purging solution, the conductivity, phenanthrene concentration and flow rate of effluent, were experimentally investigated, respectively. In case of an electric field of 25 mA applied for 72 hours, over 90% of phenanthrene was removed from 424 g (dry mass) of kaolinite at an energy consumption of 0.148 kW-h. The experimental results described in present study show that the addition of surfactant into purging solution greatly enhances the removal of HOCs by electroremediation.
基金China Scholarship Council(CSC201804910500)for 4-year granting study abroadsupported by the Helmholtz Association in the frame of the Integration Platform“Tapping nature's potential for sustainable production and a healthy environment”at the UFZ.
文摘Microbial electrochemical technologies have been extensively employed for phenol removal.Yet,previous research has yielded inconsistent results,leaving uncertainties regarding the feasibility of phenol degradation under strictly anaerobic conditions using anodes as sole terminal electron acceptors.In this study,we employed high-performance liquid chromatography and gas chromatography-mass spectrometry to investigate the anaerobic phenol degradation pathway.Our findings provide robust evidence for the purely anaerobic degradation of phenol,as we identified benzoic acid,4-hydroxybenzoic acid,glutaric acid,and other metabolites of this pathway.Notably,no typical intermediates of the aerobic phenol degradation pathway were detected.One-chamber reactors(t0.4 V vs.SHE)exhibited a phenol removal rate of 3.5±0.2 mg L^(-1) d^(-1),while two-chamber reactors showed 3.6±0.1 and 2.6±0.9 mg L^(-1) d^(-1) at anode potentials of t0.4 and t 0.2 V,respectively.Our results also suggest that the reactor configuration certainly influenced the microbial community,presumably leading to different ratios of phenol consumers and microorganisms feeding on degradation products.
