| With the globalization and the growth of population, it is urgent to expand the urban areas in the urban development process. Therefore, industrial areas in suburban districts are frequently relocated for the demands of industrialization. Because of the lack of pollution management and advanced waste treatment technology, it leads to serious environmental problems and many waste materials have been discarded without proper treatment during the running process of the industrial zone. Thus, the left or abandoned industrial zone land use is an important concern. It is necessary and important to survey the environmental quality of typically polluted regions in order to restore the land for further use and improve the living environment. This PhD thesis takes two kinds of typical industial zones as the research objects and establishes a method for simultaneous determination of several organic pollutants in soil, and discusse the distribution features of pollutants in such abandoned industrial zone. Also, electrochemical remediation on certain pollutants with electricity self-generation via coupled reodx fuel cell has also been investigated.Different methods for the determination of pollutants in soils were established, including gas chromatography-mass spectrometry (GC-MS) for the determination of 18 kinds of poly brominated diphenylethers (PBDEs) and poly bromominated biphenyls (PBBs), and liquid chromatography-tandem mass spectrometry (LC-MS) for the determination of TBBPA, α-HBCD, β-HBCD and y-HBCD. The samples were extracted by accelerated solvent extraction (ASE) and cleaned up by gel permeation chromatographic technique (GPC).13C-labeled PCB and PBDE were added as internal standardand surrogate compound for quantitative determination. GC-EI/MS was used to analyze the low-brominated PBDEs and PBBs, while GC-NCI/MS was applied for the high-brominated PBDEs and PBBs, including BB-209, BB-206, BB-194 and BDE-209. Isotope dilution method was employed for the analysis of BDE-209 to obtain accurate data. Our experiments showed that the average standard addition recoveries were 43.8%-97.2% (n=22) and the relative standard deviations were 18%-31%. The limit of detection (LOD) of all compounds was 0.15-0.43 μg/kg, and LOD of BDE-209 was 4.0 μg/kg. An electrospray ionization tandem mass spectrometry in the multiple-reaction-monitoring negative mode was used to detect TBBPA and HBCD. The quantitative results were calculated by the internal standard methods. The results showed that the limits of detection (LODs) of TBBPA, α-HBCD,β-HBCD, and y-HBCD ranged from 0.1μg/kg to 1.2 μg/kg, while the standard addition recoveries were from 81.8% to 113%, and the relative standard deviations(RSDs) were less than 10%. In addition, other analytical methods including dermination of Poly Aromatic Hydrocabons (PAHs) in soils via GC-MS and dermination of heavy metals in soils via Inductively Coupled Plasma (ICP) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) were also established for the study of soil pollution. Present methods optimize the technologies of sample pretreatment and analysis, and it can be widely applied to the detection of a large number of samples.On the basis of the establishment of analytical methods, two typical industrial zones were selected for the research of soil pollutions. Taking the typical abandoned chemical zone as the analysis object, single pollution index was employed to discuss the heavy metal pollutions (HMs) of legacy chemical district. By analyzing soils, sediments, surface water and underground water collected from the research zone, the main pollutants were quantitatively identified and spatial distribution patterns were clearly displayed. Eleven types of HMs pollutants were obtained and the results indicated a significant correlation between the industrial zone soil pollution and HMs pollutants in river sediment. The arsenic content in surface soil diffused from the center of the pollution source to the surrounding proliferation, and longitudinal distribution involved from surface to deep migration. The mean concentrations at the pollution source, in the surrounding area and in the sediment are found to be 603,20.4, and 22.5 mg/kg, respectively. Our study suggested that it is necessary to remediate the contaminated areas before it can be considered for reuse, and pollution index method could be a useful tool for assessing soils quality to provide comparable criteria.Another typical e-waste recycling area was chosen to discuss the pollution of heavy metals and characteristic organic coumpounds. A total of 39 surface soil samples were collected and analyzed for the heavy metals and brominated compounds. The results indicated that the contents of heavy metals meet the standard limits except a few sample points. The contents of Sb, Cu were twice than that of control point, while the content of Cd was ten times than that of control point. The average amounts of TBBPA, X?PBDEs and BDE-209 in surrounding soil were 2.46×10-3,1.36×10-3, 0.130 mg/kg, respectively. BDE-209 occupied the 90% of PBDEs, while other seven BDEs were less than 10%.On the basis of aboved results, coupled redox fuel cell (CRFC) combining with the reductive and oxidative contaminants was construced. The approach explores the feasibility of this promising technique without the requirement of energy input for simultaneous removal of pollutants and the generation of electricity. Two kinds of materials were selected, chromium-slags and biphenol A (BPA), which were similar to pollutants found in previous study. By using Ni/C catalyst in the anode, CRFC was constructed to generate electricity, while pollutants were simultaneously removed. This technology provides a new idea for soil remediation.CRFC of K2Cr2O7-BPA was also constructed. With the excessive BPA in the anode, maxium open circuit voltage of 0.84-0.92 V was obtained. When 88 mM BPA was used in anode, the removal efficienty of Cr(VI) was 98% with the initial Cr(VI) at 2.88 mM after 25 h process. The total quantity of electricity is 12.9 C and cathode efficienty of 91% could be achieved. Meanwhile, with the excessive Cr(VI) in the cathode, a maxium open circuit voltage of 1.05～1.08 V and a maxium power density of 78.1μW·cm-2 were obtained. When the content of Cr(VI) at cathode is 100 mM Cr(VI) at cathode, the removal rate of BPA is 34% with the initial BPA content of 4.4 mM after 36 h process of CRFR.Furthermore, chromium-slags were choosed as typical pollutants to simulate the acid rain, and dynamic leaching experiments of chromium-slag samples were conducted to survey the release and leaching behavior of Cr(VI). Different elution solution, rain amounts, elution time were considered to demonstrate the effect of dynamic leaching. Then a unique urea-Cr(VI) CRFC was designed, in which urea was employed as the fuel and Cr(VI) from leakage of dichromate slag is used as the oxidant. The electro-oxidation of urea occurs at the anode and converts into the CO2 and H2O, while Cr(VI) in the cathodic is reduced to the low toxicity Cr(Ⅲ). This method was regarded as the new remediation technology for special pollutants. When the initial content of urea is 1.0 mM and the load resistance is 985Ω, the electrochemical results showed that the removal percent of Cr(VI) was more than 96% after 18 h. The open circuit potential (OCP) varied in the range of 1.56-1.59 V under different initial Cr(VI) leakage concentration, and the maximum power dentisy of 2.52 mW·cm-2 could be obtained.In conclusion, remediation of pollutants via coupled redox fuel cell was establised with haveseting energy originated from waste material. The electrical remediation method could be a new hot spot and applied for harmless treatment of heavy metals and organic pollutant in soils. |
PDF Full Text Request