Washing Of Polychlorinated-Biphenyl From Soil By Hydroxypropyl-β-Cyclodextrin

PCBs as an important organic pollutant belonging to POPs, and is also one kind ofEDCs. Its environmental problem has became focus concerned by government,supervisor,academe and public. So, research on how to remove PCBs from soil hasgreat significance.According to basic theory of statistical analysis, an environmental friendlyreagent-HPCD was selected in the thesis, through batch-washing and column-washingexperiment, remediation of PCBs contaminated soils by HPCD was studied in thethesis, and contrast of HPCD washing and SDS washing was also evaluated accordingto the research results.The batch-experiment results of HPCD eluting showed that: the elute effect isinfluenced by such factors as concentration of HPCD, organic compound content in thesoil, volume of elute solution, elute temperature, elute way and elute number. Theelution efficiency of 50g/L HPCD is 58.2 %, 42.8%more than the 10g/L HPCD; Theelution efficiency of 60mL HPCD is 18.9% more than the 10mL HPCD; after fifthrepeated washing, The elution efficiency of 50g/L HPCD could become to 80.5% ,increased 22.3% compared to the first washing; Also, increasing temperature andtaking ultrasonic surge can increase eluting effect, the elute percentage increased by8.1% and 11.1% respectively; while increasing organic compound content woulddecrease the eluting effect; Further more, the desorption of PCBs from soils andadsorption of HPCD on the soil are studied, the desorption rate of granular soil issooner than the powdery soil, and HPCD would adsorbed on the natural polluted soil,concentration of HPCD declined rapidly in fifteen minutes, 10g/L HPCD became4.82g/L, while 5g/L HPCD became 2.99g/L.The column-experiment results of HPCDeluting showed that: the elute efficiency got increased as the increase of HPCDconcentration; the elute efficiency of distilled-water,5g/L HPCD and 10g/L HPCD is0.62%,8.42%,18.3%.The contrast of eluting effect of HPCD and SDS showed that: the elutionefficiency of 5g/LHPCD in the batch-washing and column-washing experiment is 10%and 8.42% respectively, while 10g/L HPCD is 15.4 % and 18.3% respectively; But asto 5g/L SDS solution, the elution efficiency of batch-washing and column-washing is4.3% and 2.93% respectively, while 10g/LSDS is 52% and 25.9% respectively. To obtain the same elute efficiency, the needed concentration of HPCD was greaterthan that of SDS solution. But the adsorption of SDS on the soil appeared so seriousthat it limited the elution effect. While the column eluting efficiency of HPCD hasnearly the same value as the batch eluting. HPCD is an effective reagent applying inPCBs polluted soil.