Research On Remediation Of Dichlorobenzene Contaminated Soil

With the upgrading of China’s industrial structure and adjustment of urban layout, many polluters moved out of city and the abandoned industrial contaminated sites posed a serious threat to the surrounding environments and human health. Many contaminated sites are faced with the secondary development and need to remediation urgently. The remediation effects of dichlorobenzenes contaminated sites by photocatalytic technology, phytoremediation and chemical leaching technology were studied in this research, which would provide scientific basis and technical guidance for the remediation of the dichlorobenzenes contaminated sites. The results are summarized as follows:(1)This paper studied the soil borne DCB photodegradation under the natural light and UV irradiation with o-DCB and p-DCB as target contaminants. The effects of different photosensitizer (TiO2, Fe2O3and humic acid)) and light sources (natural light and UV light) on the DCB photodegradation were investigated. The TiO2, Fe2O3and humic acid played a sensitivizing roles during the DCB photodegradation and were in line with first-order kinetics under natural light and UV light. The rate of photodegradation increased with the increasing of TiO2and Fe2O3and with the increasing of the humic acid amount at first and lowered later. The residual rate of DCB in the soil reached the lowest when the concentration of TiO2and Fe2O3were4%.The residual rate of DCB under UV light was significantly lower than under he natural light. When the HA concentration was40mg·kg-1, HA could eff-iciently sensitivize the DCB photodegrada-tion.(2)The paper studied the effect of different o-DCB pollution concentration of soil.by ryegrass pot experiment with60d.It had found that ryegrass in the low concentration (410mg kg-1and210mg kg-1) grew well in the o-DCB contaminated soil, which was died in the high pollution soil(810mg kg-1).It was illustrated that the phytoremediation technology had some limitations in the repair of heavy pollution sites.In the degradation test of410mg kg-1concentration of o-DCB,we found that the non-biological played the most important role in the degradation of o-DCB. Planting ryegrass could increase the degradation rate of o-DCB and the contribution rate of microorganisms. Planting ryegrass could also improve the activity of polyphenol oxidase in the soil. Phytoremediation technology had a broad prospect in repairing low concentration of o-DCB pollution contaminated soil.(3)The paper studied the leaching effect of different surfactants on dichlorobenzene by soil column leaching experiment. It showed that the surfactants can effectively remove DCB in soil. Non-ionic surfactant TX-100had better leaching effect than the anionic surfactant SDSand the biosurfactant(β-cyclodextrin and humic acid) on the contaminated soil and had different laws.The rate leaching of non-ionic surfacta-nt and biosur-factant increased with the increasing of concentration. Anionic surfactant to soil leaching effect of dichlorobenzene had no obvious regularity. Biosurfactants(β-cyclodextrin and humic acid) could also effectively remove DCB from contaminated soil by the leaching, which could reach to80%.Biosurfactant as environmental-friendly had its unique advantages in the field of soil remediation.