Electrokinetic Transport Of Carboxymethyl Cellulose Stabilized Pd/Fe Nanoparticles For The Remediation Of Pentachlorophenol-contaminated Soil

As a well-known organochlorine compound mainly used as a general herbicide, pesticide and wood preservative, as well as an insecticide and broad-spectrum pentachlorophenol (PCP) has caused a serious problem to the soil/sediment, which has aroused a condense research into its treatment. In this thesis the zero valent iron coated with palladium was scattered by the use of carboxymethyl cellulose and selected as the treatment material. Furthermore, a direct current field was imposed into the polluted soil to drive the movement of NZVI/Pd within the soil to obtain an effective treatment. The main conclusions can be summed as followed:(1) The use of CMC can effectively solve the proble of aggregation caused by direct interparticle interactions such as vander Waals forces and magnetic interactions, which greatly improve the specific surface area. When used to treat the PCP both in the water and soil the material displayed a higher dechlorination performance.(2) Compared with the NZVI/Pd NPs, CMC-stabilized NZVI/Pd slurry displayed a better performance in PCP degradation both in solution and in the soil. In one hour the removal efficiency can be 79.8% and 61% respectively when the initial pH was adjusted to 5.5 and 7.0. Neverthless, the removal efficiency of PCP was 60% and 34% in the same reaction conditions when NZVI/Pd NPs were used as the treatment materials.(3) The pH value of the soil played an important role in the PCP adsorption process. The amount of PCP adsorbed in the soil decreased as the pH value increased. And the tendency fitted Langmiur equation.(4) After a running of DC field in the polluted soil for 15 days, only a slight amount of PCP was transferred out of the soil compared with the initial quality. But after a adjusting of the pH value to the solution in the cathodic reservoir, up to 91.9% PCP was removed from the polluted soil.(5) The combination of CMC/NZVI/Pd and the DC field displayed a good treatment efficiency to the PCP in the soil, the treatment efficiency can be about 94.3% mostof which was dechlorinated into phenol.