In Situ Amendments Research Of Carbonaceous Adsorbent For Organic Pollutants In Sediments

The pollution of Persistent Organic Pollution (POP) has become a global problem, in natural region, sediment is the source and sink of POP. Carbonaceous adsorbent is a kind of carbonaceous material made of coal or organic surface height of porous.Based on carbonaceous adsorbent has huge specific surface area and strong affinity role for POP, carbonaceous adsorbent can be used to repair the sediment. The addition of carbonaceous adsorbent as particulate sorbent to the biologically active layer of contaminated sediment is proposed internationally as an in-situ treatment method to reduce the biological availability of POPs. The research includes three parts:the adsorption thermodynamic experiment and adsorption dynamics experiment of carbonaceous adsorbent for DEHP (diethylhexyl phthalate); in situ repair dynamic simulation experiment of carbonaceous adsorbent; in situ repair field experiment of Carbonaceous adsorbent. The following results were obtained:(1) The experiment results of adsorption isotherms and adsorption dynamics show that:carbonaceous adsorbent has great specific surface area, when adsorption equilibrium is reached, The adsorption mass DEHP was Adsorbed in the surrounding space, reducing the quantity of DEHP released to liquid phase, So as to achieve the purpose of repairing DEHP pollution. The experiment results of isothermal adsorption fitted with Freundlich equation, Langmuir equation and DRM model equation, the n value of Freundlich equation is between0.6and0.7, the1/N value of DRM model equation is about1.1, This shows that the adsorption process is nonlinear intensely; In the fitting of dynamics equation, Secondary dynamics equation has the best fitting results, Elovich equation fitting results take the second place, Adsorption after48hours get basic balance state.(2) The results of in situ Amendments dynamic simulation shows that:Using carbonaceous adsorbent to in situ repair sediment, nine months later, among static equilibrium experiment, SPMD(semipermeable membrane device)enrichment experiments and XAD-4resin adsorption experiments, three PCB concentration value have been significantly reduced, the concentration of PCB in liquid decrement rate is 50%～80%, PCB in SPMD enrichment volume decrement rate is25%～72%, PCB resin adsorption volume decrement rate is30%～61%, all show the good repair effect.(3) The results of in situ Amendments field experiments shows that:After Adding carbonaceous adsorbent, the fixation chamber of section repaired with activated carbon was reduced of71%～124%, while the fixation chamber y of blank was reduced of47.5%, application carbonaceous adsorbent to in situ Amendments of sediment, has the very good prospects.