Effect Of Natural Organic Matter On Removal Of Trichloroethylene Using Fenton-like Reagent

With the fast development of society and industry, water shortage andgroundwater pollution are becoming more serious for the people. Trichloroethylene(TCE), a kind of persistent organic pollutants, is found in soils and waters because ofits overuse and disposal, and thus has potential higher risk to human beings. Thegroundwater is easy to be contaminated by TCE, which could get through the soilpore and form pollution plume in the deep underground.The system of iron-bearing minerals as catalysts with hydrogen peroxide, oftencalled Fenton-like reagent, is used in advanced oxidation process for removal oforganic pollutants. However, natural organic matter (NOM), a complex mixture oforganic compounds widely present in soil and water, could affect such water treatment.NOM consists of many types of function group and different range of molecularweight organic compounds, and it plays a significant role in transport, conversion,deposition and bioavailability of heavy metal and organic pollutants on the earth.Batch experiments were designed for TCE removal by Fenton-like reagent usingiron-bearing minerals. In particular, the effect of NOM on this system was studied.The results showed in the following.1）Siderite catalyzed hydrogen peroxide forTCE degradation is the best one among minerals of magnetite, siderite and hematite.2)NOM mitigated the removal of TCE by Siderite Fenton-like system.3) Someindicators were measured in the process and mechanism was discussed. It was foundthat NOM has some inhibitory effect on generation of iron ion and hydroxyl radical.XPS characterization showed that some NOM adsorbs on the surface of siderite, andit might be useful to enhance electron transfer and iron ion movement.4) On the otherhand, low concentration of NOM in the water could be removed by Fenton-likereagent.5) From thermodynamic calculation, Gibbs free energy of reaction indicatesthat chlorine gas could not generated by hydroxyl radical and chloride ion in thisadvanced oxidation process of TCE removal, which also indicates it is anenvironmental benign approach.