Solidification/stabilization Research Of Hazardous Waste Containing Nitrobenzene

Disposal of hazardous waste containing toxic organic is becoming increasingly important. The pollution characteristics of toxic organic is high toxicity and bio-gradable. Such as organic pollution problems of soil is getting attention. The migration behavior of toxic organic pollutants in the soil is decided by itself-nature (hydrophobic, volatile, stability, etc) at first. These toxic organic is easy to enter atmospheric environment from the soil environment; and partly is adsorbed on the suspended solid or caused surface water pollution with surface runoff in the soil; Because of the adsorption mechanism of soil particles, toxic organic caused pollution of groundwater with the rainfall or irrigation water. Due to the revision of the Identification Standard for Hazardous Wastes, there is an urgent demand for the treatment and management of such kind of hazardous waste. This paper has researched solidification / stabilization effect of cured product, which chose nitrobenzene as the representative of volatile organic. The long-term environmental security of cured product was evaluated under three kinds of simulated environmental.Nitrobenzene produced a huge impact on cement hydration process. The research of micro-structure of the solidified body shows that the process achieved an effective fixed mechanism, through the micro-structure of encapsulated and activated carbon physical and chemical adsorption of cured product. The cement solidification / stabilization technology can effectively deal with nitrobenzene of the soil, mainly from both volatilization and leaching to control. The results show that the right amount of activated carbon or organic bentonite can reduce the evaporation ratio of nitrobenzene effectively, but the leaching ratio of nitrobenzene has greatly improved.In order to protect the atmospheric environment, an appropriate amount of activated carbon or organic clay can be added in the solidification / stabilization process. The volatile concentration of nitrobenzene will be greatly reduced, but the leaching of nitrobenzene will be promoted at the same time. At this time disposal environment of cured product should be considered whether or not to add adsorbent. To protect the water environment, the cement solidification/stabilization technology can be directly used which will raise the fixation ratio to 90%.Research the leaching behavior of pollutant in long-term dynamic leaching test by simulating the different scenarios. The result showed that the long-term leaching process of pollutants included fast dissolution and slow diffusion. The leaching rate of nitrobenzene faster in the pre-leaching, but decreased significantly after the 45d. In the cement solidification test directly, the fixation ratio of nitrobenzene reached to 94% under the non-acidic precipitation, acid precipitation, sanitary landfill three kinds of scenarios. The leaching of pollutions is greatest under sanitary landfill scenario, so the product of solidification / stabilization which containing toxic organic hazardous waste would not be appropriate to conduct sanitary landfill disposal. The compressive strength of cured products was more than 2MPa to meet the requirements of landfill. When added 50% of cement and 1% of activated carbon, the compressive strength achieve to 10MPa which has to meet the demands of building materials.