Modification Of Chengdu Clay Pretreatment Of Municipal Solid Waste Leachate

The clay is a silicate mineral of the layered structure. This feature in its structure,resulting in the clay has many excellent properties, especially as a good adsorbent iswidely used in many manufacturing industries.Landfill leachate water quality is very complex, which contains highconcentrations of toxic and hazardous inorganic and organic matter, pathogenicmicroorganisms and certain tumor promoters and carcinogens belonging to the highorganic pollution in wastewater, its great harm. In this study, rich in mineral resources,inexpensive clay as adsorbent pretreatment of MSW leachate is an importantsupplement to the leachate pretreatment method.In this paper, cetyl trimethyl ammonium bromide (HDTMA), acrylamide (AM)and polyaluminum chloride (PAC) were used to modify Chengdu clay.The modifiedclay was devoted to landfill leachate treatment and the adsorption properties ofammonia nitrogen and COD for different modified clay were compared. Modifiedclays were characterized by X-ray diffraction, infrared spect-roscopy, thermalanalysis technique,analysizing the mechanism of action.Studies have shown that themodified clay pretreatment leachate method is feasible, modified clay of HDTMA isthe better modified.The optimal control conditions and the treatment effect of the three modifiedclays are as follows:(1) The optimal experimental condition of HDTMA modified clays: the dosageis100g, pH=7, rotational speed at200r/min (50min) and standing time of6h. Thetreatment effect for ammonia nitrogen removal efficiency is of48.68%and CODremoval efficiency is of32.27%.(2) The optimal experimental condition of AM modified clays: the dosage is100g, pH=7, rotational speed at200r/min (50min) and standing time of6h. Thetreatment effect for ammonia nitrogen removal efficiency is of31.82%and CODremoval efficiency is of23.34%.(3) The optimal experimental condition of PAC modified clays: the dosage is120g, pH=7, rotational speed at200r/min (50min) and standing time of8h. Thetreatment effect for ammonia nitrogen removal efficiency is of28.13%and CODremoval efficiency is of17.42%.The study also investigated the three modified clays on adsorption process ofammonia nitrogen and COD from the two aspects of adsorption thermodynamics andkinetics. The experimental results show that at303.15K,313.15K,333.15K, the equilibrium adsorption amount of ammonia nitrogen of HDTMA modified clayrespectively were8.62mg/g,8.20mg/g, and7.60mg/g; the equilibriumadsorption amount of ammonia nitrogen of AM modified clay respectively were5.66mg/g，5.00mg/g，4.70mg/g; the equilibrium adsorption amount of ammonianitrogen of PAC modified clay respectively were5.23mg/g，4.80mg/g，4.00mg/g.And the equilibrium adsorption amount of COD for the three modified clayat303.15K,313.15K,333.15K,were of HDTMA modified clay of52.20mg/g，44.20mg/g，37.20mg/g, of AM modified clay of37.64mg/g，31.64mg/g，23.64mg/g,of PAC modified clay of28.45mg/g，23.45mg/g，17.45mg/g. The three modifiedclays on the adsorption of ammonia are in line with the Langmuir isotherm andFreundlich isotherm model, the adsorption of COD is more consistent with theFreundlich isotherm model. Exothermic reactions are s-pontaneous and are in linewith the quasisecond order kinetic equation and the particle diffusion equation.