Preparation And Application Of ?-cyclodextrin Modified Vermiculite Adsorption Materials

With the rapid development of oil and gas industry,a large amount of untreated sewage water was discharged to damage the fresh water resource of our country.However,the complex polluted wastewater could not be effectively disposed by traditional adsorption material,thus it was necessary to research the economic environmental multi-function new adsorbent.This article designed a new adsorption material which has the structure characteristics of cyclodextrin and vermiculite,thereby greatly improving the adsorption performance of vermiculite.In this article,NaOH was regared as catalyst,?-cyclodextrins was modified by silane Coupling Agent(KH-560)to synthesis its derivatives(KMCD),then KMCD was grafted onto vermiculite to manufacture the modified vermiculite(KCMV).Conductivity(?/?s·cm-1)was introduced in the experiment to attain the optimal hydrolysis conditions:the pH value 4.0,hydrolysis temperature 25 ?,methanol concentration 10%,hydrolysis concentration of KMCD 40 g/L,hydrolysis time 15?32 h.Adsorption capacity(q)was regarded as indicator to inspect effect of adsorption amount of pollutants on the resulting products which were prepared under different conditions.Vermiculite was preprocessed with 2.0 mol/L of HC1,then the maximum adsorption amount could be reached at reaction temperature 85 ?,reaction time 16 h,vermiculite and KMCD with the quality ratio of 1:4.The structure of objective products were confirmed by characterization with Fourier transform infrared spectrum(FT-IR),nuclear magnetic resonance(1H NMR),Scanning Electron Microscope(SEM),X-ray diffraction assay(XRD),Brunauer-Emmett-Teller(BET)analyses,indicating that the P-cyclodextrins was grafted onto the surface of Vermiculite by this method.The adsorption ability of modified vermiculite for the removal of Cr(?),phenol and Cr(?)-phenol compound pollutants system were investigated.The adsorption mechanism and performance of renewable of KCMV were also studied.The experimental results showed that the adsorption capacity of KCMV was affected by particle size,adsorption time,dosage of KCMV,initial concentration of solution and pH value,et.Through the study of thermodynamics and kinetics to research the adsorption process of phenol and Cr(?),the results showed that adsorption process of phenol and Cr(?)conformed to pseudo-second order model;adsorption of Cr(?)was fitted with Langmuir isotherm adsorption model;adsorption of phenol accorded with Freundlich isotherm adsorption model;adsorption of Cr(?)and phenol were spontaneous endothermic process.Regeneration of experimental results indicated that KCMV was a good adsorbent with excellent adsorption properties and regeneration performance,which could be reused 5 times.The adsorption of Cr(?)-phenol compound pollutants system revealed that the removal efficiency of phenol and Cr(?)decreased due to the competition effect between the phenol and Cr(?),Phenol and Cr(?)adsorption were consistent with the pseudo-second order model,the concentration of Cr(?)had a great influence on the adsorption of phenol.