Acidic Montmorillonite/Cordierite Monolithic Catalysts for Cleavage of Cumene Hydroperoxide

In this work,a series of acidic montmorillonite/cordierite monolithic catalysts were prepared by a coating method using silica sol as the binder.The morphology and structure of the acidic montmorillonite/cordierite samples were characterized by means of X-ray diffraction(XRD),N_2 adsorption/desorption isotherms,and scanning electron microscope(SEM).The cleavage of cumene hydroperoxide(CHP) in a conventional fixed-bed reactor was chosen as a model reaction to evaluate the catalytic activity of the monolithic catalysts.The influences of acidic montmorillonite loading,reaction temperature.CHP concentration,and weight hourly space velocity(WHSV) on the catalytic activity and selectivity of phenol were studied.The results indicated that the obtained acidic montmorillonite/cordierite monolithic catalysts were firm and compact,and the loading of acidic montmorillonite was found to reach 40%(by mass) after three coating operations.The surface area of acidic montmorillonite/cordierite catalysts increases greatly as acidic montmorillonite loading increases due to higher surface area of acidic montmorillonite.Under the optimal reaction conditions(acidic montmorillonite loading of 32.5%(by mass),temperature of 80 ℃,a mass ratio of CHP to acetone of 1:3,and WHSV of CHP of 90 h^(-1)),the conversion of CHP can reach 100%,and the selectivity of phenol is up to 99.8%.

A Facile Method for Dye and Heavy Metal Elimination by p H Sensitive Acid Activated Montmorillonite/Polyethersulfone Nanocomposite Membrane

Modified clay/polyethersulfone（PES） mixed matrix membranes（MMMs） were prepared by acid activated montmorillonite（AA-MMT） with different concentrations and used to eliminate dyes and remove heavy metals from aqueous solution. The morphology and physiochemical properties of prepared clay nanoparticles and MMMs were characterized using X-ray diffraction（XRD）, Fourier transform infrared（FTIR） spectroscopy, scanning electron microscopy（SEM）, enegy dispersive X-ray（EDX） spectroscopy, Brunauer-Emmett-Teller（BET） analysis, atomic force microscopy（AFM）, contact angle measurement and fouling studies. The filtration study showed that removal of dyes and heavy metals was strongly dependent on p H so that dyes with positive and negative charges showed different separation efficiency in acidic and alkaline conditions. The modified membranes possessed better heavy metal removal in acidic and alkaline p Hs. When the rejection of heavy metals was measured in an alkaline environment, it was observed that the rejection had a great increase compared to the neutral values for Zn^（2＋） and Ni^（2＋） ions, while rejection of Cu^（2＋） and Cd^（2＋） did not undergo significant changes. So it can be concluded that modified membranes show good selectivity for elimination of Zn^（2＋） and Ni^（2＋） ions with respect to other cations.