Surface modification of zeolite with beta-cyclodextrin for removal of p-nitrophenol from aqueous solution.

The surface of zeolite was modified by cationic beta-cyclodextrin (CCD), which was synthesized with 2, 3-epoxypropyltrimethylammonium chloride (ETMAC) and beta-cyclodextrin (beta-CD), to prepare a novel and effective sorbent for removal of p-nitrophenol (p-NP) from aqueous solution. FTIR, SEM and EDS were used to characterize the surface modification. It was found that CCD, which was synthesized at different conditions such as the mole ratio of ETMAC against beta-CD and pH, made an impact on sorption capacity of p-NP on CCD-modified zeolite (CCDMZ). Given ETMAC: beta-CD = 7:1 and pH = 13, the cationic process of beta-CD might be optimum for CCD to bond to zeolite surfaces. In addition, CCD concentration and modification time affected sorption capacity of p-NP on CCDMZ too. The sorption of p-NP on CCDMZ, activated zeolite (AZ) and natural zeolite (NZ) was investigated by contact time, initial p-NP concentration and sorption isotherms with the batch sorption experiments. The results showed that the sorption of p-NP on CCDMZ satisfactorily fitted the known Langmuir model and the sorption capacity of CCDMZ was higher than that of AZ and NZ although the contact time of CCDMZ appeared to be shorter than other two.