Investigation Of Sorption Of Wastewater On Modified Halloysite

Here, halloysite was selected as the basic adsorption materials which are rich in our country. The halloysite was modified by taking physical and chemical methods, and using infraredspectroscopy, X-ray diffraction, scanning electron microscopyand other testing methods to characterize them. UO22+, Gd2+, octadecylamine, Phenol adsorption performance were investigated by using a static test batch of these materials,anddiscussed the influence of adsorption time, adsorbent concentration, pH, ionic strengthand other factors. The experimental results are as follows.（1） Magnetic halloysite composite was synthesized by chemical co-precipitation and its sorption behavior was investigated. Magnetic halloysite composite was characterized by Fourier transfer infrared（FT-IR）, X-ray diffraction, Transmission Electron Microscope（TEM） and vibrating sample magnetometer（VSM）. The sorption behavior of magnetic halloysite for octadecylamine and UO22+ were studied as a function of solid content, contact time, pH and temperature. The equilibrium data were analyzed using the Lagrange pseudo-second order kinetic model, Langmuir isotherm and Freundlich equation. The results manifested that magnetic halloysite composite was successfully obtained. The process of sorption was strongly affected by pH and temperature. The sorption of magnetic halloysite for octadecylamine and UO22+ were found to follow the pseudo-second-order kinetic model. With respect to thermodynamics, sorption of octadecylamine and UO22+ increased with increasing temperature and fitted the Langmuir isotherm.（2） Halloysite nanotubes（HNTs） were surface modified with KH550 to form the novel HNTs-KH550 composites, and its sorption behavior was investigated. HNTsKH550 composite was characterized by Fourier transfer infrared（FT-IR）, X-Ray Diffractometer（XRD） and Thermo Gravimetric（TG）. The sorption behavior of HNTs-KH550 for Cd2+ was studied as a function of solid content, contact time, pH and temperature. The equilibrium data were analyzed using the Lagrange pseudo-second order kinetic model, Langmuir isotherm and Freundlich equation. The results manifested that HNTs-KH550 composite was successfully obtained. The process of sorption was strongly affected by pH and temperature. The sorption ofHNTs-KH550 for Cd2+ was found to follow the pseudo-second-order kinetic model.With respect to thermodynamics, sorption of Cd2+ increased with increasing temp erature and fitted the Langmuir isotherm.（3） TiO₂ nanocrystals were absorbed on the surface of natural halloysite nanotubes（HNTs） by means of sol-gel method to form the HNTs-TiO₂ composites, which effectively controlled the aggregation of TiO₂. The XRD, TEM and IR indicated that TiO₂ nanocrystals were successfully absorbed on the surface of HNTs. The influences of calcination temperature, catalyst loadings and times of catalyst usage were investigated. The results indicated that the optimum conditions were as follows:calcination temperature = 100℃, HNTs-TiO₂ catalyst loadings = 0.2 g/L. Degradation rate of 73.3% was attained for 33 mg/L phenol-containing water after illumination for 9h.