Modification Of Titanium Dioxide Nanoparticle And Adsorption Behavior For The Removal Of Cr (Ⅵ)

In recent years, with the rapid development of modern industry, followed by a large number of wastewater containing chromium, and how effectively reduced Cr(VI) to Cr(III) in control of wastewater pollution is a key issue. Nanoparticle TiO2has been used to adsorb heavy metals, the utilization of the sunlight by TiO2is low,and TiO2particles aggregate easily in the experiment, NH4Cl solution was added tetrabutyl titanate solution, the N will be doped into TiO2when Ti(OH)4in the event of Hydrolysis and condensation, it reported that chitosan has a high adsorption capacity of metal ions, after the doping of nitrogen in TiO2, chitosan coated on the surface of TiO2, TiO-N/CHS (Chitosan) nano materials were were produced, doped and coated TiO2, were adsorbent and photocatalyst which not easily resulted in aggregation and and the capacity of adsorption is better.Characterization of nano TiO-N/CHS and adsorption experiments were carried out, analysiseffect of the pH values, Cr(Ⅵ) initial concentration and reaction time, adsorbent dosage on the adsorption, research the adsorption isotherms and adsorption kinetic models of Cr (Ⅵ) on nano-TiO-N/CHS.The TEM image of nanoTiO-N/CHS is shown the particle size of nano-TiO-N/CHS is about10-20nm, within a certain range, chitosan improve the aggregation of nanoparticles. The diffraction peak of XRDaccording to the standard pattern of anatase TiO2, to calculate The average grain size of nano-TiO-N/CHS is about13.5nm.When the pH=2.5, initial concentration of Cr(Ⅵ) is100mg/L, the removal ratio of nano TiO-N/CHS of Cr (Ⅵ) was the highest, with the highest adsorption. The time required to achieve theadsorption equilibrium was about3h. Adsorbent dosage of3.0g/L is appropriate. It is found that the adsorption of Cr (Ⅵ)on nano TiO-N/CHS were fitted to the three adsorption isotherm models:Langmuir, Freundlich and Temkin equation,and the adsorption of Cr(Ⅵ) on nano-TiO-N/CHS were correlated well with the Freundlich equation as compared to the another equations,it can calculate the maximum adsorption capacity qm=61.35mg/g by Langmuir equation. The sorption kinetics may be described by the model and pseudo second order model, but not be correlated well with the intraparticle diffusion model.