Photocatalytic Decolourization And Degradation Of Methyl Orange By Chitosan/cds Nanoparticles Composite Film

In the applications of photocatalytic technology, nano（II-VI）families of the CdSis a kind of important inorganic semiconductor materials. For the CdS the band gap is2.42eV at room temperature. With unique optical, electrical, magnetic, mechanical andcatalytic properties, preparation of low production cost has a great application prospectin many fields. But at the same time, there exists a chemically active nano CdS,difficult to long-term preservation, recovery of difficult problems, such as by usingorganic media as the carrier, to modification of CdS nanoparticles, which caneffectively improve the stability of the CdS nanoparticles.In this thesis, Cadmium sulfide (CdS) nanoparticles were prepared using in situsynthesizing method in chitosan hydrogel films. While, in order to improve thephotocatalytic efficiency, respectively, the preparation of the transition metal Cu2+,Mn2+and rare earth elements of La3+doped chitosan/CdS nano composite membrane.The structure，the morphology，the element and absorbency of the films wereresearched with the tests of XRD、TEM and UV-Vis absorption Meanwhile thephotocatalytic performance of the films by using of methyl orange as evaluationstandards was studied．With ultraviolet light, the sun as the light source, degradation ofmethyl orange as the goal, the film for the photocatalytic degradation of organic dyeperformance. By changing the experiment conditions, the membrane in the process ofphotocatalytic degradation of methyl orange light conditions, reaction time, catalystdosing quantity, initial concentration of dyes, the influence of reaction factors such aspH light catalytic reaction, and through repeated experiments, the sustainability of thevalidation of catalyst activity.Results show that the dye has the best effect of degradation when the light catalystdosing quantity is0.7g/L; the concentration of methyl orange is15mg/L; the pH valueof acid. The kinetics of photocatalytic decolourization was found to follow apseudo-first-order according to Langmiur-Hinshelwood (L-H) model. CS/CdS films doping with Cu2+、 Mn2+and La3+can improve not only theperformance of the spectrum absorption but also the efficiency of the photocatalyticdegradation. Under ultraviolet light, Cu2+、 Mn2+and La3+doped composite membranedegradation rate were90%,94%and95%, respectively. In the sun, Cu2+、 Mn2+andLa3+doped composite membrane degradation rate were53%,73%and68%,respectively.