Adsorption and photocatalytic degradation of dyes on polyacrylamide/calcium alginate/TiO2 composite film

A casting solution was prepared by dispersing titanium dioxide (TiO2) nanoparticles in the sodium alginate and acrylamide aqueous solution. The casting solution was spread on a glass plate by a glass rod enlaced with brass wires to control the thickness of the sticky solution. Then polyacrylamide/calcium alginate/TiO2 (PAM/CA/T) composite film was obtained after UV irradiation and cross-linking by CaCl2. The PAM/CA/T film was characterized by scanning electron microscope and transmission electron microscope. The PAM/CA/T film had good strength and toughness. And they did not rupture after swelling in 5 wt.% NaCl solution and still had good mechanical properties. The adsorption properties of the PAM/CA/T film were investigated by using different dyes as the adsorbates. The photocatalytic degradation properties of these dyes on the PAM/CA/T films were also researched. The results indicated that there was no difference in the adsorption efficiency of PAM/CA film and PAM/CA/T-30 film. The adsorption rates of all the dyes were fast. The pre-adsorption of dyes had little effect on the catalytic degradation of dyes on PAM/CA/T film. The PAM/CA/T hydrogel film provided a suitable carrier for TiO2 in the photocatalytic degradation of dyes and the degradation efficiency of PAM/CA/T-30 film for methyl orange reached 80.76%. The PAM/CA/T film had good reusability and could degrade dyes in NaCl solution.