Abstract: Wintermelon-based TiO₂ carbonaceous aerogel(WTCA) composites were prepared by hydrothermal reaction and freeze drying process with wintermelon and tetrabutyl titanate as precursor. The Rhodamine B(RhB) wastewater was photodegraded by WTCA under visible light irradiation. The effects of various common inorganic salt ions in water on the photodegradation were also studied systematically. The morphology structure and properties of as-prepared samples were characterized by using X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Raman spectrometer,and fluorescence spectroscopy(FL). XRD,Raman and EDS analysis results showed that anatase titanium oxide and carbon element appeared in the WTCA. SEM and TEM analysis results showed that TiO₂ nanoparticles were homogeneously anchored on the skeleton surface of hierarchical carbonaceous aerogels. Meanwhile the composite aerogels exhibited better photodegradation capacities for the RhB than pure TiO₂. The photocatalytic effect of WTCA had the best photocatalytic efficiency(96.11%) when TiO₂ load up to 30%. Moreover,the inorganic salt anion ions had the negative effect on photodegradation effect with the order of CO₃^2- > SO₄^2- > Cl^- > NO₃^- while the inhibitory effects of cationic ions(Na⁺,K⁺,Ca²⁺ and Mg²⁺) were not obvious.

Key words: wintermelon-based carbonaceous aerogels, TiO₂, photodegradation efficiency, inorganic salt ions