Strong enhancement on dye photocatalytic degradation by ball-milled TiO2:A study of cationic and anionic dyes

摘要

TiO_2 particles with desirable properties were produced by undergoing specific durations of ball milling.Characterizations of the TiO_2 particles before and after ball milling were investigated via X-ray diffraction(XRD), Brunauer-Emmett-Teller(BET), particle size analysis, zeta potential, and scanning electron microscope(SEM). The equilibrium adsorption data were well fitted to Langmuir, Freundlich, and Dubinin-Radushkevich(D-R) isotherms. Compared to the as-received TiO_2(mean particle size d150= 0.78μm, specific surface area = 88.17 m^2g^(-1), pore volume = 0.41 cm^3g^(-1)), the 60 min ballmilled TiO_2(d50= 0.55 μm, specific surface area = 99.48 m2g^(-1), pore volume = 0.48 cm3g^(-1)) enhanced the adsorption quantity of congo red and methylene blue from 10.4 mg g^(-1)to 13.6 mg g^(-1), and from17.0 mg g^(-1)to 22.2 mg g^(-1), respectively; and also improved the kinetic rates from k = 0.1325 to 0.2193, and k = 0.0944 to 0.1553, respectively. Dye adsorption and degradation efficiency of congo red was enhanced in acidic p H range(2–5.14), and methylene blue was enhanced in alkaline p H range(7.58–12).