TiO₂-RGO Composites For Treatment Of Tetracycline Antibiotic Wastewater

Tetracycline antibiotic wastewater is currently a big problem for the water treatment, because that it is difficult to degradation. Titanium dioxide (TiO2) materials with low cost, non-toxic, and the advantages of stable performance, is generally believed to be one of the most research prospects of photocatalytic materials. However, the electrons generateed from light and holes in TiO2 are easily to combine, which often results in poor photocatalytic efficiency. At the same time, the morphology of TiO2 structure also affects the efficiency of photocatalysis.The main content of this paper is as follows:TiO2 nanocubes grown on the surface ofreduced graphite oxide was synthesized using ethanol and ethylene glycol as mixed solvent, tetrabutyl titanate as titanium source, through the solvent thermal reaction. After calcination under the protection of inert gas, the graphite oxide (GO) was reduced and became graphite oxide (RGO). Meanwhile, the TiO2-RGO composite could be obtained. By changing the amount of raw tetrabutyl titanate, different proportion of titanium dioxide was synthesized. X-ray Diffraction(XRD), X-ray photoelectron spectrum (XPS) and IR were used to characterize the structure of the composite, and thermogravimetric test was used to confirm the titanium dioxide content in the compound. SEM images showed 200-400 nm nanocube grown on reduced graphite oxide layers. Ultraviolet diffuse test demonstrated that the composite have good photocatalytic performance under ultraviolet light. Titanium dioxide, graphene and the composite was used as the photocatalyst to degrade waste water containing oxytetracycline hydrochloride and doxycycline hydrochloride. The best reaction condition was determined in the absence of light with the adsorption equilibrium time of 30min. When treated at pH at 7 for 2 h, the degradation reaction rate was 88.59%. The impact of catalytic dose was not that obvious. The titanium dioxide graphene compound with initial concentration of 30 mg/L,40 mg/L,50 mg/L were used to photocatalytic degrade wastewater containing oxytetracycline hydrochloride, indicating that the greater initial concentration, the more obvious effect can be obtained. Also the best photocatalytic properties of the synthetic compounds recovery and repeatability tests have been carried out to verify the photocatalyst repeatedly using the influence of the light catalytic degradation reaction rate, which show that the reaction rate 3 times before reuse have better degradation rate, which were 87.92%,87.22% and 66.41% respectively. Finally, the reaction kinetics of photocatalytic degradation of oxytetracycline hydrochloride is discussed, all the reaction can match pseudo-first-order reaction kinetics, and titanium dioxide graphene composite oxytetracycline hydrochloride wastewater treatment the best reaction rate constant was k= 0.01.