Preparation Of TiO₂/PAN-Based Carbonization Nano-Fibers Composite Photocatalyst And Its Application In Humic Acid Photocatalytic Degradation

In recent years, photocatalyst TiO₂ shows capacious foreground in water treatment and air decontamination. The difficulty of recovery, low stability and denaturation problem in the suspending system can be resolved by immobilization. The nano-fibers prepared by electrospun method have small diameter, fast adsorption-desorption speed, steady physical-chemical characters. As carrier, nano-fibers can increase the contact probability between contamination and catalyst, it can be achieved that adsorption and photocatalysis cooperate with each other in the same reactor, the catalysis efficiency is enhanced very much.In this paper, the electrospinning and sol-gel are combined to prepare the TiO₂/PAN carbonization nano-fibers composite photocatalyst, the photocatalytst is applied in the humic acid (HA) photocatalytic degradation. In this study, composite photocatalyst is prepared under different conditions: electrospun solution concentration, pre-oxidation temperature, centrifugal and dipping time, HA is chosen to be the contamination of photocatalysis. The surface appearance, calorific ability, crystalline forms and grain size of TiO₂ are characterised by SEM,DSC and XRD methods. The HA photocatalytic degradation is studied under different conditions, the removal rates of HA solution UV₂₅₄ and TOC are compared. Concentrations of HA solution and pH are investigated for knowing the absorption capability of TiO₂/PAN carbonization nano-fibers composite photocatalyst to HA, and controlling the manipulating parameters better, based on this, the adsorption dynamics is studied. This study indicates nano-fibers with smaller diameter and intact surface form can be prepared under this conditions: the concentration of electrospun solution is 3%, pre-oxidation temperature is 280°C, the diameter mostly distribute at 120nm; When the centrifugal and dipping time are 1min and 2h, quantity of TiO₂ of composite photocatalyst is 22%, average grain size of TiO₂ is 10.9nm, which is small, these characters make the catalyst have good photocatalytic capability. The UV₂₅₄ can decrease 93%, while the concentration of catalyst and HA solution are 1.6g/L and 5mg/L, catalyst also keep high photocatalytic capability even be reused; Langmuir-Hinshelwood(L-H) model is used to simulate the dynamics of HA phtocatalytic degradation, interrelated coefficient is above 0.99. The adsorption investigation of catalyst to HA shows that pH is the significant factor which affects adsorption capability. The adsorption process of HA on the catalyst surface can be simulated by Langmuir, Freundlich adsorption equation and pseudo-first-order lagergren dynamic equation. Results show that the adsorption speed constant lowers as the concentration of HA solution increases, small concentration can get high removal rate.The composite photocatalyst prapated by electrospun and sol-gel methods has good adsorption capability as well as high photocatalytic capability. The investigation to phtocatalytic dynamic model can provide theory elements to forecast the degradation regulation of compound and reference foundation to design high efficiency, doable photocatalytic reactor.