Photocatalytic Degradation Of Methylene Blue Solution By Titania Fine Particles

As the dye of the rapid development of the textile industry, dyes and the increasing number of varieties, printing and dyeing wastewater stream environment has become one of the key sources of pollution. Methylene blue as dyeing wastewater in one of the typical organic pollutants, printing and dyeing is an important target of sewage treatment. This paper against the reality of this serious pollution problem, choose the most promising development of environment-friendly materials nano-photocatalytic TiO₂ as a degradation of methylene blue light catalyst, photocatalytic degradation of research, to deal with the actual printing and dyeing waste water to provide an efficient and economically feasible method.Preparation of samples through the Sol-Gel method doped Fe³⁺, Zn²⁺, V⁵⁺, Cr³⁺, Ce⁴⁺, Si⁴⁺ nano-TiO₂ catalyst, using XRD, SEM, TG-DSC, and other modern tests of the instruments, methods and means to study the relationship between the structure and composition of samples and the photocatalytic properties of TiO₂ sample.XRD patterns analysis showed that the roasting temperature of the sample preparation phase of the decisive role. From 400℃to 700℃were roasting 2h samples, 400℃roasting the samples to be pure anatase nano-TiO₂, XRD spectrum of anatase in only the diffraction peak; 450℃of a sample of rutile diffraction peaks shows that have been part of anatase nano-TiO₂ started to change into rutile nano-TiO₂; 700℃samples of all the basic rutile diffraction peaks at this time that anatase TiO₂ has completely changed into rutile nano-TiO₂. The doped ion Fe³⁺ promote anatase TiO₂ change into rutile, and the amount of Fe³⁺ doping samples have inhibited the growth of grain size. The doped ion V⁵⁺ restrain anatase TiO₂ change into rutile TiO₂.SEM photo shows, with the baking temperature increases, the handling of doping nano-TiO₂ particles reduce the extent of reunion. Doping 1% Fe³⁺, the samples were mostly spherical particles, the better dispersion of samples. Fe³⁺ doped with the increase, the more serious particles reunion; With the increase of V⁵⁺ doping, nano-TiO₂ particles dispersed more evenly.V⁵⁺ doped laser particle size distribution map shows that the doped V⁵⁺ from 1% to 5%, the size distribution of powder narrows, when n(V) : n(Ti) = 0.05, the size distribution of the smallest particle size distribution of samples on 0.55 - 0.62μm.Preparation of the samples parameters photocatalytic degradation of methylene blue activity has greatly affected. Roasting temperatures were 400℃, 450℃, 500℃, 600℃and 700℃, doping different component, high-temperature roasting activity in different: pure TiO₂ and doped Fe³⁺TiO₂ in the 450℃roasting 2h samples of the activity relative best, and doped Zn²⁺, V⁵⁺, Cr³⁺, Ce⁴⁺, Si⁴⁺ samples were in the 500℃, 500℃, 500℃, 600℃, 700℃roasting the photocatalytic activity relative best. Different ion doping samples, doping of its photocatalytic properties affected, Fe³⁺, Ce⁴⁺, Zn²⁺, V⁵⁺, Cr³⁺ incorporation of 0.5% of the degradation of methylene blue relative effect of the best, and Si⁴⁺ doped the amount of 5% of the degradation of methylene blue relative effect of the best.Roasting temperature increases can lead to TiO₂ UV red shift, but the efficiency of TiO₂ photocatalytic degradation of methylene blue is not increased, spectral shift is conducive to raising sample spectral response, but light activity factors is complex and photocatalytic activity is also subject to the impact of many factors such as sample crystal structure, particle size, surface area and so on.Catalyst amount too high or too low-activity not conducive to the improvement in our test under the condition of the concentration of 1g/L catalyst for the photocatalytic effect of relatively good.If the degradation of organic matter concentration was too high, the catalyst activity will be effected by the product of the reaction. In this paper experimental conditions, methylene blue for the initial concentration of 5mg/L degradation rate faster.