Study On The Degradation Of Textile Organic Dye Wastewater By TiO₂-based Nanomaterials

With the economic globalization and the sustainable development of the textile industy,the problems of enengy crisis and environmental pollution are also increasing,and becoming one of the major problems facing human society today.Eapecially,the pollution of organic dye wastewater generated in the textile printing and dyeing process,and the efficient degradation of dye wastewater is the current research hotspots.Titanium dioxide(TiO2)is widely used as a photocatalyst,supercapacitor and lithium ion battery as a promising semiconductor nanomaterial due to its low cost,non-toxicity,high reactivity and photoelectrochemical stability.TiO2 nano-photocatalytic oxidation degradation of printing and dyeing wastewater is an emerging and environmentally friendly new technology.This paper describes the modification of TiO2 nanomaterials defects mainly and applies to the photocatalytic degradation of Rhodamine B(RhB)and Methylene Blue(MB),which is the main pollutant of textile organic dye wastewater.In this paper,TiO2 ultra-long nanotubes were prepared by stirring hydrothermal method,then dopamine hydrochloride was added to polymerize into polydopamine(PDA)to form PDA@TiO2,which was stirred at room temperature with silver ammonia solution,and the reduction and adhesion of PDA were used to make Ag nanoparticles were reduced in situ and supported on the surface of PDA@TiO2 to form Ag@PDA@TiO2.Finally,TiO2 was transformed into anatase structure by calcination under inert gas,and PDA became a carbon source to obtain the final product Ag@C@TiO2,Due to the surface plasmon effect(SPR)of the Ag nanoparticles and the encapsulation of the carbon layer,the conductivity is increased,the solar absorption rate is enhanced,and the electron-hole pair separation efficiency is improved.The Ag@C@TiO2 nanocomposite photocatalyst was applied to degradate the RhB,which has an initial concentration of 50 mg L-1,exhibits excellent visible light photocatalytic degradation performance,2.5 times that of unmodified TiO2 ultralong nanotubes.The hydrogen production rate of Ag@C@TiO2 nanocomposite photocatalyst is also studied.It is 4.5 times that of TiO2 ultra-long nanotubes.After the study of TiO2 powder,considering the reusability,the composite photocatalyst of ZIF-67@TiO2 nanotube array was obtained by electrochemical deposition and hydrothermal method using anodized TiO2 nanotube array(TiO2 NTAs)as the substrate.In the subsequent calcination process,Co3O4 is derived from ZIF-67 with a porous structure,and the TiO2 NTAs are transformed from amorphous to anatase to form a p-n heterojunction.By comparing the MB photocatalytic degradation of Co3O4@TiO2 NTAs and ZIF-67-derived Co3O4@TiO2 NTAs.In a conclusion,ZIF-67 derived Co3O4@TiO2 NTAs have excellent cycle performance and better photocatalytic properties,which is 4.8 of pure TiO2 NTAs.Through the above two experiments,the photocatalytic properties of TiO2-based nanocomposites were significantly enhanced by two different modification methods.In addition,a simple preparation method was used to construct a visible light-induced photocatalyst for high-concentration dye wastewater,and a metal organic framework derivative was combined with a TiO2 nanotube array substrate to obtain a p-n heterojunction nanocomposite,which was provided a certain foundatio for subsequent research.