Preparation Of Bi₃O₄Br/HTCN/Polyester Fabric And Its Degradation?removal Of Organic Pollutants

Organic pollutant in water seriously endanger the survival of organisms.The contamination of the aquatic environment is becoming a serious problem.Water pollution is caused by the introduction of variety of organic pollutants and residual dyes from different sources.Traditional treatment methods have problems such as long cycle,cumbersome procedures,expensive and secondary pollution.Photocatalytic technology is an emerging environmental purification technology that can effectively repair water pollution,directly using visible light as the driving force and oxygen as an oxidant,decomposing organic pollutants into inorganic small molecules such as carbon dioxide and water,and the purification effect is thorough,the research and application of photocatalytic materials has great practical significance.Therefore,Bi OBr/g-C₃N₄photocatalytic materials appeared.However,the Bi OBr/g-C₃N₄ material has the problems of weak visible light responsiveness and limited catalytic performance,there are application limitations such as poor dispersion stability,difficult recovery and inability to recycle when used as powders.In this paper,new materials of bismuth-rich Bi OBr and hollow tubular g-C₃N₄ and polyester(Bi₃O₄Br/HTCN/polyester)were constructed based on Bi OBr/g-C₃N₄ materials.The preparation conditions,structural characterization and application performance and mechanism of Bi₃O₄Br/HTCN/polyester fabrics for the degradation and removal of tetracycline(TC)and reactive brilliant blue KN-R(RB-19)were studied.The main contents are as follows:(1)Preparation of Bi₃O₄Br/HTCN material.Hydrothermal method was used to prepare Bi₃O₄Br by adjusting the p H value of the reaction solution,HTCN was prepared by calcination method,and Bi₃O₄Br/HTCN material was prepared by ultrasonic stirring method.The effect of photocatalytic performance.The results show that the chosen p H of the hydrothermal reaction is13,the preparation temperature is 180?,the preparation time is 12h,the temperature of the calcination experiment is 550?,and the Bi₃O₄Br:HTCN=10:1(mass ratio),the Bi₃O₄Br/HTCN material has excellent photocatalysis performance,the degradation and removal efficiency of TC and RB-19 is higher.(2)Performance characterization of Bi₃O₄Br/HTCN material.The microscopic morphology of Bi₃O₄Br/HTCN material was characterized by SEM and TEM analysis,which proved that two-dimensional sheet-like Bi₃O₄Br and tubular g-C₃N₄ were successfully prepared,and the two were uniformly dispersed and composited with good surface-to-surface contact;XRD,FT-IR analysis of the crystal forms and groups of Bi₃O₄Br,HTCN,Bi₃O₄Br/HTCN materials,the results show that the prepared Bi₃O₄Br has a high crystallinity and contains Bi-O characteristic peaks,HTCN contains tri-s-triazine characteristic peaks,and Bi₃O₄Br/HTCN contains both Bi-O and tri-triazine characteristic peaks;the elements and valence states of the Bi₃O₄Br/HTCN material were analyzed by means of XPS and EDX,and the elements of C,O,Bi,N,and Br were uniformly dispersed;the specific surface area of the Bi₃O₄Br/HTCN material was analyzed by BET,indicating that after the composite The specific surface area was increased;the photoelectric properties of Bi₃O₄Br/HTCN materials were analyzed by transient photocurrent,which showed that the photocatalytic activity of Bi₃O₄Br/HTCN materials was improved compared with that of Bi₃O₄Br and HTCN.(3)The possible degradation mechanism of Bi₃O₄Br/HTCN material.Through the dark reaction adsorption experiment and the photoreaction degradation experiment,it is determined that the degradation of Bi₃O₄Br/HTCN material may be the result of the combined action of physical adsorption and photochemical reaction.The photoelectric properties of Bi₃O₄Br/HTCN material were analyzed by PL,EIS and other methods,indicating that the photogenerated carrier excitation and separation efficiency of Bi₃O₄Br/HTCN material were enhanced.Using the Mott-Schottky curve analysis,the conduction band positions(E_CB)of Bi₃O₄Br and HTCN can be estimated to be 1.12 e V and-0.89 e V,respectively,and the valence band positions(E_VB)are 3.34e V and 1.70 e V,respectively.Bi₃O₄Br and HTCN are both n-type semiconductors.The photocatalytic mechanism was deduced;·O₂^-and h⁺were determined as the main active species by means of ESR test and free radical capture experiment,and·OH played a synergistic role;LC-MS was used to analyze the degradation intermediates of tetracycline,and the possible degradation paths were deduced.(4)Preparation and performance analysis of Bi₃O₄Br/HTCN/polyester fabric.Take 0.2g Bi₃O₄Br/HTCN material,0.01 g polyvinylpyrrolidone K30 in a beaker,add 100 m L triple distilled water,ultrasonic dispersion for 10 min,stir and heat to 85°C,put in a piece of 5 cm×5cm polyester fabric,slowly stir and keep warm for 120 min,and finally remove the composite polyester fabric,wash it with triple distilled water slowly,bake at 160°C for 3 min,dry at 60°C,and obtain the Bi₃O₄Br/HTCN/polyester fabric used in the experiment.The degradation efficiency of Bi₃O₄Br/HTCN/polyester fabric to TC with 93.15%at the time of 90 min,and the degradation efficiency of RB-19 with 90.28%at the time of 90 min.The degradation rates of Bi₃O₄Br/HTCN/polyester fabrics on TC and RB-19 remained 89.82%and 88.33%after five cycles of degradation.