Development Of Photocatalytic Treatment Equipment For Wastewater

With the rapid development of society and the progress in industrial production,all kinds of pollution have become more and more serious.But at the same time,the requirements for pollutant disposal have also been increasing.And,traditional methods of sewage treatment,such as adsorption,membrane separation and flocculation and sedimentation,have a lot of disadvantages,such as having insufficient treatment and being time-consuming.As a new method of sewage treatment,photocatalytic technology has many advantages,such as being more energy-efficient and recyclable.In order to promote photocatalytic technology,this paper has conducted a large number of researches in photocatalyst and photocatalytic sewage treatment plant.Among numerous semiconductor photocatalytic materials,Bi2O3 is a new efficient visible light photocatalyst.Its excellent performance has always aroused the attention of scientists.This paper adopts the high-temperature solid-state method.The bismuth powder was first loaded on the surface of the alumina pellet by ball milling,then bismuth oxide photocatalytic material was prepared by high-temperature calcination.This preparation technology can regulate the burning temperature to produce bismuth oxide materials of different specifications.Through screening,it can be inferred that the best photocatalytic effect could be obtained when the calcination temperature was 873K and calcination time was 5h.This paper has conducted an innovative design on the structure of photocatalytic sewage treatment plant by means of relevant theories and methods in mechanical design,analyzed the structure design features and functions of shaft connection and sealing system,aeration and mixing system,cooling circulation system,light source system and gas connection pipeline and other parts of the plant.And it also emphatically discussed the installation method and design concept of aeration and mixing system.The virtual design of the plant was completed with the software SolidWorks2016 as the design platform.In this design,the most important part is the aeration and mixing system,which is not driven by an electric motor.Its blade rotation is driven by the reverse thrust of a compressed gas ejection.The gas ejection could be used as aeration medium;and blade speed could be controlled by compressing gas pressure.This system is composed of blades,spindle,flange,flange end cover and air compressor.According to calculation and experience,the blade diameter is 109mm;the spindle diameter is 32mm;the blade angle is 10?15°;the maximum pressure of the air compressor is 0.8MPa.Finally,the photocatalytic sewage treatment plant designed in this paper is used as the prototype,Malachite green solution as the pollutant,self-made ball-milled bismuth oxide as the photocatalytic material.A series of photocatalytic experiments have been conducted.Through the analysis of experimental data,the optimal process parameters of the sewage photocatalytic treatment device under the existing experimental conditions were obtained:reaction time is 180min,dosage of photocatalyst is 12.5g,air pressure is 0.8MPa,light source power is 400W,external bias is 0.6V,and solution PH value is 4.In this process,the photocatalytic degradation rate of bismuth oxide reached 92.8%,which is significantly better than that of 86.6%using the experimental photocatalytic instrument.