| As one kind of industrial wastewater,dye wastewater is difficult to treat.It has high chroma and also contains lots of organic pollutants that are difficult to degrade.Coupling the three-dimensional electrode technology and the electric Fenton technology can not only improve the reaction efficiency,but also increase the production of oxidants,such as hydroxyl radicals.While,the particle catalyst is the core of the combined technology.In this paper,steel slag,which is a kind of industrial waste,has been used as particle catalyst to construct a three-dimensional electro-Fenton(3D-EF)system to treat dye wastewater.The parameters of the reaction have been optimized and the reaction mechanism has been preliminary studied.The thesis also compares the effect of 3D-EF system and 2D-EF system on dye wastewater treatment and energy consumption.Then the 3D-EF system was applied to the treatment of other simulated dye wastewater to explore whether the 3D-EF method can be widely used in the treatment of dye wastewater,which can provide an erperimental basis for the industrial application of this system.The research work of this paper is as follows:A series of factors affecting the degradation effect of methylene blue in the three-dimensional electro-Fenton system were optimized.The changes in the concentration of iron ions in the solution at different p H were studied,the effect of hydro radical scavenger on the treatment effect was explored and the recycling performance of the steel slag was explored.The results show that the optimal reaction conditions for the steel slag three-dimensional electro-Fenton system to degrade methylene blue are: the initial concentration is 10 mg·L-1,the current density is 15 m A·cm-2,the concentration of electrolyte is 0.15 M,the initial p H is 4,the steel slag is 4 g,the aeration amount is 4 L·min-1 and the distance between cathode and anode is 4 cm.The concentration of iron ions leached in the methylene blue solution decreased with the increase of the initial p H value of the solution,which proves that the hydroxyl radical mainly comes from the heterogeneous electric Fenton reaction in the steel slag.After the addition of tert-butanol,the removal rate of methylene blue was reduced by 35.865% compared with the absence of tert-butanol,which shows that the degradation of methylene blue was greatly inhibited after the addition of tert-butanol.While tert-butanol is the quencher of hydroxyl radicals,indicating that after the system loses hydroxyl radicals,the degradation of methylene blue is greatly affected.It also shows that the effect of hydroxyl radical on the treatment effect of methylene blue plays a major role.After multiple cycles of steel slag,the removal rate of methylene blue in the system continued to decrease.However,after five cycles of steel slag particles,the removal rate of methylene blue is still above 80%,indicating that steel slag particles have excellent recycling performance and have great potential in industrial applications.The treatment effects of 3D-EF system and 2D-EF system on simulated wastewater of methylene blue were compared,and the electrochemical energy consumption of the two methods was compared by establishing a mathematical model of energy consumption.Then,the steel slag three-dimensional electro-Fenton system was used to treat other simulated dye wastewater such as neutral orange,direct red brown and active turquoise.The results show that the three-dimensional electro-Fenton system has shorter reaction time,faster reaction rate,and higher electrochemical efficiency than the two-dimensional electro-Fenton system under the same reaction conditions.When the removal rate of methylene blue is high,the three-dimensional electro-Fenton method saves more energy than the two-dimensional electro-Fenton method.The steel slag three-dimensional electro-Fenton system exhibited excellent degradation effect on neutral dyes represented by neutral orange,direct dyes represented by reddish brown,and reactive dyes represented by reactive turquoise. |
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