The Effect Of Fluidized Bed-Fenton System On Dyeing Wastewater Treatment

Fenton technology is widely used because of its advantages such as simple operation,low operation cost and good treatment effect of organic pollutants.At the same time,the narrow application scope of p H and the large amount of iron mud limit its engineering application,to some extent.This paper attempts to prepare a new type of iron-oxide catalyst and build fluidized bed-Fenton system.Through a series of single-factor experiments,the preparation conditions of the catalyst and the optimum parameters for the treatment of dyeing wastewater were explored.The system can both ensure the degradation efficiency of conventional Fenton,and reduce the amount iron mud.The operating parameters of the fluidized bed-Fenton were optimized.This paper puts forward a practical and feasible improvement method for the conventional Fenton technology.First,taking the building sand as the carrier matrix,the catalyst was loaded in the fluidized bed-Fenton reactor by the cyclic immersion method,and the operation mode of the reactor is running continuously.In order to speed up the iron-carrying rate of the carrier and shorten the start-up time of the fluidized bed-Fenton system,this paper pulled-in some dyeing waste into the system,and puts the iron powder and Fe2O3 into the reaction system at a certain frequency.In this paper,the single factor method was used to optimize the preparation conditions of the catalyst.The results showed that the iron-loading rate of the building sand was greater than that of the quartz sand under the same conditions;the actual wastewater could improve the iron carrier rate of the carrier matrix,and the iron bearing rate of the carrier matrix was greatly increased by the addition of the iron powder and Fe2O3.The scanning electron microscopy results showed that the surface of the catalyst was attached to a layer of cracked iron oxide.The X-ray diffraction results showed that the main components of the iron oxide were Fe OOH and Fe2O3.Then,taking the actual dyeing wastewater as the target wastewater,the optimum parameters of conventional Fenton and fluidized bed-Fenton were explored.The experimental results showed that the best parameters of dyeing wastewater treatment by conventional Fenton are: p H value is 3,Fe2+/H2O2 is 1:4,COD/H2O2 is 1:2: the optimum parameters for treating the same dyeing wastewater by fluidized bed-Fenton are as follows: p H value is 4,Fe2+/H2O2 is 1:6,COD/H2O2 is 1:2.The efficiency of dyeing wastewater treatment by conventional Fenton and fluidized bed-Fenton under the same conditions was compared.When the reaction time was 240 min,the removal rate of COD was 69.77% and 78.57%,respectively.Compared with the conventional Fenton,the total iron content in the fluidizedbed-Fenton system was reduced by 88%.When the COD degradation rate to the dyeing wastewater of the two processes is similar,the total iron content in the fluidized bed-Fenton system was reduced by 87.25% compared with the conventional Fenton,the fluidized bed-Fenton shows a good effect on the reduction of iron mud.Finally,the operation parameters of the fluidized bed-Fenton were optimized.The results showed that when the amount of catalyst is 1/8 and the expansion rate of catalyst is 75%,the total iron concentration of the fluidized bed-Fenton system is the lowest.Compared with the side-swirling water distributor,the downstream water distribution is more convenient.Intermittent operation is more conducive to reducing total iron concentration in fluidized bed-Fenton reactor.In addition,the fluidized bed-Fenton system showed a good removal effect on and dyeing wastewater in the p H value range of 3~6,which widened the p H value of the conventional Fenton.The initial amount of Fe2+in fluidized bed-Fenton system was reduced by 30% compared with the conventional Fenton,which is of great significance for the engineering popularization of fluidized bed-Fenton technology.