Performance Study Of Molybdenum Disulfide-loaded Graphene Composites For Co-catalytic Fenton Reaction Degradation Of Orange Ⅱ

Printing and dyeing wastewater is a common industrial wastewater with high concentration,strong pollution,high alkalinity and COD value.Traditional biological and physical methods have poor treatment effects,so researchers usually turn their attention to chemical treatment methods.Among them,the Fenton advanced oxidation technology is widely used as an efficient and environmentally friendly chemical treatment method.However,its main disadvantage is that the reaction efficiency is greatly affected by environmental factors,and the optimal reaction p H is below 3,and it is easy to produce iron sludge and other problems.Therefore,the current use of co-catalysts to further improve the efficiency of Fenton reaction is an effective way to achieve efficient removal of organic pollutants.This paper studies the degradation performance and degradation mechanism of organic dyes by preparing composite materials of molybdenum disulfide（Mo S₂）,zero-valent iron（ZVI）,and graphene oxide（r GO）and applying them to assist in catalyzing the traditional homogeneous Fenton system.The specific research content and conclusions are as follows.:（1）Flower-like Mo S₂/r GO composite material was applied as an assistive catalyst in homogeneous Fenton system for the degradation of Orange II.Experimental results showed that compared with traditional homogeneous Fenton system,Mo S₂/r GO assisted Fenton system achieved nearly 100%degradation of Orange II within 30 min,and the first-order kinetic constant for Orange II degradation was 0.1712 min^-1,which was 17 times higher than that of traditional Fenton system.The composite system had a wide p H adaptability and strong resistance to environmental factors,and could still achieve rapid degradation of Orange II under neutral and alkaline conditions with a p H of 11.Free radical quenching experiments and electron paramagnetic resonance（EPR）results confirmed the existence of hydroxyl radicals（·OH）,singlet oxygen（¹O₂）,and superoxide radicals(O₂^·-)in the system,which catalyzed the degradation of Orange II together.The X-ray photoelectron spectroscopy（XPS）spectrum of Mo showed that the valence state of Mo changed from Mo⁴⁺to Mo⁶⁺,which was evidence for the promotion of iron ion valence state transformation.In addition,this study found that the composite material had good stability and reusability,and could still achieve high-efficiency degradation of Orange II after 3 cycles of use.In conclusion,this composite system is promising for the treatment of actual environmental water pollutants.（2）Based on the previous research,a Fe Mo₃S₄/r GO composite material was prepared to further reduce the formation of iron sludge in the system.The composite material was used to catalyze the degradation of Orange II by directly activating hydrogen peroxide（H₂O₂）in a Fenton-like system.The results showed that efficient catalytic degradation of Orange II could be achieved by adding only 0.05 mmol H₂O₂,simplifying the experimental process.The removal efficiency of Orange II at a concentration of 20 mg/L could reach nearly 100%within 30 minutes,and the first-order kinetic constant was 0.1603 min^-1,which was 16 times higher than that of traditional Fenton.The addition of the composite material improved the environmental adaptability of the Fenton system,and efficient degradation of various target organic pollutants could be achieved under alkaline conditions with a p H of 11and in complex environmental water conditions.Scanning electron microscopy（SEM）testing revealed that the addition of the r GO carrier effectively prevented the agglomeration of Fe Mo₃S₄,fully exposing their reactive sites and improving the overall catalytic efficiency.Continuous and efficient degradation of Orange II was achieved through dynamic flow filtration experiments,indicating the potential practical application prospects of the composite material.