Ultrasonic Degradation Of Paraben Preservatives In Water

Paraben,a preservative compounds commonly used in human daily life.The extensive use and production in the past century has led to the widespread detection of such compounds in water environments such as natural waters,industrial wastewater and sewage treatment plants.The presence of such compounds in water has greatly threatened human health due to its interference with the human body and other evidences of its toxicity.At present,ultrasonic cavitation is a hot spot for scientists to study,and it has shown satisfactory results in the removal of stable harmful organic pollutants in waters.This paper systematically describes the effects of separate ultrasound on the removal of typical Paraben-Ethylparaben?EtPB?and ultrasonic parameters and other operating parameters under low frequency sonication,and a more in-depth study on the addition.Nano-zero-valent iron?nZVI?and H₂O₂enhance the synergistic effect of the main oxidation factor·OH produced during sonication on sonication.Next,by adding KI and H₂O₂in the ultrasound to produces two different radicals,I·and I₂^-·.in the system.The results showed that the removal of EtPB by ultrasound alone was affected by the initial concentration of pollutants,the ultrasonic power and the pH of the solution.The increase of the initial concentration resulted in the inhibition of the yield of·OH in the solution.The increase in power will enhance the degradation of EtPB.This enhancement may have a“threshold value”;the pH value will affect the presence of EtPB in water.Under acidic conditions,it is more stable and is in a molecular state and reacts in the vicinity of bubbles in water.On the contrary,it reacts in an ionic state at a main solution under alkaline conditions.Therefore,the degradation effect decreases with the gradual increase of pH;inhibition experiments show that·OH is the main substance for removing EtPB in this system,pyrolysis has limited contribution to EtPB.Characterization of nZVI indicates that it is a porous,agglomerated and highly active material.In the case of adding H₂O₂ to the ultrasound simultaneously,the entire system exhibits a synergistic enhancement effect;There is an optimal ratio of the addition amount of H₂O₂ and nZVI;Under neutral conditions,the system has the best removal effect on EtPB;Inhibition experiments show that the system is still the largest contribution of·OH;The optimal ratio of KI and H₂O₂is also present;The best removal effect under acidic conditions;Inhibition experiments show that·OH contributes little in the system,and the presence of HIO intermediates in the system has a possible impact on I·and I₂^-·.This paper provides theoretical guidance for the treatment of parabens in water.