Study On Ultrasonic-Induced Degradation Of Resorcinol In The Solution

The effectiveness of using ultrasonic technology to degrade organic pollutants in wastewater has caught worldwide researchers' attention. Solo ultrasonic irradiation method or the combination method with other treatment methods was recent and potential study field of advanced oxidation technology in water treatment. Nevertheless, most of the work to date has only focused on the sonochemical degradation of monohydrating phenol. Little attention was paid on diphenol. In this dissertation, resorcinol was elected as research object. The influence factors of the ultrasonic degradation effect including ultrasonic intensity, initial concentration of resorcinol, initial pH and species of aerated gas have been investigated. Resorcinol decomposition mechanism and kinetics has been explored. Meanwhile the resorcinol degradation technology of using the ultrasound/hydrogen-peroxide, Fenton reagent and CCl₄ was also investigated.Irradiation time and ultrasound intensity have obviously affected on ultrasound decomposition efficiency of resorcinol. The longer the time of irradiation and the bigger the ultrasound intensity were, the better decomposition result was.The properties including initial concentration of resorcinol, initial pH and species of aerated gas of the solution itself have also affected on ultrasonic decomposition efficiency. The higher the initial concentration was, the smaller the decomposition ratio was, however, the more the total quantity of resorcinol decomposed was. The ultrasonic decomposition ratio with aeration increased to 48.6%, comparing original 31.6% without aeration. The decomposition efficiency was better in the acid solution than the alkaline solution. The initial pH has not obviously affected on ultrasound decomposition efficiency of resorcinol in the acid solution, and the degradation ratio was 35.3% and 31.6% when initial pH was 3.0 and 6.5, respectively.The main mechanism in ultrasonic decomposition of resorcinol was ·OH radicals oxidation reaction, and the decomposition process was consonant with pseudo first-order kinetics. When ultrasonic intensity was 0.2 W·cm^-2 and 0.5W·cm^-2, thereaction rate constant was 3.60 X 10'V1 and 12.38 X lO'V1, respectively.Compared with the ultrasonic irradiation alone, the combination of ultrasonic irradiation and oxidant (hydrogen-peroxide/Fenton reagent) can increase the degradation effect of resorcinol efficiently. Along with more oxidant was added, ultrasonic decomposition ratio became larger. Synergetic effect of ultrasound and Fenton reagent also appeared. When ultrasonic intensity was 0.4W-cm"2 and Fenton reagent dosage was 8mL, the decomposition ratio was 90.3% within 3h. Nevertheless, when only using ultrasound or Fenton reagent, the ratio was 31.6% or 49.6%.The ultrasound decomposition efficiency of resorcinol was also affected by CCU, and with the addition of more CCI4, ultrasonic decomposition ratio became larger. The maximum decomposition ratio was 85.9% under above circumstance.