超声波降解四环素类抗生素废水

Ultrasonic degradation of tetracyclines in aqueous solution

采用超声波降解模拟废水中四环素类抗生素（TCs）：土霉素（OTC）、四环素（TC）和金霉素（CTC），考查废水初始浓度、初始pH、超声波输入功率密度、曝气量和自由基清除剂（正丁醇）对降解效率的影响。结果表明，超声波可以快速高效地降解废水中的TCs，CTC最易被降解，TC和OTC次之；在OTC、TC和CTC初始浓度0．25mg／L，初始pH=8．2，声功率密度1．2W／mL，气水体积比30：1的条件下，超声波辐照20min后去除率分别达到76．8％、84．0％和94．4％。在实验研究条件下，TCs去除率均随初始浓度（0．25～2．00ing／L）的增大而降低，但总去除浓度升高；碱性条件有利于TCs降解，去除率随初始pH（6—11）升高而升高；功率密度（0．24～1．96W／mL）越高，TCs去除率也越高；曝气后TCs的去除率明显升高，随着气水比（10：1～60：1）的增大，去除率逐渐上升；正丁醇有效抑制TCs超声波降解，可推断TCs主要降解途径为自由基氧化。TCs超声波降解过程符合伪一级动力学反应特征。

This study investigated the tetracyclines （ oxytetracycline, OTC ; tetracycline, TC ; chlortetracy- cline, CTC） degradation upon ultrasonic action under different experimental conditions. The effects of initial con- centration （0.25 -2.00 rag/L） ,initial pH（6 - 11 ） of the solution,power density （0.24 -1.96 W/mL） ,aera- tion volume and hydroxyl radical scavenger （normal butanol） were evaluated. It was found that tetracyclines could be degraded rapidly by ultrasonic irradiation,the removal rates were CTC 〉 TC 〉 OTC and CTC was more easily degraded than TC and OTC. When the concentration was 0.25 rag/L, pH was 8.2,power density was 1.2 W/mL and aeration volume was 30 ： 1 [ air/water, （V/V） ] , the removal efficiencies of OTC, TC and CTC were 76.8% 84.0% and 94.4% after 20 min irradiation,respectively. All the impact factors mentioned above had re- marked effects on tetracyclines removal efficiencies,which increased with increasing initial pH, power density and aeration volume,but decreased with increasing concentrations of teracyclines and volumes of normal butanol add- ed. Pseudo-first order reaction model can be used for the fitness of TCs degradation by ultrasonic action.