超声-Fenton法对沼液中3种四环素类和3种磺胺类抗生素氧化去除的研究

近年来,各类抗生素被广泛用于畜禽养殖,并经动物代谢后随粪便和尿液排出体外.代谢物通过沼气工程处理后,得到的沼液又多用于灌溉,使得抗生素进入环境被农作物吸收,进而通过食物链的传递对人体产生危害,因此,沼液中抗生素的去除就显得尤为重要.本文选择畜禽养殖中使用较多的6种抗生素作为目标物质,采用超声-Fenton氧化技术进行去除.通过设置单因素实验考察了超声能量密度、H_2O_2浓度、pH值、n(H_2O_2)/n(Fe~(2+))对抗生素去除的影响,并利用响应曲面法研究了各个因素的交互性影响,拟合出去除抗生素的最优条件.结果表明,通过单因素试验筛选出的最佳反应条件为:pH=4,H_2O_2浓度为0.04 mol·L~(-1),n(H_2O_2)/n(Fe~(2+))=10,超声能量密度为0.050 kW·L~(-1),在此条件下四环素、土霉素、金霉素、磺胺甲恶唑、磺胺甲基嘧啶、磺胺嘧啶的去除率分别为91.90%、93.65%、86.09%、87.30%、77.54%、88.21%;再经由响应曲面法进一步优化实验方案得出优化条件为:pH=3.80,H_2O_2浓度为0.04 mol·L~(-1),n(H_2O_2)/n(Fe~(2+))=10.9,超声能量密度为0.055 kW·L~(-1),在此条件下四环素、土霉素、金霉素的去除率分别为92.04%、94.23%、88.46%,磺胺甲恶唑、磺胺甲基嘧啶、磺胺嘧啶的去除率分别为87.98%、80.78%、89.58%,养分TN、TP、TK的保留率分别为99.1%、98.6%、100.2%.可见,超声-Fenton氧化法对沼液中抗生素的去除效果良好,同时又可保留其养分.响应曲面法对优化超声-Fenton氧化去除沼液中的抗生素具有实际应用价值,这为沼液中抗生素的去除提供了一条可能的途径.

Studies on removal of three kinds of tetracycline antibiotics and three kinds of sulfa antibiotics in biogas slurry with ultrasonic-Fenton oxidation

In the past years, various antibiotics have been widely used in livestock and poultry industry, and the unutilized antibiotics may be excreted out from the animal bodies with feces and urine. The excrement is usually treated by the biogas project and then the biogas slurry used for irrigation in China, which leads to the discharge of antibiotics into environment and then absorbed by crops. The transmission of antibiotics into food chain may cause harm to human body. Therefore, the removal of antibiotics in biogas slurry is particularly important. In this paper, three kinds of tetracycline and three kinds of sulfonamide-type antibiotics in biogas slurry were removed through ultrasound-Fenton oxidation technology. The effects of ultrasonic energy density, H₂O₂ concentration, pH and molar ratio n(H₂O₂)/n(Fe²⁺) on antibiotic removal were investigated by single-factor experiments. The interaction among different factors and the optimal condition for removal were studied using the response surface method. The results show that, under the condition of pH=4, 0.04 mol·L^-1 of H₂O₂, n(H₂O₂)/n(Fe²⁺)=10, and 0.050 kW·L^-1 of ultrasonic energy density, the removal rate for tetracycline, oxytetracycline, chlorotetracycline, sulfamethoxazole, sulfamethazine and sulfadiazine was 91.90%, 93.65%, 86.09%, 87.30%, 77.54% and 88.21%, respectively. RSM analysis shows that under the optimal condition of pH=3.80, 0.04 mol·L^-1 of H₂O₂ concentration, n(H₂O₂)/n(Fe²⁺)=10.9, and 0.055 kW·L^-1 of ultrasonic energy density, the removal rate was 92.04%, 94.23% and 88.46% for tetracycline, oxytetracycline and chlorotetracycline, and 87.98%, 80.78% and 89.58% for sulfamethoxazole, sulfamethazine and sulfadiazine, respectively. The retention rate of nutrient TN, TP and TK was 99.1%, 98.6% and 100.2%, respectively. Our results indicate that the ultrasonic-Fenton oxidation is a good method for the removal of antibiotics in biogas slurry while ensuring the retention of nutrients. The response surface method has a practical application value for the optimization of the ultrasonic-Fenton oxidation for the removal of antibiotics in biogas slurry.