School of Environmental Science and Engineering, Shanghai Jiao Tong University, 200240, China; School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China.
School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China.
Environ Pollut. 2021 Feb 15;271:116312. doi: 10.1016/j.envpol.2020.116312. Epub 2020 Dec 15.
Antibiotics are commonly used in livestock and poultry breeding along with organic arsenic. Through long-term accumulation, they can enter into the surrounding soil through various pathways and contaminate the soil. In this paper, tetracycline antibiotics (TCs) and roxarsone (ROX) contaminated soil were used as the representatives of the two kinds of veterinary drugs contaminated soil, respectively, to study the thermal desorption behavior and arsenic stabilization process. Different parameters like heating temperatures, heat duration, stabilizer type and dosage were optimized for effective removal of TCs and ROX. Furthermore, TCs and ROX removal path and ROX stabilization mechanism were explored. Results of the study showed that over 98% of tetracycline antibiotics and roxarsone were effectively removed at 300 °C for 60 min. The heat treatment process of TCs contaminated soil was controlled by the first-order kinetics. Based on the detection of degradation products and thermogravimetric analysis, the possible thermal degradation path of TCs and ROX was proposed. Addition of FeSO.7HO (10% by weight) as stabilizer during the heat treatment process yielded 96.7% stabilization rate. Through the analysis of arsenic fractions, valence and the characterization of soil samples collected after the heat treatment, mechanism of arsenic stabilization in ROX was explored. The results show that thermal treatment combined with chemical stabilization technology can not only degrade TCs and ROX efficiently and completely, but also convert organic arsenic into inorganic state, which is conducive to better stabilization, and finally achieve effective and safe remediation of this kind of contaminated soil.
抗生素和有机胂经常被用于畜牧业和家禽养殖业。通过长期积累，它们可以通过各种途径进入周围土壤并污染土壤。本文以四环素类抗生素（TCs）和洛克沙胂（ROX）污染土壤为例，分别研究了这两种兽药污染土壤的热解吸行为和砷稳定化过程。优化了不同的参数，如加热温度、加热时间、稳定剂类型和用量，以有效去除 TCs 和 ROX。此外，还探讨了 TCs 和 ROX 的去除途径和 ROX 的稳定化机制。研究结果表明，在 300°C 下加热 60min 可有效去除超过 98%的四环素类抗生素和洛克沙胂。TCs 污染土壤的热解吸过程受一级动力学控制。基于降解产物的检测和热重分析，提出了 TCs 和 ROX 的可能热降解途径。在热解吸过程中添加 FeSO.7HO（10%重量）作为稳定剂，可获得 96.7%的稳定化率。通过对砷形态、价态的分析以及对热解吸后土壤样品的表征，探讨了 ROX 中砷的稳定化机制。结果表明，热解吸联合化学稳定化技术不仅能有效、彻底地降解 TCs 和 ROX，还能将有机砷转化为无机状态，有利于更好地稳定化，最终实现对这类污染土壤的有效、安全修复。
