RCEES OpenIR  > 环境纳米技术与健康效应重点实验室
Alternative TitleRemoval Mechanisms of Chlortetracycline from Water by Carbon-Based Materials
Thesis Advisor周琴
Degree Grantor中国科学院生态环境研究中心
Place of Conferral北京
Degree Name工学硕士
Degree Discipline环境工程
Keyword金霉素 富钙生物炭 吸附,氮化碳 光催化 Chlortetracycline, Calcium-rich Biochar, Adsorption, Carbon Nitride, Photocatalysis

      抗生素 被 广泛应用于 畜牧业 、 养殖业 和 医疗领域 中, 然而 进入生物体 的 抗生素 70% ~ 90%未能被有效利用而排出体外 。 由于传统水处理方法的局限性,大部分 抗生素 未能被有效降解 或 去除 就 直接排入天然水体中,使其 在环境中 广泛存在 导致了 多种 环境问题 ,同时对人类的健康造成一定威胁 。 因此,如何高效去除水 中抗生素 污染成为一个亟待解决的科学难题。 金霉素是 一种 典型的四环素类抗生素, 属于广谱性抗生素 ,在世界范围内被广泛使用 。 本文 以 金霉素为目标污染物,通过优化一定的实验参数,制备高效吸附剂和催化剂,达到针对性地去除/降解不同浓度金霉素的目的 。主要成果如下:
     (1) 富钙生物炭 吸附剂的制备及对金霉素吸附耦合絮凝 作用的研究针对高浓度金霉素
      点源污染 以天然有机无机杂化材料 螃蟹壳为原材料,在 高温 条件下 裂 解 螃蟹壳 制得 高效吸附剂 富钙生物炭( CRB 并 研究 CRB对 水相中金霉素( CTC)的 去除行为及机制 。 研究 发现, 不同初始浓度 CTC会影响 CRB的等电点和 整个体系 pH,体系 pH会 进一步 影响 CTC的赋存形态和CRB的组成成分 pH下降 会导致 CRB中的钙离子溶出, 从而导致 CRB针对不同浓度的 CTC具有不同的去除效果和机制 CTC初始浓度较低时,仅发生吸附作用 ,在 20分钟内 去除率可 达 90%%,去除机理包括 阳离子 架桥 ,静电相互作用氢键和 π-π相互作用 而 CTC初始浓度较 高 时 去除 机理 主要 包括 离子 架桥和絮凝 作用 。
      (2) 蒙脱石 /石墨相氮化碳 复合材料 可见 光催化降解金霉素的研究
      针对低浓度抗生素残留 污染 ,采用光催化氧化法降解去除。 采用湿法共混共焙烧法制备 成具有高可见光活性的 蒙脱石 /石墨相氮化碳 Mt/g-C3N4 复合材料以 金霉素 为目标污染物 考察 光波长、催化剂投加量、溶解氧和 蒙脱石的引入比例对 光催化降解金霉素 的影响。 结果表明, 可见光条件下, 催化剂投加量 0.1 g/L1%Mt/g-C3N4光照 120 min后 CTC去除 率达 99%,光催化降解过程符合拟一级动力学方程 与原始氮化碳相比降解速率提升 42%。 通过 自由基捕获 实验 证明 •O2-为反应中的主要活性物种,h+和•OH是次要活性物种。此外, 利用高效液相色谱 -飞行时间质谱对降解中间产物进行分析,推测 CTC的可能的降解途径 和机理。
        本研究通过合成富钙生物炭吸附剂,研究了高浓度点源金霉素污染的吸附耦合絮凝去除机理;此外,针对低浓度金霉素污染,利用合成的蒙脱石 石墨相氮化碳复合材料将其光催化降解去除,并研究其降解路径和机理,作为环境友好、廉价和高效稳定的吸附剂 光催化剂材料具有很好的应用前景。

Other Abstract

      Antibiotics are widely used in the prevention and treatment of diseases in humans, livestock and aquatic animals. However, 70%~90% of antibiotics are not effectively used and excreted to the environment. In addition, most of the antibiotics that cannot be metabolized will enter the external environment, causing environmental pollution and threatening human health. Therefore, removing antibiotic pollution in water has become an urgently scientific problem. Chlortetracycline, as one of the typical tetracycline antibiotics and a broad-spectrum antibiotic, widely used in the world. In this paper, chlortetracycline was used as the target pollutant. Optimizing certain experimental parameters, synthesizing high-efficiency adsorbents and catalysts to achieve the purpose of removing/degrading different concentrations of chlortetracycline. The main results are as follows:
      (1) Study on the adsorption coupling with flocculation of chlortetracycline by calcium-rich biochar
      To treat high concentration CTC point source pollution, the high-efficient adsorbent was prepared by pyrolyzing the natural organic and inorganic hybrid material - crab shell under high temperature. The removal behaviors of CRB was examined in details and the mechanism was also investigated. CTC initial concentration would influence the point of zero charge of CRB and the pH of the whole system. The pH would further affect the form of CTC and the composition of CRB. In addition, calcium ion in CRB will dissolute with decreasing of pH. Therefore, for different CTC initial concentration, removal efficiency and removal mechanism varies. In low concentration, CTC could be removed over 90% in 20 min, the removal mechanisms including cation bridging, π-π interaction, electrostatic interaction and hydrogen could be involved. In high concentration of CTC, the removal mechanisms mainly include ion bridging and flocculation bonding.
      (2) Visible-light photocatalytic degradation of chlortetracycline by carbon nitride/montmorillonite composites
      For antibiotic residual pollution, it is recommended to be degraded by photocatalytic oxidation. Montmorillonite/graphite carbon nitride composite (Mt/ g-C3N4) composites with high visible light activity were prepared by wet blending and co-roasting. The effects of montmorillonite on the morphology, photocatalytic activity and photoelectric properties of g-C3N4 were investigated. The optimum mass fraction of montmorillonite in montmorillonite/carbon nitride composite is 1%, and the CTC removal rate is 99% after 120 min of visible light irradiation. The photocatalytic degradation data were fitted well by the pseudo first-order kinetic equation. Compared with the original carbon nitride phase, the degradation rate of montmorillonite/carbon nitride composite increased by 42%. The degradation products were analyzed and the possible degradation pathways of CTC were speculated. In addition, it has been proved by free radical trapping experiments that •O2- is the main active species in the reaction, and h+ and OH are secondary active species.
      In this study, the adsorption coupling with flocculation of high concentration point chlortetracycline and photocatalytic degradation of low concentration chlortetracycline were studied by synthesizing calcium-rich biochar and montmorillonite/carbon nitride composite photocatalyst, respectively. The results suggested that calcium-rich biochar derived from natural crustacean biomass and montmorillonite/carbon nitride composite can be utilized as high efficiency and low-cost material to remove CTC pollution.

Document Type学位论文
Recommended Citation
GB/T 7714
许骐. 典型碳基材料对水体中金霉素的去除机制[D]. 北京. 中国科学院生态环境研究中心,2019.
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