Degradation of antibiotic sulfamethoxazole by biochar-activated persulfate: Factors affecting the activation and degradation processes
Degradation of antibiotic sulfamethoxazole by biochar-activated persulfate: Factors affecting the activation and degradation processes
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DOI：
10.1016/j.cattod.2017.12.028
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发表时间：
2018-09-01
期刊：
影响因子：
5.3
通讯作者：
Mantzavinos, Dionissios
中科院分区：
文献类型：
--
作者：
Kemmou, Liana;Frontistis, Zacharias;Mantzavinos, Dionissios
以废麦芽根状物为原料，制备水处理用生物炭。特别是，测试了生物炭(BC)活化过硫酸钠(SPS)氧化磺胺甲恶唑(SMX)的能力，磺胺甲恶唑(SMX)是新兴微污染物家族中的一种代表性抗生素。采用氮气吸附、傅立叶红外光谱、扫描电子显微镜、X射线衍射仪、热重分析和电位质量滴定等手段对生物炭进行了表征，结果表明，生物炭的比表面积为100m(2)/g，零电荷点为8.4，其表面含有大量的羟基，其中羟基可能为酚类结构。考察了不同的工艺参数，如SPS浓度(100~600 mg/L)、SMX浓度(125~500mU/L)和水基质(纯水、瓶装水、生活污水处理、醇类自由基清除剂和腐植酸)对降解的影响。基质对降解的实际影响很小，自由基清除剂的影响也很小。根据PMT曲线，过硫酸盐似乎通过与表面官能团的相互作用在生物炭表面发生活化，生成不在溶液中释放的自由基；这一机制被腐植酸的存在所促进。生物炭诱导的SPS活化也与20 kHz超声波或模拟太阳光耦合。在任何一种情况下，组合活化比单独活化更有效，导致过程协同；基于准一级速率常数，协同程度为23-35%。
Spent malt rootlets were valorized to synthesize biochars for water treatment. In particular, the ability of biochar (BC) to activate sodium persulfate (SPS) for the oxidation of sulfamethoxazole (SMX), a representative antibiotic belonging to the family of emerging micro-contaminants, was tested. The biochar was fully characterized by nitrogen adsorption, FTIR spectroscopy, SEM, XRD, TGA and potentiometric mass titration (PMT); the biochar has a specific surface area of 100 m(2)/g, a point of zero charge value of 8.4 and its surface contains, amongst others, a considerable amount of hydroxyl groups probably in phenolic structure.The effect of various parameters such as SPS concentration (100-600 mg/L), SMX concentration (125-500 mu g/L) and the water matrix (pure water, bottled water, treated domestic wastewater, alcohols as radical scavengers and humic acid) on degradation was investigated. The actual matrix effect on degradation was minor and so was the effect of radical scavengers. Based on the PMT curves, persulfate activation seems to occur on the biochar surface through interactions with the surface functional groups, generating radicals that are not released in the solution; this mechanism is promoted by the presence of humic acid.The biochar-induced SPS activation was also coupled with either 20 kHz ultrasound irradiation or simulated solar light. In either case, the combined activation was more efficient than the individual ones, leading to process synergy; the degree of synergy, based on pseudo-first order rate constants, was 23-35%.