摘要

      为了了解分子结构和生物炭类型对土壤中抗生素非生物耗散和结合态的影响，将9种生物炭类型应用于16种抗生素污染的土壤中。在无生物炭的土壤中，抗生素的非生物消散率一般为四环素类（TCs）>磺胺类（SAs）>喹诺酮类（QLs）。这一趋势与抗生素分子结构中氧原子、氮原子和硫原子的总量相当一致。TCs（不含土霉素）和QLs（不含氧氟沙星）的消散趋势与logKow值的顺序正好相反，说明疏水性吸附是其非生物消散的关键。土霉素和氧氟沙星之所以独特，是因为它们分别与其他TCs和QLs相比，又多了一个含O官能团，导致它们的疏水吸附亲和力不同。对于SAs，磺胺嘧啶和磺胺草醚的非生物耗散率分别最高和最低。QLs和TCs是SAs的主要紧密结合组分，分子结构影响SAs的结合组分。在生物炭处理的土壤中，在250℃下产生的生物炭通常对抗生素的非生物消散率有积极影响。在400℃和600℃下产生的生物炭对抗生素非生物消散的影响大小受生物炭类型和抗生素分子结构的影响。生物炭类型对SA结合组分的影响最大，TCs次之，而对QLs的影响最小。生物炭通常会降低抗生素在土壤中的表观分布系数（Kapp），表明添加生物炭后抗生素淋失增加。

      To understand the impacts of molecular structures and biochar types on abiotic dissipation and bound fractions of antibiotics in soil, nine biochar types were applied into a soil contaminated with 16 antibiotics. In soil without biochar, the abiotic dissipation rates of antibiotics were generally tetracyclines (TCs) > sulfonamides (SAs) > quinolones (QLs). The trend was quite consistent with the total amounts of oxygen (O), nitrogen (N) and/or sulphur (S) atoms in antibiotic molecular structures. The dissipation trends of TCs (excluding oxytetracycline) and QLs (excluding ofloxacin) were just opposite the order of their logK_ow values, indicating that hydrophobic adsorption played the key role in their abiotic dissipation. The reason why oxytetracycline and ofloxacin were unique is they had one more O-containing functional group, when compared with the other TCs and QLs, respectively, resulting in their different hydrophobic adsorption affinities. For SAs, sulfadiazine and sulfachinoxalin had the highest and lowest abiotic dissipation rates, respectively. QLs and TCs were the dominant tightly bound fractions, while molecular structures influenced the bound fractions of SAs. In biochar-treated soils, biochars produced at 250 °C generally had a positive effect on the abiotic dissipation rates of antibiotics. The effect sizes of biochars produced at 400 °C and 600 °C for the abiotic dissipation of antibiotics were influenced by both biochar type and antibiotic molecular structure. Biochar type had the strongest impact on SA bound fractions, followed by TCs, while it had minimal influence on QLs. Biochars generally decreased the apparent distribution coefficients (K_app) of antibiotics in soil, indicating an increase in antibiotic leaching following biochar addition.

      https://www.sciencedirect.com/science/article/pii/S0959652620303619