摘要

由于四环素类抗生素( TCs )的广泛存在，从猪场废水中回收鸟粪石( mgnh4po 4·6H2O )将对农业种植和环境造成TCs药理威胁。研究了猪污水中溶解有机物( DOM )作为污水中的重要介质，对鸟粪石回收过程中TCs迁移的影响。与合成废水固体中TCs浓度为1.49–2.16μg / g相比，DOM的存在显著提高了产物中TCs的含量，其值为360–742μg / g。DOM分馏成具有不同分子量截留即FDOM1（30kDa-0.45μm），FDOM2（5-30kDa），FDOM3（1-5kDa）和FDOM4（<1kDa）的四种大小级分。结果表明，fdom 1和fdom 2的不稳定和聚集是TCs从水相向固体产物迁移的主要原因。同时，fdom 1和fdom 2的某些部分的水解导致含水TCs在各种DOM组分之间重新分配，这就造成了分子量较小的fdom 4对TCs转运有显著影响的假象。pH值从8.5增加到10.5时，沉淀的DOM逐步增加，从而使回收固体中的TCs浓度从94.5μg / g提高到292.4μg / g，达到627.2–825.0μg / g。研究结果有助于更好地了解DOM在磷酸盐回收过程中对TCs迁移和减排的能力。

Due to the extensive existence of tetracyclines (TCs), struvite (MgNH4PO4·6H2O) recovery from swine wastewater will pose TCs-pharmacological threats to the agricultural planting and environment. This study investigated the influences of dissolved organic matters (DOM), as an important medium in the wastewater, on TCs transport during struvite recovery from swine wastewater. Compared to TCs concentrations of 1.49–2.16 μg/g in the solids obtained from synthetic wastewater, the existence of DOM significantly enhanced TCs contents in the products with the values of 360–742 μg/g. DOM was fractionated into four size fractions with different molecular weight cut-off, i.e. FDOM1 (30 kDa-0.45 μm), FDOM2 (5–30 kDa), FDOM3 (1–5 kDa) and FDOM4 (<1 kDa). Results revealed that the destabilization and aggregation of FDOM1 and FDOM2 contributed major roles to TCs transport from the aqueous phase to the solid products. Meanwhile, the hydrolysis of certain parts of FDOM1 and FDOM2 led to the aqueous TCs re-partition among various DOM constituents, which presented a false appearance that FDOM4 with smaller molecular weight posed significant influences on TCs transport. Increasing pH values from 8.5 to 10.5 resulted with a stepwise increase of precipitated DOM, thereby enhancing TCs concentrations from 94.5 to 292.4 μg/g to 627.2–825.0 μg/g in the recovered solids. The outcomes provide a better understanding on the capability of DOM on TCs transport and abatement in the phosphate recovery process.

https://www.sciencedirect.com/science/article/pii/S004313541830109X