For antibiotic-enriched waste activated sludge, classical iron-based chemical conditioning significantly enhanced sludge dewaterability. Nevertheless, the intricate constituents within sludge rapidly depleted reactive oxygen species (ROS), leading to challenges such as excessive production of iron sludge and inadequate elimination of antibiotics from sludge. Herein, we proposed an innovative strategy integrating biochar with Fe(II) for peroxymonosulfate (PMS) activation, aiming to enhance both sludge dewaterability and antibiotics elimination simultaneously. Compared to classical chemical conditioning of Fe(II)/PMS, the presence of biochar not only reduced bound water content of sludge from 1.36 g/g DS to 0.97 g/g DS, but also enhanced sulfamethoxazole (SMX) degradation rate constant from 0.015 min^-1 to 0.042 min^-1. Mechanism studies disclosed the essential roles of biochar in modulating Fe oxidative states distribution and reaction sites in multiphase. Initially, biochar elevated Fe(II)/Fe(III) ratio from 0.38 to 0.78 by abundant carbon defects, which significantly promoted the cumulative concentration of predominant ROS, hydroxyl radicals (•OH), from 4.6 mM to 8.1 mM. Subsequently, EPS underwent destruction by •OH, leading to the liberation of antibiotics and negatively charged polysaccharides (PS), proteins (PN). Secondly, biochar enriched hydrophobic PN with an elevated ratio of PN/PS from 0.92 to 1.50, while the charge neutralization occurred between Fe(II)/Fe(III) and PN, PS, leading to sludge particles granulation. Finally, the mesoporous structure of biochar not only achieved SMX enrichment, but also enhanced the mass transfer of Fe(II)/Fe(III) from sludge aqueous phase to its surface, ensuring that the in-situ generated •OH efficiently targets the locally concentrated SMX. Overall, this work provides a new guidance for developing biochar-mediated chemical conditioning, aiming to enhance the generation and utilization of •OH for antibiotics elimination from sludge.

中文翻译：

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通过调节多相中 Fe 氧化态分布和反应位点，在生物炭介导的化学调节中增强污泥脱水性和限制抗生素降解


对于富含抗生素的废弃活性污泥，经典的铁基化学调节显著提高了污泥脱水能力。然而，污泥中错综复杂的成分会迅速耗尽活性氧 （ROS），从而导致铁污泥过量生产和污泥中抗生素去除不足等挑战。在此，我们提出了一种将生物炭与 Fe（II） 相结合用于过氧一硫酸盐 （PMS） 活化的创新策略，旨在同时提高污泥脱水性和抗生素消除。与 Fe（II）/PMS 的经典化学处理相比，生物炭的存在不仅将污泥的结合水含量从 1.36 g/g DS 降低到 0.97 g/g DS，而且还将磺胺甲噁唑 （SMX） 降解速率常数从 0.015 ^min-1 提高到 0.042 ^min-1。机制研究揭示了生物炭在调节多相 Fe 氧化态分布和反应位点中的重要作用。最初，生物炭通过丰富的碳缺陷将 Fe（II）/Fe（III） 比值从 0.38 提高到 0.78，这显着促进了主要 ROS、羟基自由基 （•OH） 的累积浓度从 4.6 mM 提高到 8.1 mM。随后，EPS 被 •OH 破坏，导致抗生素和带负电荷的多糖 （PS） 和蛋白质 （PN） 的释放。其次，富含生物炭的疏水性 PN 的 PN/PS 比值从 0.92 提高到 1.50，而电荷中和发生在 Fe（II）/Fe（III） 和 PN、PS 之间，导致污泥颗粒造粒。 最后，生物炭的介孔结构不仅实现了 SMX 富集，还增强了 Fe（II）/Fe（III） 从污泥水相到其表面的传质，保证了原位生成的•OH 有效地靶向局部浓缩的 SMX。综上所述，本研究为开发生物炭介导的化学调理提供了新的指导，旨在提高 •OH 的产生和利用，以消除污泥中的抗生素。