Biochars from Chinese medicine material residues and furfural residues at 300–600 °C (MBC300–MBC600 and FBC300–FBC600) were used as adsorbents for removing tetracycline (TC) from water. The influence of pH and co-existing of cations or low molecular weight organic acids (LMWOAs) was investigated on TC adsorption. Further, the bulk biochars were treated by ball milling into sub-micron particles, and their properties and adsorption performance toward TC were also characterized. For pristine biochars, TC adsorption was nonlinear and heterogeneous. Heterogeneity of biochars resulted in multiple sorption mechanisms, including H-bonding, π-π interaction, and pore filling. FBC300 and FBC600 had maximum sorption at pH 5–7. Electrostatic repulsion of positively charged biochar surfaces with TCH₃⁺ at pH < 3 or negatively charged biochar surfaces with TCH⁻ and/or TC²⁻ at pH > 7 was not favorable for TC removal. TC sorption decreased with increasing Na⁺ concentrations from 0 to 0.1 mol/L, and bivalent cations (Ca²⁺ and Mg²⁺) showed greater inhibiting effect relative to monovalent ones (Na⁺ and K⁺). The LMWOAs could combine with co-existing cations, thus reducing the inhibitory effect of cations and improving TC sorption. The ball milling caused remarkable size reduction of biochar particles, thus exposing more active surfaces to capture more TC molecules from water. This study provided low-cost and high-efficiency biochar absorbents to remove antibiotics from water and will benefit for understanding the relationship between TC sorption characteristics/mechanisms and biochar properties.

来自中药残留物和糠醛残留物在300–600°C下的生物炭（MBC300–MBC600和FBC300–FBC600）被用作吸附剂，用于从水中去除四环素（TC）。研究了pH值和阳离子或低分子量有机酸（LMWOA）共存对TC吸附的影响。此外，通过球磨将块状生物炭处理为亚微米颗粒，并对其性质和对TC的吸附性能进行了表征。对于原始生物炭，TC吸附是非线性且非均质的。生物炭的异质性导致多种吸附机制，包括H键，π-π相互作用和孔填充。FBC300和FBC600在pH 5-7时具有最大吸附。带TCH ₃ ⁺的带正电生物炭表面的静电排斥在pH <3或TCH带负电荷的生物炭的表面^-和/或TC ^2-在pH> 7不是为TC去除是有利的。TC的吸附随着Na ⁺浓度从0增加到0.1 mol / L而降低，并且二价阳离子（Ca ²⁺和Mg ²⁺）相对于一价阳离子（Na ⁺和K ⁺）。LMWOA可与共存的阳离子结合，从而降低阳离子的抑制作用并提高TC的吸附。球磨使生物炭颗粒的尺寸显着减小，从而暴露出更多的活性表面以从水中捕获更多的TC分子。这项研究提供了低成本，高效的生物炭吸收剂，用于从水中去除抗生素，并将有助于理解TC吸附特性/机理与生物炭特性之间的关系。