Hydrophilic Iodized X-ray contrast medias (ICM) are difficult to separate from water. Here, a novel porous biochar (MBC) with a high specific surface area (1435.1 m g) was prepared by one-step pyrolysis, which showed excellent adsorption capacity for Iodized X-ray contrast media, including diatrizoic acid (95.1 mg g), iohexol (297.8 mg g), and iopamidol (298.9 mg g). The optimal pyrolysis temperature for MBC was 700 ℃, and the ratio of sodium hydroxide to sodium carbonate was 1:3. Adsorption kinetic was well fitted by the pseudo-second-order model. Adsorption isotherm was best fitted to the Freundlich model. Adsorption thermodynamics suggested that ICM adsorption was spontaneous and endothermic. Material characterizations demonstrated that good adsorption performance of MBC for ICM mainly depended on pore filling, π-π interaction. The density functional theory (DFT) showed that H-bonding between oxygen-containing functional groups on MBC and ICM further promoted adsorption. Recycling experiments showed that MBC had good reusability. The study indicated that one-step pyrolysis synthesis of alkaline substance pretreatment biochar could be a promising adsorbent for water purification.

中文翻译：

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用于高效去除水中碘X射线造影剂的生物质衍生多孔生物炭的制备：吸附性能和潜在机制


亲水性碘化 X 射线造影剂 (ICM) 很难与水分离。在这里，通过一步热解制备了一种具有高比表面积（1435.1 m g）的新型多孔生物炭（MBC），其对碘化 X 射线造影剂（包括泛影酸（95.1 mg g）、碘海醇）表现出优异的吸附能力（297.8 毫克/克）和碘帕醇（298.9 毫克/克）。 MBC的最佳热解温度为700℃，氢氧化钠与碳酸钠的比例为1:3。准二阶模型很好地拟合了吸附动力学。吸附等温线最适合 Freundlich 模型。吸附热力学表明ICM 吸附是自发且吸热的。材料表征表明MBC对ICM的良好吸附性能主要取决于孔填充、π-π相互作用。密度泛函理论（DFT）表明MBC和ICM上的含氧官能团之间的氢键进一步促进了吸附。回收实验表明MBC具有良好的可重复利用性。研究表明，碱性物质预处理生物炭的一步热解合成可能是一种有前景的水净化吸附剂。