This study rigorously investigated the adsorption behaviors and mechanisms of strontium ions (Sr²⁺) by the pristine and magnetic biochars prepared via the pyrolysis of pristine and FeCl₃-pretreated spent coffee grounds (SCG). The FeCl₃-pretreatment could magnetize successfully the pristine SCG biochars (magnetization value of pristine SCG biochars = 0.19 emu/g; magnetization value of magnetic SCG biochars = 8.99 emu/g) and improved substantially their specific surface area (pristine SCG biochars = 5.3 m²/g; magnetic SCG biochars = 431.7 m²/g) and total pore volume (pristine SCG biochars = 0.002 cm³/g; magnetic SCG biochars = 0.186 cm³/g). However, the removal efficiency of Sr²⁺ with the pristine SCG biochars (33.4–34.1%) was not significantly different from that with the magnetic SCG biochars (33.1–33.9%). The calculated kinetic parameters indicate that the adsorption of Sr²⁺ by the pristine and magnetic SCG biochars was governed by the chemisorption (R² of the pseudo-first-order kinetic equation ≤ 0.602; R² of the pseudo-second-order kinetic equation = 1.000). The higher R² values of the Langmuir isotherm (R² = 0.999) model compared to the Freundlich isotherm model (R² ≤ 0.950) are evident that the monolayer adsorption mainly determined the adsorptive removal of Sr²⁺ with the pristine and magnetic SCG biochars. Moreover, the adsorption of Sr²⁺ using the pristine and magnetic SCG biochars was the spontaneous and endothermic process. These observations indicate that the FeCl₃-pretreatment might offer a viable way to effectively recover the residual SCG biochars after the Sr²⁺ adsorption through the magnetic separation (recovery rate = 90%).

这项研究严格研究了通过原始和FeCl ₃预处理的废咖啡渣（SCG）的热解制备的原始和磁性生物炭对锶离子（Sr ²⁺）的吸附行为和机理。FeCl ₃预处理可以成功地磁化原始SCG生物炭（原始SCG生物炭的磁化值= 0.19 emu / g；磁性SCG生物炭的磁化值= 8.99 emu / g）并显着提高其比表面积（原始SCG生物炭= 5.3）。 m ² / g；磁性SCG生物炭= 431.7 m ² / g）和总孔体积（原始SCG生物炭= 0.002 cm ³ / g；磁性SCG生物炭= 0.186 cm ³/G）。但是，原始SCG生物炭对Sr ²⁺的去除效率（33.4–34.1％）与磁性SCG生物炭对Sr ²⁺的去除效率（33.1–33.9％）没有显着差异。所计算的动力学参数表明，Sr的吸附²⁺由原始和磁性SCG生物炭由化学吸附（R支配²伪一级动力学方程≤0.602; R ²伪二级动力学方程的= 1.000）。越高- [R ^2个Langmuir等温（R值² = 0.999）模型相比，Freundlich等温模型（R ² ≤0.950）是明显的是，单分子层吸附主要是确定的吸附除去锶²⁺与原始和磁性SCG生物炭。此外，使用原始和磁性SCG生物炭吸附Sr ²⁺是自发的和吸热的过程。这些观察结果表明，FeCl ₃预处理可能为通过磁分离吸附Sr ²⁺后有效回收残留SCG生物炭提供了可行的方法（回收率= 90％）。