利用玉米秸秆基生物炭(CSB)负载腐植酸制备腐植酸改性生物炭(CSB-HA)，用于吸附矿区土壤淋溶液中Mn²⁺并分析其吸附特性。借助SEM、BET、XRD、XPS和FT-IR 等方法对制备得到的样品进行表征分析，CSB-HA比表面积为7.911 m²/g，孔隙以介孔居多。优良的孔隙结构提供大量吸附点位，并促进与污染物的接触，使吸附性能提升。CSB-HA表面富含C=O、O=C—O和—COOH等含氧官能团，其中氧原子能与重金属离子进行络合配位形成配位键，从而去除Mn²⁺。CSB-HA对Mn²⁺的最大吸附量为21.493 mg/g，准一级动力学模型、准二级动力学模型、Langmuir等温式和Temkin等温式能较好拟合吸附过程，Temkin常数b<1 kJ/mol，能证明吸附过程存在物理吸附。准二级动力学模型和Langmuir等温式拟合度更高且更接近实际检测值，故吸附过程为单分子层吸附，受物理吸附和化学吸附共同作用，且化学吸附占主导地位。因此含氧官能团种类和质量分数对CSB-HA吸附Mn²⁺产生重要影响。由液膜扩散模型和颗粒内扩散模型分析扩散过程，液膜扩散模型拟合线与纵轴截距较小，因此该过程不是控速阶段。颗粒内扩散模型可拟合为膜扩散阶段(0～60 min)和颗粒内扩散阶段(60～240 min)，后者吸附速率明显降低(k_id1=1.159>k_id2=0.287)，且拟合线均不通过原点，故颗粒内扩散阶段是吸附过程的控速关键阶段。热力学模拟中，分离系数R_L均在0.4～0.6，ΔH=15.41 kJ/mol>0，且ΔG均为负数并随温度升高而减小，表明吸附过程是可逆且自发吸热的，升温能促进吸附反应进行。ΔS=49.90 J/(mol·K)>0，证明吸附过程中固液界面随机性增加。模拟淋溶液吸附实验表明CSB-HA吸附Mn²⁺效果较好且对淋溶液pH有调节作用。

Humic acid modified biochar (CSB-HA) was prepared using corn stover-based biochar (CSB) loaded with humic acid for the adsorption of Mn²⁺ from the soil leachate in the mining area and its adsorption characteristics were analyzed. With the help of SEM, BET, XRD, XPS and FT-IR, the prepared samples were characterized and analyzed. The results show that the specific surface area of CSB-HA is 7.911 m²/g, which is 1.98 times that of CSB, and the pores are mostly mesoporous. The excellent pore structure provides a large number of adsorption sites and promotes the contact with pollutants, so that the adsorption performance is enhanced. The surface of CSB-HA is enriched with the oxygen-containing functional groups such as C=O, O=C—O and —COOH, and the oxygen atoms in the functional groups can be complexed and coordinated with heavy metal ions to form a stable ligand bond, thus removing Mn²⁺. The maximum adsorption of Mn²⁺ by CSB-HA is 21.493 mg/g, and the quasi-primary kinetic model, quasi-secondary kinetic model, Langmuir isotherm and Temkin isotherm can fit the adsorption process well, and the Temkin constant b<1 kJ/mol can prove that the adsorption process Physical adsorption exists. The quasi-secondary kinetic model and Langmuir isotherm fit the adsorption process better and closer to the actual detection value, so the adsorption process is a single molecule layer adsorption, which is subject to the joint action of physical adsorption and chemical adsorption, and the chemical adsorption is dominant. Therefore, the type and mass fraction of oxygen-containing functional groups have an important effect on the adsorption of Mn²⁺ by CSB-HA. The diffusion process was analyzed by the liquid-film diffusion model and the intra-particle diffusion model. The fitted line of the liquid-film diffusion model has a small intercept with the longitudinal axis, so the process is not a velocity-controlled phase. The intra-particle diffusion model can be fitted into a membrane diffusion stage (0−60 min) and an intra-particle diffusion stage (60−240 min), the latter adsorption rate is significantly lower (k_id1=1.159>k_id2=0.287), and the fitted lines do not pass through the origin, so that the intra-particle diffusion stage is the key stage of the adsorption process for controlling the rate. In the thermodynamic simulations, the separation coefficients R_L are in the range of 0.4−0.6, ΔH=15.41 kJ/mol>0, and ΔG is negative and decreases with increasing temperature, indicating that the adsorption process is reversible and spontaneous heat absorption, and the adsorption reaction can be facilitated by warming up. ΔS=49.90 J/(mol·K)>0, which proves that the solid-liquid interface stoichiometry increases during the adsorption process. The simulated adsorption experiments on leaching solution show that CSB-HA has a good adsorption effect on Mn²⁺ and a regulating effect on the pH of leaching solution.