采用吸附等温线和动力学等方法阐明了稻秆生物炭对水体Pb²⁺的吸附特性，并通过元素分析、BET（Brunauer-Emmet-Teller）-N₂比表面积分析、Zeta电位、扫描电镜-能谱仪、傅立叶变换红外光谱、X射线衍射和X射线光电子能谱等分析手段，结合机制贡献比例计算方法，定性和定量地揭示了生物炭吸附机制。结果表明，在不同吸附温度20、30、40 ℃下，生物炭对Pb²⁺的最大吸附量分别为233.48、236.00、237.50 mg/g，均符合Langmuir模型（R² > 0.96），属于单分子层吸附；当初始Pb²⁺浓度为50、100、300 mg/L时，生物炭吸附平衡时间分别为30、90、360 min，均符合准二级动力学模型（R² > 0.95），以化学吸附为主。生物炭对Pb²⁺吸附机制主要包括化学沉淀、离子交换、官能团络合和Cπ电子配位等4种作用，其中化学沉淀产物可能以Pb₄（CO₃）₂（SO₄）（OH）₂和PbCO₃为主，贡献比例为47.15% ~ 50.81%，离子交换主要以Ca²⁺和Mg²⁺为主，贡献比例为32.82% ~ 37.77%，这两者共同贡献比例范围为83.63% ~ 84.92%，其余2种吸附机制共同占比15.03% ~ 16.37%。生物炭对Pb²⁺具有优良的吸附能力，可作为水体中重金属的优势吸附材料之一。

The adsorption characteristics of Pb²⁺ in water by rice-straw biochar were elucidated by adsorption isotherm and kinetics, and the adsorption mechanism of biochar was qualitatively and quantitatively revealed by means of elemental analysis, BET (Brunauer-Emmet-Teller) -N₂ specific surface area analysis, Zeta potential, scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), along with the calculation for relative distribution of each adsorption mechanism. The results indicated that the maximum adsorption capacity of Pb²⁺ by biochar were 233.48 mg/g, 236.00 mg/g and 237.50 mg/g under the temperatures of 20 ℃、30 ℃ and 40 ℃, respectively. The experimental data fitted the Langmuir (R² > 0.96) better than the Freundlich isotherm, which suggested monolayer adsorption and a homogeneous distribution of active surface sites. Under the initial concentrations of 50 mg/L, 100 mg/L and 300 mg/L, the equilibrium time of biochar were 30 min, 90 min and 360 min, respectively, which followed the pseudo-second-order mechanism and corresponded to a chemisorption process. The main mechanisms responsible for Pb²⁺ adsorption by rice-straw biochar included chemical precipitation, cation exchange, Cπ-electron coordination, and functional group complexation, in which the chemical precipitates could be mainly Pb₄ (CO₃)₂ (SO₄) (OH)₂ and PbCO₃, accounting for 47.15% ~ 50.81% of total adsorption. Cation exchange also played an important role in the adsorption mechanisms due to high contribution proportions to total adsorption (32.82% ~ 37.77%). Among the adsorption mechanisms, both the Cπ-electron coordination and functional group complexation could contribute 15.03% to 16.37% to the total adsorption, but these were overshadowed by the chemical precipitation and cation exchange, accounting for 83.63% to 84.92% in the total adsorption. These suggested rice-straw biochar could be an efficient adsorbent for the removal of Pb²⁺ from aqueous solution.