MnO_x-coated rice straw biochar was simply synthesized through the reaction of rice straw biochar with KMnO₄ in aqueous solution. SEM-EDS analysis confirmed the successful coating of Mn on the surface of the biochar. XPS and FTIR analyses were carried out to study the possible mechanism of Pb(II) binding onto rice straw (RS) biochar and MnO_x-coated RS biochar. The work focused mainly on the evaluation of the sorbents for Pb(II) binding. Effect of solution pH, agitating time, Pb(II) initial concentration and co-existing Ca(II) ions on Pb(II) binding were examined. Both for RS biochar and MnO_x-coated RS biochar, sorption kinetic data closely follow the pseudo-second-order model. Langmuir isotherm fits well with the experimental data, and the maximum sorption capacity for Pb(II) calculated from Langmuir model were 0.5782 and 1.4732 mmol g⁻¹ for RS biochar and MnO_x-coated RS biochar, respectively. This study suggested that KMnO₄ modification is a simple and effective method to increase the sorption capacity of RS biochar.

通过将稻草生物炭与KMnO ₄在水溶液中反应，可以简单地合成包覆有MnO _x的稻草生物炭。SEM-EDS分析证实了在生物炭表面上成功地涂覆了Mn。进行了XPS和FTIR分析，以研究Pb（II）与稻草（RS）生物炭和MnO _x包覆的RS生物炭结合的可能机理。这项工作主要集中在对Pb（II）结合吸附剂的评估上。考察了溶液pH，搅拌时间，Pb（II）初始浓度和共存Ca（II）离子对Pb（II）结合的影响。用于RS生物炭和MnO _x包被的RS生物炭，吸附动力学数据严格遵循伪二级模型。Langmuir等温线与实验数据非常吻合，根据Langmuir模型计算得出的RS生物炭和MnO _x包覆的RS生物炭的最大Pb（II）吸附容量分别为0.5782和1.4732 mmol g ^-1。这项研究表明，KMnO ₄修饰是提高RS生物炭吸附能力的一种简单有效的方法。