复合改性污泥生物炭对 $ Mn^{2+} $ 的吸附研究

针对含锰 $ \left(\mathrm{Mn}^{2+}\right) $废水处理与城市污水处理厂污泥的安全处理处置问题，文章将合肥市某污水处理厂污泥在 $ CO_{2} $气氛和 $ 550^{\circ}C $条件下进行热解，并用3 mol/L KOH进行改性，制备得到复合改性污泥生物炭（composite modified sludge biochar，CMSB），并将其用于含 $ Mn^{2+} $废水处理。实验结果表明，CMSB在pH=4、投加量为1.0 g/L时，对 $ Mn^{2+} $的吸附量可达37.63 mg/g。CMSB对 $ Mn^{2+} $的吸附行为可以很好地通过准二级动力学模型和Langmuir等温线模型拟合，热力学分析结果表明吸附过程是自发、吸热、熵增的，主要吸附机制包括含氧官能团络合、π键作用、静电吸引及阳离子交换。研究结果可为城市污水处理厂污泥的安全处置和含 $ Mn^{2+} $废水处理提供技术支持和理论基础。

Aiming at the problem of the manganese $ \left(\mathrm{Mn}^{2+}\right) $-containing wastewater treatment and the safe treatment and disposal of sludge in municipal sewage treatment plants, the sludge of a sewage treatment plant in Hefei City was pyrolyzed under $ CO_{2} $ atmosphere and $ 550\;^{\circ}C $, and modified with 3 mol/L KOH. Composite modified sludge biochar (CMSB) was prepared and used for the treatment of $ Mn^{2+} $-containing wastewater. The experimental results show that the adsorption capacity of $ Mn^{2+} $ can reach 37.63 mg/g at a pH value of 4 and a dosage of 1.0 g/L of CMSB. The adsorption behavior of $ Mn^{2+} $ by CMSB can be well fitted by the quasi-second-order kinetic model and the Langmuir isotherm model. The thermodynamic analysis results show that the adsorption process is spontaneous, endothermic and entropic. The main adsorption mechanisms include the complexation of oxygen-containing functional groups, $ \pi $-bond, electrostatic attraction and cation exchange. The research results can provide technical support and theoretical basis for the safe disposal of sludge and the treatment of wastewater containing $ Mn^{2+} $ in municipal sewage treatment plants.