Yang Chao, Niu Deqing, Zhang Fujie, Zhong Yilong, Cao Tianqi, Li Lei, Liu Yang
School of National Defence Science and Technology, Southwest University of Science and Technology, Mianyang 621010, China.
Southwest Automation Research Institute, Mianyang 621010, China.
Water Sci Technol. 2018 Jun;77(9-10):2454-2462. doi: 10.2166/wst.2018.197.
Hydrous manganese dioxide (HMO) has been synthesized through a facile method. It is found that HMO has an excellent Pb(II) adsorption performance, and an equilibrium adsorption capacity of 127 mg g is expected under room conditions. The sorption capacity is strongly dependent on pH when pH < 7.0, but is not affected by ionic strength, suggesting a mechanism of inner-sphere surface complexation confirmed by X-ray photoelectron analyses (XPS) and Fourier transform infrared spectroscopy (FTIR). The adsorption capacity of Pb(II) in the presence of coexisting negative ions is higher than positive ions. The best fitting of adsorption kinetics and isotherm data are simulated by pseudo-second order equation and Langmuir model, respectively. An endothermic and spontaneous nature in the adsorption process of Pb(II) can be deduced from the obtained thermodynamic data (ΔG < 0, ΔH > 0, ΔS > 0).
通过一种简便的方法合成了水合二氧化锰（HMO）。研究发现，HMO具有优异的Pb（II）吸附性能，在室温条件下预期平衡吸附容量为127 mg/g。当pH < 7.0时，吸附容量强烈依赖于pH，但不受离子强度影响，这表明通过X射线光电子能谱（XPS）和傅里叶变换红外光谱（FTIR）证实的内球表面络合机制。在共存负离子存在下Pb（II）的吸附容量高于正离子。分别用伪二级方程和朗缪尔模型对吸附动力学和等温线数据进行了最佳拟合。根据获得的热力学数据（ΔG < 0，ΔH > 0，ΔS > 0）可以推断出Pb（II）吸附过程具有吸热和自发的性质。
