改性谷壳生物炭负载磁性Fe去除废水中Pb2+的效果及机制

将谷壳生物炭用酸改性后负载磁性Fe3O4，得到一种新的吸附材料（BC-Fe）。通过单因素吸附实验，研究了时间、pH、添加量、浓度以及温度等参数对BC-Fe吸附废水中Pb2+的影响，并对其进行比表面积及傅里叶红外光谱分析，探讨该磁性生物炭对Pb2+的吸附机理。结果表明，BC-Fe对Pb2+的吸附能在2 h内基本达到平衡。在Pb2+溶液初始浓度为100 mg·L-1，pH=5.0，温度为25℃，分别添加0.1 g和0.15 g的BC-Fe于50 mL Pb2+溶液中，单位质量的BC-Fe对溶液中Pb2+的吸附量分别为40.6 mg·g-1和33.2 mg·g-1，去除率分别为81.3%和99.9%。该吸附过程符合拟二级动力学模型，理论平衡吸附量为43.9 mg·g-1。用Langmuir等温吸附方程能够很好地描述其吸附行为；热力学研究表明，BC-Fe对Pb2+的吸附过程是自发的吸热过程。

Effects and mechanisms of magnetic iron supported on rice husk biochar removing Pb2+ in wastewater

In this study,rice husk biochar was modified by acid and loaded with magnetic nano-Fe3O4,forming a new adsorbent material (named BC-Fe). A one-factor batch experiment was conducted using BC-Fe to remove Pb2+ ions from simulated wastewater,considering such factors as contact time,solution pH,adsorbent dose,initial Pb2+ concentration,and temperature. Meanwhile,the specific surface area and Fourier transform infrared spectra of BC-Fe were analyzed. The purpose of this study was to investigate the characteristics and mechanisms of Pb2+ adsorption from wastewater onto BC-Fe. The results showed that the adsorption equilibrium was reached within 2 h. Under the conditions of an initial Pb2+ concentration of 100 mg·L-1,a solution pH of 5.0,and a temperature of 25℃,the Pb2+ adsorption capacity and removal ratio achieved using 0.1 g of BC-Fe in 50 mL Pb2+ solution were 40.6 mg·g-1 and 81.3%,respectively. The corresponding values for 0.15 g of BC-Fe were and 33.2 mg·g-1 and 99.9%. The adsorption reaction of Pb2+ onto BC-Fe was well described by quasi-two-level dynamics,and the equilibrium adsorption capacity was 43.9 mg·g-1. The adsorption of Pb2+ onto BC-Fe was well fitted by the Langmuir adsorption isotherm model,and the thermodynamics data indicated that the adsorption of Pb2+ onto BC-Fe was spontaneous and endothermic.