改性谷壳生物炭负载磁性Fe去除废水中Pb^(2+)的效果及机制

Effects and mechanisms of magnetic iron supported on rice husk biochar removing Pb^(2+) in wastewater

将谷売生物炭用酸改性后负载磁性Fe_3O_4,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BCTe吸附废水中Pb^(2+)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Pb^(2+)的吸附机理。结果表明对Pb^(2+)的吸附能在2 h内基本达到平衡。在Pb^(2+)溶液初始浓度为100mg·L^(-1),pH=5.0温度为25℃,分別添加0.1g和0.15 g的BC-Fe于50 mL Pb^(2+)溶液中,单位质量的BC-Fe对溶液中Pb^(2+)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;热力学研究表明对Pb^(2+)的吸附过程是自发的吸热过程。

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 Pb^2＋ ions from simulated wastewater,considering such factors as contact time,solution pH,adsorbent dose,initial Pb^2＋ 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 Pb adsorption from wastewater onto BC-Fe.The results showed that the adsorption equilibrium was reached within 2 h.Under the conditions of an initial Pb^2＋ concentration of 100 mg·L^-1,a solution pH of 5.0,and a temperature of 25℃,the Pb^2＋ adsorption capacity and removal ratio achieved using 0.1 g of BC-Fe in 50 mL Pb^2＋ solution were 40.6 mg·g^-1 and 81.3%/respectively.The corresponding values for 0.15 g of BC-Fe were and33.2 mg·g^-1 and 99.9%.The adsorption reaction of Pb^2＋ 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 Pb^2＋ onto BC-Fe was well fitted by the Langmuir adsorption isotherm model,and the thermodynamics data indicated that the adsorption of Pb^2＋ onto BC-Fe was spontaneous and endothermic.