摘要
以硝酸为改性剂,对花生壳进行改性制备吸附剂,用改性花生壳吸附水溶液中的Pb2+,考察了溶液pH值、吸附时间、温度等因素对改性花生壳吸附Pb2+效果的影响。结果表明,当温度为288 K、Pb2+溶液初始浓度为10 mg/L、pH值为5.0时,在改性花生壳用量为4 g/L、吸附时间为60 min的条件下,Pb2+吸附量最大,可达1.69 mg/g。硝酸改性花生壳对Pb2+的吸附符合拟二级动力学方程,颗粒内扩散过程为吸附的主要速率控制步骤。在试验温度下,硝酸改性花生壳对Pb2+的吸附平衡符合Freundlich等温方程,热力学研究表明,吸附焓变ΔH>0,反应吉布斯自由能ΔG<0,表明该吸附过程为自发进行的吸热过程。
Peanut hull was modified by nitric acid and used for absorbing Pb2＋ from water.The influences of pH value,adsorbing time and adsorbing temperature on the adsorption effect of modified peanut hull onto Pb2＋ were discussed.The results indicated that when temperature,initial Pb2＋ concentration,pH value,modified peanut hull amount and absorbing time were 288 k,10 mg/L,5.0,4 g/L and 60 min,respectively,the Pb2＋ absorbing amount reached the highest by 1.69 mg/g.The absorption of nitric acid modified peanut hull onto Pb2＋ met the pseudo-second order kinetic model.The intra-particle diffusion was the main rate control step for adsorption.At the experimental temperatures,the absorption balance of nitric acid modified peanut hull onto Pb2＋ met the Freundlich isotherm equation.The thermodynamic studies showed that the adsorption enthalpy ΔH0,Gibbs free energy ΔG0,which also indicated that this absorbing process is a spontaneous endothermic process.
出处
《湖南农业科学》
2011年第3期44-47,共4页
Hunan Agricultural Sciences
关键词
花生壳
PB2+
吸附
动力学
热力学
peanut hull
Pb2＋
adsorption
kinetics
thermodynamics
