(1. 中南大学 冶金科学与工程学院，长沙 410083；
2. 中南大学 资源加工与生物工程学院，长沙 410083；
3. 中南大学 国家重金属污染防治工程技术研究中心，长沙 410083)
摘 要: 以啤酒工业废弃物麦糟为原料，采用一步快速酯化改性法制备高效重金属离子吸附剂酯化改性麦糟。研究酯化改性麦糟对Pb(Ⅱ)的吸附行为、吸附动力学及吸附机制。结果表明：在较宽的pH值范围(4~8)内，酯化改性麦糟表现出对Pb(II)良好的吸附性能。由Langmuir吸附等温线方程计算得到该吸附剂对Pb(Ⅱ)的理论饱和吸附量为393.7 mg/g，高于文献报道的大多数吸附剂的吸附量。吸附反应很快在15 min内达到平衡，吸附符合拟二级动力学方程。活化能的计算表明吸附为活性化学吸附。酯化改性麦糟吸附Pb(Ⅱ)主要是羟基和羧基中C—O基团的氧原子与Pb(Ⅱ)配合的结果。
关键字: 酯化改性麦糟；吸附；Pb(Ⅱ)；动力学；吸附机制
（1. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China;
2. School of Minerals Processing and Bioengineering, Central South University, Changsha 41008）
Abstract:Spent grain, a by-product of brewing industry, was used to prepare an efficient heavy metal adsorbent using one-step and fast esterification method. The adsorption behaviors, adsorption kinetics and mechanism of Pb(Ⅱ) by esterified spent grain (ESG) were investigated. The results show that the esterified spent grain exhibited good adsorption performance over the wide pH range of 4-8. The maximum theoretical Pb(Ⅱ) adsorption capacity of ESG calculated from Langmuir isotherm is 393.7 mg/g, which is higher than that of other adsorbents reported. The sorption process is very fast and the equilibrium is established in 15 min. The sorption kinetics is well described by the pseudo-second order kinetic model. The calculated activation energy (Ea) implies that adsorption of Pb(Ⅱ) on ESG is a chemical adsorption. Fourier transform infrared spectroscopy (FTIR) analysis demonstrates that the oxygen atoms of hydroxyl group and the carbon-oxygen (C—O) in carboxyl group of ESG complexing with Pb(Ⅱ) leads to the adsorption.
Key words: esterified spent grain; adsorption; Pb(Ⅱ); kinetics; adsorption mechanisms
