(1. 中南大學(xué) 冶金科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；
2. 中南大學(xué) 資源加工與生物工程學(xué)院，長(zhǎng)沙 410083；
3. 中南大學(xué) 國(guó)家重金屬污染防治工程技術(shù)研究中心，長(zhǎng)沙 410083)
摘 要: 以啤酒工業(yè)廢棄物麥糟為原料，采用一步快速酯化改性法制備高效重金屬離子吸附劑酯化改性麥糟。研究酯化改性麥糟對(duì)Pb(Ⅱ)的吸附行為、吸附動(dòng)力學(xué)及吸附機(jī)制。結(jié)果表明：在較寬的pH值范圍(4~8)內(nèi)，酯化改性麥糟表現(xiàn)出對(duì)Pb(II)良好的吸附性能。由Langmuir吸附等溫線方程計(jì)算得到該吸附劑對(duì)Pb(Ⅱ)的理論飽和吸附量為393.7 mg/g，高于文獻(xiàn)報(bào)道的大多數(shù)吸附劑的吸附量。吸附反應(yīng)很快在15 min內(nèi)達(dá)到平衡，吸附符合擬二級(jí)動(dòng)力學(xué)方程。活化能的計(jì)算表明吸附為活性化學(xué)吸附。酯化改性麥糟吸附Pb(Ⅱ)主要是羥基和羧基中C—O基團(tuán)的氧原子與Pb(Ⅱ)配合的結(jié)果。
關(guān)鍵字: 酯化改性麥糟；吸附；Pb(Ⅱ)；動(dòng)力學(xué)；吸附機(jī)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
