以固相合成法制备Li+掺杂TiO2为吸附剂,对甲基橙模拟废水进行吸附实验,研究甲基橙吸附在Li-TiO2上的动力学和热力学机理。结果表明:在常压和298K下,当pH＝6、甲基橙模拟废水初始浓度20mg/L、Li+掺杂TiO2投加量1.0g/L时,吸附容量18.32mg/g,甲基橙去除率为91.6%。Li-TiO2对甲基橙吸附动力学规律符合Lagergren准一级吸附模型,k1=0.0189min-1,Ea=-5.567kJ/mol。吸附行为服从Langmuir和Freundlich方程,属单分子层吸附。热力学函数 ΔH<0,ΔG<0,ΔS>0,吸附为自发放热过程。可见Li-TiO2是一种去除模拟废水中甲基橙的优良吸附剂。
The adsorption experiment was carried out on simulated wastewater of methyl orange,and Li+-doped TiO2 (Li-TiO2) material prepared by solid phase synthesis as adsorbent.The thermodynamics behavior and kinetics mechanism of methyl orange on Li-TiO2 were studied.The results showed that the adsorption capacity on Li-TiO2(1.0g/L)was up to 18.32mg/g,and the removal rate of methyl orange was up to 91.6% under the condition of 298K,atmospheric pressure,pH 6 and c0 of 20mg/L.Besides,the adsorption dynamics of methyl orange on the apparent of Li-TiO2 fitted the Lagergren Pseudo-first-order model which the adsorption rate constant (k1) and the apparent activation energy (Ea) of methyl orange on Li-TiO2 was 0.0189min-1 and -5.567kJ/mol respectively.It was a monolayer adsorption that the adsorption behavior obeyed the Langmuir and Freundlich equation.Furthermore,thermodynamic data (ΔH<0,ΔG<0 and ΔS>0) illustrated that the adsorption of methyl orange on Li-TiO2 was proved as a spontaneous exothermic process.To sum up,Li-TiO2 was really an excellent adsorbent for removing methyl orange in simulated wastewater.
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