离子印迹吸附微球微流控制备及DFT性能

Microfluidical-synthesis and Quantum Chemistry Insight into Ionic Imprinted Chitosan Adsorbents

为了实现复杂体系重金属废水中目标金属离子的高效选择性去除,基于微流控和离子印迹技术,制备了离子印迹壳聚糖吸附微球,通过批量吸附实验验证和DFT分子模拟佐证的方法,系统研究了吸附微球的吸附特性,探究了目标重金属离子与吸附微球的相互作用机制和靶向结合原理。研究结果表明,离子印迹壳聚糖微球在优化的恒温震荡吸附条件(35℃和160 r/min,Cu离子溶液初始浓度400 mg/L、pH=6)下,可在48 h内到达吸附平衡,对Cu离子的最大吸附容量为117.76 mg/g。此外,吸附速率和等温吸附实验结果符合准二级吸附动力学模型和Langmuir等温吸附模型,证明离子印迹壳聚糖微球对Cu离子的吸附过程是伴随着电子转移的单层化学吸附过程。而基于印迹模板的离子尺度效应和高电负性、以及目标金属离子与吸附微球分子单体间强结合能,能够实现离子印迹壳聚糖吸附微球在二元和(或)三元共存体系中对Cu离子的快速识别捕获和吸附分离。该研究结果可为新型高效吸附微球的研发和性能优化提供理论指导。

In order to selectively remove targeted metal ions from complex metal ions contained wastewater,ionic imprinted chitosan microspheres were synthesized by combining with microfluidics and ion imprinting technologies.Its adsorption performance of as-prepared microspheres were systematically investigated by batch adsorption experiments and DFT molecular simulation to reveal the interaction mechanism and selective binding principle between as-prepared microspheres and targeted Cu ions.The results showed that under the optimized adsorption condition(initial Cu concentration:400 mg/L,pH=6)in a thermostatic shock state(35°C and 160 r/min),the adsorption equilibrium can be achieved within 48 h with the maximum adsorbance of 117.76 mg/g for Cu ions.Besides,the adsorption kinetics and isotherms results were well fitted with pseudo-second order model and Langmuir model,respectively,which demonstrated that the adsorption process was a monolayer chemisorption process accompanied by electron transfer.Moreover,as-prepared microspheres exhibited rapid recognition and selective adsorption property towards targeted Cu ions in binary and/or ternary coexistence systems,which could be attributed to the ionic scale effect and higher electronegativity of Cu ion,as well as the stronger adsorption energy between the targeted Cu ion and the molecular monomers of as-prepared chitosan microspheres.It was concluded that the obtained research achievements could provide theoretical guidance for the development and optimization of new generation biosorbents with high efficiency performance.