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以甲基丙烯酸丁酯(BMA)和甲基丙烯酸缩水甘油酯(GMA)功能化的纳米SiO2为单体,通过可逆加成-断裂链转移自由基聚合(RAFT)法制备了PBMA/GMA-SiO2有机/无机复合吸附材料,并将其用于吸附含Pb2+的水溶液。考察了吸附时间、温度、pH以及Pb2+初始质量浓度对吸附效果的影响,并对其吸附动力学和热力学特性进行了探讨。结果表明,PBMA/GMA-SiO2对Pb2+具有良好的吸附性能,其对Pb2+的饱和吸附量为423.84mg/g,吸附最佳pH=5~6,平衡时间为1 h,去除率随Pb2+初始质量浓度的减小而增加。优化实验条件下,50 mg吸附剂在298 K时,对pH=6的50 mL 0.02 g/L含Pb2+溶液的去除率高达100%。热力学和动力学过程模拟结果表明,吸附的动力学过程比较符合准二级动力学速率方程,Langmuir等温方程比Freundlich等温方程更适合于描述此吸附行为。颗粒内扩散过程是吸附速率的控制步骤,但不是唯一的速率控制步骤。吸附剂经过5次脱附、吸附后,依然具有较强吸附Pb2+的能力。
PBMA / GMA-SiO2 was prepared by reversible addition-fragmentation chain transfer radical polymerization (RAFT) using nano-SiO2 functionalized with butyl methacrylate (BMA) and glycidyl methacrylate Organic / inorganic composite adsorbent material, and its use for adsorption Pb2 + containing aqueous solution. The effects of adsorption time, temperature, pH and Pb2 + initial concentration on the adsorption were investigated. The adsorption kinetics and thermodynamic properties were also discussed. The results showed that PBMA / GMA-SiO2 had good adsorption properties for Pb2 +, the adsorption capacity of Pb2 + was 423.84mg / g, the optimum pH was 5 ~ 6 and the equilibrium time was 1 h. The removal rate of PBMA / The decrease in concentration increases. Under optimized experimental conditions, removal of 50 mL of 0.02 g / L Pb2 + -containing solution with pH = 6 up to 100% at 298 K was achieved with 50 mg of adsorbent. Thermodynamic and kinetic process simulation results show that the adsorption kinetic process more in line with quasi-second-order kinetic rate equation, Langmuir isotherm equation Freundlich isotherm equation more suitable for describing the adsorption behavior. The intragranular diffusion process is the control step of the adsorption rate but not the only rate control step. Adsorbent after 5 times desorption, after adsorption, still has a strong ability to adsorb Pb2 +.