Co/C复合材料的制备及其对中性红的吸附性能

Preparation of Co/C composite material and its adsorption performance for neutral red

通过将沸石咪唑盐骨架67(ZIF-67)晶体在不同温度(600、700、800、900和1000℃)的N2气氛中碳化,制得磁性多孔Co/C复合材料,将其用于中性红(NR)的吸附。考察吸附温度、NR初始质量浓度、吸附剂用量及pH等因素对吸附量的影响。结果表明:随着碳化温度的升高,Co/C复合材料比表面积由365 m^(2)/g逐渐减小到111 m^(2)/g;ZIF-67碳化温度为800℃时得到的Co/C的总孔体积最大,达到0.198 cm^(3)/g,且对NR的吸附性能最好,在5 h内达到吸附饱和;溶液温度为30℃、NR初始质量浓度为125 mg/L、吸附剂用量为3 mg、pH=7时得到的最大吸附量为985 mg/g。采用拟二阶方程对吸附动力学数据进行拟合,得到最大吸附量为1013 mg/g,800℃碳化的Co/C吸附NR后在甲醇溶液中脱附再吸附,循环5次后,吸附量维持在最高值的92%以上,且易于通过磁分离而回收。对Co/C复合材料吸附机制的研究表明,Co颗粒与碳材料的协同作用使得Co/C复合材料对NR具有较高吸附量。

Magnetic porous Co/C composites were prepared by carbonization of zeolite imidazolium salt skeleton-67(ZIF-67)crystals in nitrogen atmosphere at different temperatures(600,700,800,900 and 1000℃),which were used for the adsorption of neutral red(NR).The effects of adsorption temperature,initial mass concentration of NR,amount of adsorbent,pH on adsorption capacity were analyzed.Results showed that with the increase of carbonization temperature,the specific surface area of Co/C composites decreased from 365 m^(2)/g to 111 m^(2)/g.When the carbonization temperature of ZIF-67 was 800℃,the total pore volume of Co/C was the largest,reached 0.198 cm^(3)/g,and the NR adsorption performance was the best,reached adsorption saturation within 5 h.The maximum adsorption capacity was 985 mg/g when the solution temperature was 30℃,the initial mass concentration of NR was 125 mg/L,the dosage of adsorbent was 3 mg and pH was 7.The adsorption kinetic data were fitted by pseudo-second-order equation,and the maximum adsorption capacity was 1013 mg/g.Co/C after carbonizing at 800℃adsorbed NR and desorbed in methanol solution and then adsorbed.After 5 cycles,the adsorption capacity was maintained at more than 92%of the maximum value and was easy to be recovered by magnetic separation.The study of the adsorption mechanism showed that Co/C composites had high NR adsorption capacity after the synergistic action of Co particles and carbon materials.