摘要
德岛大学安澤幹人首次利用γ-PGA在Fe3O4磁性纳米颗粒上进行涂层,制得了γ-聚谷氨酸-Fe3O4磁性纳米颗粒(PG-M).本实验利用透射电镜以及扫描电镜对PG-M吸附剂的形貌进行了分析,发现PG-M与未涂层的Fe3 O4具有相似的形状以及大小,均为不规则的层状结构,且晶粒直径在120～320 nm之间;实验中针对性地对水溶液中Pb2+进行了吸附探讨.在振荡实验中,通过主要参数的变化(pH值、吸附时间、竞争离子浓度、腐殖酸浓度),得到如下结果:吸附最佳pH值为7.0;吸附量随着吸附时间的延长而增长,吸附平衡时间为45 min;Na+对PG-M去除Pb2+没有很强的干扰性,而Ca2+则显示出一定的干扰作用;腐殖酸对吸附效果的影响是复杂的,表现为先增强吸附效果,随后降低吸附效果;最佳条件时Pb2+的最大吸附量为93.3 mg/g.PG-M对Pb2+的吸附均能较好地符合Freundlich和Langmuir等温吸附模型,其中Langmuir方程能更好地描述PG-M的吸附特征,说明PG-M在水溶液中对金属离子的吸附为单分子层吸附.PG-M吸附符合准二级动力学模型(r2>0.99).不同浓度的HCl和HNO3溶液的再生实验发现,0.1 mol/L的HCl溶液作为吸附再生液,可取得较好的再生效果.表明PG-M是可再生的,具有较好的经济性和可持续性.
In this study,a novel low cost magnetic adsorbent material prepared by poly-γ-glutamic acid（γ-PGA） coating Fe3O4 magnetic particles,which was called coated magnetic namoparticles（PG-M） was developed for the removal of Pb2＋ from water by Dr.Yasuzawa.The particle size of PG-M was about 120-320 nm,and there was no significant difference in Fe3O4 and PG-M particle size,Fe3O4 was only as the support of PG-M core and did not directly involve in the reaction.The shape of PG-M was irregular cubic structure.The experiments were applied to quantify adsorptive time,pH,competitive ion and organics on the removal effect of Pb2＋.The results showed that PG-M was effective in removal of Pb2＋;the equilibrium amount of adsorptive was as high as 93.3 mg/g and the optimized condition of pH value for metal ions removal was 7.0,while contact time was about 45 min.The removal efficiency of Pb2＋ was not significantly influenced by Na＋ while was reduced with the increasing concentration of Ca2＋.The removal of Pb2＋ was enhanced with the presence of organic matter（humic acid,HA） when the concentration of HA was below 5 mg/L,and decreased when the concentration of HA exceeded 5 mg/L.Langmuir isotherms fitted the experimental data better compared to Freundlich isotherms.Pseudo second order model well described the sorption kinetics of Pb2＋.The used PG-M can be desorbed by 0.1mol/L HCl and became reusable.PG-M is nontoxic and eco-friendly,which have a good prospect in water treatment.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2011年第11期3348-3356,共9页
Environmental Science
基金
国家水体污染控制与治理科技重大专项(2008ZX07407-007)
关键词
吸附
Γ-PGA
PG-M
铅离子
离子交换
adsorption
poly-γ-glutamic acid（γ-PGA）
coated magnetic nanoparticles（PG-M）
Pb2＋
ion exchange
