| 新型磁性聚谷氨酸吸附剂对水中Pb2+的吸附去除 |
| 摘要点击 3169 全文点击 2069 投稿时间：2010-10-24 修订日期：2011-03-15 |
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| 中文关键词 吸附 γ-PGA PG-M 铅离子 离子交换 |
| 英文关键词 adsorption poly-γ-glutamic acid(γ-PGA) coated magnetic nanoparticles(PG-M) Pb2+ ion exchange |
| DOI 10.13227/j.hjkx.20111131 |
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| 中文摘要 |
| 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Fe3O4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. |
| 英文摘要 |
| 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. |
