Preparation and characterization of chitosan–caboxymethyl-β-cyclodextrin entrapped nanozero-valent iron composite for Cu (II) and Cr (IV) removal from wastewater
Preparation and characterization of chitosan–caboxymethyl-β-cyclodextrin entrapped nanozero-valent iron composite for Cu (II) and Cr (IV) removal from wastewater
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DOI：
10.1016/j.cej.2013.09.093
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发表时间：
2014-01
影响因子：
15.1
通讯作者：
Md. Tajuddin Sikder;Yoshihiro Mihara;M. Islam;T. Saito;Shunitz Tanaka;M. Kurasaki
中科院分区：
文献类型：
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作者：
Md. Tajuddin Sikder;Yoshihiro Mihara;M. Islam;T. Saito;Shunitz Tanaka;M. Kurasaki
壳聚糖-羧甲基β-环糊精络合物是一种无毒和可生物降解的稳定剂，将FeO纳米粒子包埋在壳聚糖-羧甲基β-环糊精复合体中，可生成直径2.5m mm、含铁量50%的壳聚糖-FeO纳米粒子-环糊精微珠。铬(VI)和铜(II)的完全消失可能涉及在将Fe0氧化为Fe(III)的同时，将Cr(VI)物理吸附和还原为Cr(III)和Cu(II)为Cu(0)。还原速率可用准二级反应动力学表示。在pH为6时，吸附速率常数随铁负载量和初始浓度的增加而增大，而对铬(VI)和铜(II)的吸附分别为吸热和放热。测得铬(VI)和铜(II)的表观活化能分别为71.99和18.38kJ·−~(-1)。X射线光电子能谱证实了还原过程。吸附平衡数据可用Langmuir等温式和Temkin等温式较好地描述单层吸附和化学吸附过程。通过对颗粒内扩散模型的分析，发现膜扩散和颗粒内扩散都是速度限制步骤。因此，合成的壳聚糖-FeO-纳米颗粒-羧甲基β-环糊精微珠可以作为一种潜在的地表水和地下水现场修复材料。
The entrapment of Fe0nanoparticles within a chitosan–carboxymethyl β-cyclodextrin complex, a nontoxic and biodegradable stabilizer, yields chitosan–Fe0nanoparticle–carboxymethyl β-cyclodextrin beads that are 2.5 mm in diameter and contain 50% iron by weight. The complete disappearance of Cr (VI) and Cu (II) may involve both physical adsorption and reduction of Cr (VI) to Cr (III) and Cu (II) to Cu (0) while oxidizing Fe0to Fe (III). The rate of reduction can be expressed by pseudo-second-order reaction kinetics. The rate constants increased with increasing iron loading and initial concentration at pH 6, while the adsorption of Cr (VI) and Cu (II) was found to be endothermic and exothermic, respectively. The apparent activation energies for Cr (VI) and Cu (II) were found to be 71.99 and 18.38 kJ mol−1, respectively. X-ray photoelectron spectroscopy confirmed the reduction process. The equilibrium data could be well described by both Langmuir and Temkin isotherms for describing monolayer adsorption and chemisorption processes, respectively. Both film diffusion and intraparticle diffusion were found to be the rate-limiting steps from the analysis of an intraparticle diffusion model. Thus, the synthesized chitosan–Fe0-nanoparticle–carboxymethyl β-cyclodextrin beads can be a potential material forin situremediation of contaminated surface and ground water.