Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Tianjin 300384, China; School of Civil Engineering, Yantai University, Yantai 264005, China.
Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Tianjin 300384, China.
Carbohydr Polym. 2017 Oct 1;173:28-36. doi: 10.1016/j.carbpol.2017.05.070. Epub 2017 May 26.
Using Fe(III) salts and chitosan, nano iron oxide impregnated in chitosan bead (NIOC) was successfully synthesized for aqueous Cr(VI) detoxification via sol-gel technique without any additional crosslinking agent. NIOC characterization demonstrated that the iron in NIOC mainly existed as nano akaganeite (β-FeOOH) and complex with chitosan. Intraparticle diffusion was the major rate-limiting step. The maximal adsorption capacity was 69.8mg/g (pH 5.0, 20°C). Normal concentration of coexisting anions (SO, CO, SiO-) showed insignificant competition, whereas PO suppressed the Cr(VI) sorption. Cr(VI)-loaded NIOC could be effectively regenerated by alkaline solutions. Column adsorption runs using granular NIOC could effectively treat about 1600 bed volumes of Cr(VI) solution (from 3.7mg Cr/L in influent to <0.5mg Cr/L in effluent). The Cr(VI) removal mechanisms involved the direct sorption of Cr(VI) (electrostatic attraction and ligand exchange), reduction of Cr(VI) into Cr(III) and re-sorption of Cr(III) via chelation on NIOC surface.
采用 Fe(III)盐和壳聚糖，通过溶胶-凝胶技术成功地合成了纳米氧化铁负载于壳聚糖珠（NIOC），用于水中 Cr(VI)解毒，无需任何额外的交联剂。NIOC 的表征表明，NIOC 中的铁主要以纳米纤铁矿（β-FeOOH）的形式存在，并与壳聚糖络合。颗粒内扩散是主要的速率限制步骤。最大吸附容量为 69.8mg/g（pH 5.0，20°C）。共存阴离子（SO、CO、SiO-）的正常浓度几乎没有竞争，而 PO 则抑制 Cr(VI)的吸附。用碱性溶液可以有效地再生负载 Cr(VI)的 NIOC。使用颗粒状 NIOC 的柱吸附运行可以有效地处理约 1600 个床体积的 Cr(VI)溶液（从进水的 3.7mg Cr/L 降至出水的 <0.5mg Cr/L）。Cr(VI)的去除机制涉及 Cr(VI)的直接吸附（静电吸引和配体交换）、Cr(VI)还原为 Cr(III)以及 Cr(III)通过螯合在 NIOC 表面的再吸附。
