| Fe@GOCS的制备及其对水中As(Ⅲ)的吸附 |
| 摘要点击 1720 全文点击 552 投稿时间：2020-01-20 修订日期：2020-02-21 |
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| 中文关键词 氧化石墨烯 壳聚糖 吸附 As(Ⅲ) 铁 |
| 英文关键词 graphene oxide chitosan adsorption As(Ⅲ) iron |
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| 中文摘要 |
| 基于自组装原理混合了氧化石墨烯、壳聚糖和FeCl3·6H2O，并使用NaOH溶液固定，戊二醛-甲醇溶液交联后得到了不同载铁量的载铁氧化石墨烯壳聚糖（Fe@GOCS）球形材料，采用静态吸附实验研究其对水溶液中As（Ⅲ）的吸附去除及机制.结果表明，吸附剂负载的铁以α-FeO（OH）形态为主，对As（Ⅲ）的吸附容量随pH的降低呈上升趋势，实验最佳pH值为3.在温度298.15、308.15和318.15 K且pH值为3条件下，As（Ⅲ）的吸附反应在45 h左右达到平衡，吸附剂最佳投加量为1.0 g·L-1，最大吸附容量可达289.4 mg·g-1.5次吸附-解吸附后，吸附容量未下降，反而呈上升趋势.热力学结果显示：ΔGθ<0、ΔSθ > 0和ΔHθ > 0，表明Fe@GOCS对As（Ⅲ）的吸附过程是吸热和熵增的自发反应，升温利于吸附；吸附过程符合伪二级动力学方程，Freundlich和Sips等温吸附模型能更好地描述对As（Ⅲ）的吸附行为.结合材料表征测试结果，认为离子交换和表面络合是Fe@GOCS去除As（Ⅲ）的主要机制. |
| 英文摘要 |
| Based on the principle of self-assembly, graphene oxide, chitosan, and FeCl3·6H2O were mixed to prepare graphene oxide-chitosan coated iron-composite particles (Fe@ GOCS). Batch static experiments were carried out to investigate the kinetic and thermodynamic characteristics of As(Ⅲ) adsorption, and to identify the adsorption mechanism. Results showed that the iron on the GOCS was mainly in the form of α-FeO(OH). The As(Ⅲ) adsorption capacity increased with decreasing pH, and the highest adsorption capacity occurred at pH 3. After approximately 45 h, As(Ⅲ) adsorption reached equilibrium under the conditions of pH 3 and a temperature of 298.15, 308.15, and 318.15 K. The maximum adsorption capacity was 289.4 mg·g-1 for an optimal dosage of adsorbents of 1.0 g·L-1. After five times of repeated adsorption-desorption, the adsorption capacity increased slightly. The thermodynamic parameters showed that ΔGθ<0, ΔSθ > 0, and ΔHθ>0, thus indicating that As(Ⅲ) adsorption on Fe@GOCS was a spontaneous, endothermic, and entropy-increasing reaction, and that a higher temperature was more favorable for As(Ⅲ) adsorption. The pseudo-second-order model provided a good fit of the As(Ⅲ) adsorption kinetics for Fe@GOCS. Compared to the Langmuir isotherm, As(Ⅲ) adsorption experimental data fitted better to the Freundlich and Sips models. In combination with the characterization results, it was found that ion exchange and surface complexation were the main mechanisms of As(Ⅲ) removal from aqueous solution using Fe@GOCS. |
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