Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt.
Sci Rep. 2023 Apr 19;13(1):6422. doi: 10.1038/s41598-023-33386-7.
The marine algal biomass of Ulva lactuca was utilized for the extraction of cellulose and the development of cellulose nanocrystals/graphene oxide film. Cellulose nanocrystals with 50-150 nm were produced by HSO hydrolysis of the algal cellulose. The adsorption efficiency of the nanocomposite film for Fe(II) and Fe(III) ions was successfully evaluated using Box-Behnken design. The maximum removal for Fe(II) (64.15%) could be attained at pH 5.13, adsorbent dosage 7.93 g L and Fe(II) concentration 15.39 mg L, while the biosorption of Fe(III) was 69.92% at pH 5.0, adsorbent dosage 2 g L, and Fe(III) concentration 15.0 mg L. However, in the binary system, the removal efficiency of Fe(II) was enhanced to 95.48% at Fe(II):Fe(III) ratio of 1:1, while the Fe(III) removal was increased to 79.17% at ratio 1:2. The pseudo-second-order kinetics exhibited better fitting to the experimental results of Fe(II) and Fe(III) adsorption in both single and binary systems. The intra-particle diffusion was prominent during the biosorption, but the effect of the external mass transfer was significant. The Langmuir, Freundlich, Langmuir-Freundlich, Temkin, and Dubinin-Radushkevich isotherms showed satisfactory fitting to the experimental data, but they differ in priority based on iron state and pH. The adsorption of Fe(II) in the presence of Fe(III) in a mixture was best represented by the extended Langmuir model, while the extended Langmuir-Freundlich model best fitted the adsorption of Fe(III). The FT-IR analysis indicated that physisorption through electrostatic interaction/complexation is the predominant mechanism for the adsorption of iron using the nanocomposite film.
利用浒苔的海洋藻类生物质提取纤维素并制备纤维素纳米晶/氧化石墨烯薄膜。通过 HSO 水解海藻纤维素得到 50-150nm 的纤维素纳米晶。采用 Box-Behnken 设计成功评价了纳米复合材料对 Fe(II)和 Fe(III)离子的吸附效率。在 pH 值为 5.13、吸附剂用量为 7.93g/L 和 Fe(II)浓度为 15.39mg/L 时，最大去除率为 64.15%，而 Fe(III)的吸附率为 69.92%，pH 值为 5.0、吸附剂用量为 2g/L 和 Fe(III)浓度为 15.0mg/L。然而，在二元体系中，当 Fe(II):Fe(III)比为 1:1 时，Fe(II)的去除效率提高到 95.48%，而当 Fe(II):Fe(III)比为 1:2 时，Fe(III)的去除率提高到 79.17%。准二级动力学模型对单、二元体系中 Fe(II)和 Fe(III)吸附的实验结果拟合更好。内扩散在生物吸附过程中很明显，但外扩散的影响也很显著。Langmuir、Freundlich、Langmuir-Freundlich、Temkin 和 Dubinin-Radushkevich 等温线对实验数据拟合较好，但根据铁的状态和 pH 值，它们的优先级不同。在混合体系中存在 Fe(III)时，扩展 Langmuir 模型最能代表 Fe(II)的吸附，而扩展 Langmuir-Freundlich 模型最能代表 Fe(III)的吸附。FT-IR 分析表明，在纳米复合材料吸附铁的过程中，静电相互作用/络合的物理吸附是主要机制。
