State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
Chemosphere. 2023 Jul;329:138622. doi: 10.1016/j.chemosphere.2023.138622. Epub 2023 Apr 8.
Heavy metals in water are critical global environmental problems. In particular, the anionic heavy metal chromium (Cr) has carcinogenic and genotoxic risks on human health. To this end, an ultralight and flexible nanofibrillated cellulose (NFC)/chitosan (CS) aerogel was developed only by freeze-drying combined with physical thermal cross-linking for efficient one step co-removal of Cr(VI) and Cr(III). The maximum adsorption capacity of Cr(VI) and total Cr calculated according to the Langmuir model was 197.33 and 134.12 mg/g, respectively. Even in the presence of competing soluble organics, anions and oil contaminants, the resulting NFC/CS-5 aerogels showed excellent selectivity. The aerogel exhibited outstanding mechanical integrity, remaining intact after 17 compressions in air and underwater. Meanwhile, after 5 adsorption-desorption cycles, the aerogel was easy to regenerate and maintained a high regeneration efficiency of 80.25%. Importantly, self-assembled NFC/CS-5 aerogel filter connected with the peristaltic pump could purify 752 mL of industrial wastewater with Cr(VI) pre-concentration capacity of 49.71 mg/g. XPS and FT-IR verified that electrostatic interactions, reduction and complexation acted as the main driving forces for the adsorption process. Moreover, such aerogel possessed broad application prospects for alleviating heavy metal pollution in agriculture.
水中的重金属是全球性的环境问题。特别是，阴离子重金属铬（Cr）对人类健康具有致癌和遗传毒性风险。为此，我们通过冷冻干燥结合物理热交联开发了一种超轻、灵活的纳米纤维纤维素（NFC）/壳聚糖（CS）气凝胶，仅需一步即可有效共去除 Cr(VI) 和 Cr(III)。根据 Langmuir 模型计算的 Cr(VI)和总 Cr 的最大吸附容量分别为 197.33 和 134.12 mg/g。即使存在竞争可溶性有机物、阴离子和油污染物，所得的 NFC/CS-5 气凝胶仍表现出优异的选择性。该气凝胶具有出色的机械完整性，在空气中和水下经过 17 次压缩后仍保持完整。同时，经过 5 次吸附-解吸循环后，气凝胶易于再生，再生效率高达 80.25%。重要的是，自组装的 NFC/CS-5 气凝胶过滤器与蠕动泵相连，可净化 752 mL 含有 Cr(VI)的工业废水，其预浓缩能力为 49.71 mg/g。XPS 和 FT-IR 验证了静电相互作用、还原和络合是吸附过程的主要驱动力。此外，这种气凝胶在缓解农业重金属污染方面具有广阔的应用前景。
