Su Haize, Qiu Weipeng, Hu Tenggen, Peng Kaibin, Liu Wenfeng, Chen Guilian, Zhao Yali, Xu Zhenlin, Wang Hong, Wen Peng
College of Food Science, Guangdong Provincial Key Laboratory of Food Quality and Safety, South China Agricultural University, Guangzhou 510642, China.
Sericultural Agri-Food Research Institute, Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou 510610, China.
J Hazard Mater. 2024 Dec 5;480:136235. doi: 10.1016/j.jhazmat.2024.136235. Epub 2024 Oct 21.
Efficient and simultaneous removal of anionic and cationic dyes from wastewater using low-cost and environmentally-friendly adsorbent is highly required. Herein, the carboxylated cellulose (carboxyl content: 2.97 mmol/g) derived from pomelo peel was extracted by a one-step HO/HSO-mediated oxidation method. Subsequently, a novel pomelo-peel cellulose/chitosan/sodium alginate (PCS) amphoteric aerogel with a specific core-shell structure was synthesized by multiple physical cross-linking strategies. The shell layer and core layer of the optimized PCS aerogel can selectively adsorb cationic dyes and anionic dyes, in which, the theoretical maximum adsorption capacities were 888.27 mg/g and 1816.87 mg/g towards methylene blue (MB) and Congo red (CR), respectively. Especially, the aerogel's core/shell layer exhibited hierarchical adsorption behavior without overlapping sites even in the binary dye systems. The adsorption performance of obtained amphoteric aerogel remained effective in a wide pH range and under different practical water systems. Moreover, the removal efficiencies for MB and CR were slightly reduced from 90.76 % and 99.66 % to 88.08 % and 91.39 %, respectively, after 5 adsorption-desorption cycles, and the aerogel's structural integrity was also maintained due to its good compressive strength (487.16 KPa). In addition, the adsorption mechanism of PCS aerogel was investigated using adsorption kinetics, isotherm, thermodynamics, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. It was proved that the adsorption process was endothermic spontaneous-monolayer adsorption driven by electrostatic attraction and hydrogen bonding. Therefore, the prepared biobased aerogel was expected to be a prospective material for removing mixed dyes from wastewater.
迫切需要使用低成本且环保的吸附剂高效同时去除废水中的阴离子和阳离子染料。在此，通过一步法HO/HSO介导的氧化方法提取了源自柚子皮的羧化纤维素（羧基含量：2.97 mmol/g）。随后，通过多种物理交联策略合成了一种具有特定核壳结构的新型柚子皮纤维素/壳聚糖/海藻酸钠（PCS）两性气凝胶。优化后的PCS气凝胶的壳层和核层可以选择性地吸附阳离子染料和阴离子染料，其中，对亚甲基蓝（MB）和刚果红（CR）的理论最大吸附容量分别为888.27 mg/g和1816.87 mg/g。特别是，即使在二元染料体系中，气凝胶的核/壳层也表现出分层吸附行为，且无重叠位点。所制备的两性气凝胶在较宽的pH范围内和不同的实际水体系中吸附性能均保持有效。此外，经过5次吸附-解吸循环后，对MB和CR的去除效率分别从90.76%和99.66%略有降低至88.08%和91.39%，并且由于其良好的抗压强度（487.16 KPa），气凝胶的结构完整性也得以保持。此外，利用吸附动力学、等温线、热力学、傅里叶变换红外光谱和X射线光电子能谱研究了PCS气凝胶的吸附机理。结果表明，吸附过程是由静电吸引和氢键驱动的吸热自发单层吸附。因此，所制备的生物基气凝胶有望成为去除废水中混合染料的一种有前景的材料。
