Dou Detian, Wei Donglai, Guan Xin, Liang Zhenjiang, Lan Lihong, Lan Xiongdiao, Liu Pengru, Mo Huiqun, Lan Ping
Guangxi University for Nationalities, Guangxi Key Laboratory for Polysaccharide Materials and Modifications, Key Laboratory of New Technology for Chemical and Biological Transformation Process of Guangxi Higher Education Institutes, Nanning 530006, China; Guangdong Provincial Key of New and Renewable Energy Research and Development, Guangzhou 510640, China.
Guangxi University for Nationalities, Guangxi Key Laboratory for Polysaccharide Materials and Modifications, Key Laboratory of New Technology for Chemical and Biological Transformation Process of Guangxi Higher Education Institutes, Nanning 530006, China.
J Hazard Mater. 2022 Feb 5;423(Pt B):127137. doi: 10.1016/j.jhazmat.2021.127137. Epub 2021 Sep 10.
Most natural polymers exhibit limited functional groups, which is not favourable for the adsorption of various ions and their utilisation. To overcome this drawback, a novel in-situ-doped nano-calcium carbonate (CaCO) chitin hydrogel was synthesised as an efficient adsorbent for Cu (II) and Cd (II) ions. Scanning electron microscopy and Brunauer-Emmett-Teller results revealed that the synthesised CaCO/chitin hydrogel exhibited loose macropores and mesopores. Subsequently, Fourier transform infrared, Raman, and X-ray diffraction characterisation characterisation proved that chitin was successfully doped with nano-CaCO. The mechanical properties of CaCO/chitin hydrogel were superior to those of the unmodified chitin hydrogel and could efficiently adsorb Cu (II) and Cd (II) ions in water. The effect of pH, initial concentration, adsorbent dosage, and temperature was assessed to determine the adsorption properties of the hydrogel. Under suitable experimental conditions, the maximum adsorption rate of the CaCO/chitin hydrogel was approximately 96%. The time-dependent adsorption kinetics followed a quasi-second order model, and the adsorption process followed the Langmuir model. The maximum adsorption capacities of Cu (II) and Cd (II) according to the Langmuir curve were 194.61 and 191.58 mg/g, respectively. Compared with the binary competitive system, the material exhibited a specific selectivity to the adsorption of Cu (II). X-ray photoelectron spectroscopy (XPS) revealed that nitrogen and oxygen atoms were involved in chelation with the metal ions. The successful compounding of calcium carbonate nanoparticles provided more active adsorption sites for the gel. The novel material exhibited excellent adsorption effects on Cu (II) and Cd (II) ions when applied to a water sample. Thus, the novel material exhibits excellent potential for application. The Cu (II) and Cd (II)ion removal efficiencies after five successive adsorption cycles were higher than 90%, which indicated that the composite material exhibited excellent stability and reproducibility.
大多数天然聚合物的官能团有限，这不利于各种离子的吸附及其利用。为克服这一缺点，合成了一种新型的原位掺杂纳米碳酸钙（CaCO₃）几丁质水凝胶，作为一种高效吸附剂用于吸附铜（II）和镉（II）离子。扫描电子显微镜和布鲁诺尔-埃米特-泰勒结果表明，合成的CaCO₃/几丁质水凝胶呈现出疏松的大孔和中孔。随后，傅里叶变换红外光谱、拉曼光谱和X射线衍射表征证明几丁质成功掺杂了纳米CaCO₃。CaCO₃/几丁质水凝胶的力学性能优于未改性的几丁质水凝胶，并且能够有效吸附水中的铜（II）和镉（II）离子。评估了pH值、初始浓度、吸附剂用量和温度的影响，以确定水凝胶的吸附性能。在合适的实验条件下，CaCO₃/几丁质水凝胶的最大吸附率约为96%。时间依赖性吸附动力学遵循准二级模型，吸附过程遵循朗缪尔模型。根据朗缪尔曲线，铜（II）和镉（II）的最大吸附容量分别为194.61和191.58 mg/g。与二元竞争体系相比，该材料对铜（II）的吸附具有特定选择性。X射线光电子能谱（XPS）表明，氮和氧原子参与了与金属离子的螯合。碳酸钙纳米颗粒的成功复合为凝胶提供了更多的活性吸附位点。该新型材料应用于水样时，对铜（II）和镉（II）离子表现出优异的吸附效果。因此，该新型材料具有优异的应用潜力。连续五次吸附循环后，铜（II）和镉（II）离子的去除效率高于90%，这表明该复合材料具有优异的稳定性和可重复性。
