Chen Guiling, Yin Yitong, Zhang Xianting, Qian Andong, Pan Xiaoyang, Liu Fei, Li Rui
School of Biological Science, Jining Medical University, No. 669 Xueyuan Road, Donggang District, Rizhao 276826, China.
Molecules. 2024 Apr 18;29(8):1836. doi: 10.3390/molecules29081836.
To develop valuable applications for the invasive weed Palmer amaranth, we utilized it as a novel biochar source and explored its potential for methyl orange adsorption through the synthesis of chitosan-encapsulated Palmer amaranth biochar composite microspheres. Firstly, the prepared microspheres were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy and were demonstrated to have a surface area of 19.6 m/g, a total pore volume of 0.0664 cm/g and an average pore diameter of 10.6 nm. Then, the influences of pH, dosage and salt type and concentration on the adsorption efficiency were systematically investigated alongside the adsorption kinetics, isotherms, and thermodynamics. The results reveal that the highest adsorption capacity of methyl orange was obtained at pH 4.0. The adsorption process was well fitted by a pseudo-second-order kinetic model and the Langmuir isotherm model, and was spontaneous and endothermic. Through the Langmuir model, the maximal adsorption capacities of methyl orange were calculated as 495.0, 537.1 and 554.3 mg/g at 25.0, 35.0 and 45.0 °C, respectively. Subsequently, the adsorption mechanisms were elucidated by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy investigations. It is indicated that electrostatic interactions, hydrogen bonding, π-π interactions and hydrophobic interactions between methyl orange and the composite microspheres were pivotal for the adsorption process. Finally, the regeneration studies demonstrated that after five adsorption-desorption cycles, the microspheres still maintained 93.6% of their initial adsorption capacity for methyl orange. This work not only presents a promising method for mitigating methyl orange pollution but also offers a sustainable approach to managing Palmer amaranth invasion.
为了开发针对入侵杂草糙果苋的有价值应用，我们将其用作新型生物炭源，并通过合成壳聚糖包封的糙果苋生物炭复合微球来探索其对甲基橙的吸附潜力。首先，通过扫描电子显微镜和傅里叶变换红外光谱对制备的微球进行了表征，结果表明其比表面积为19.6 m²/g，总孔体积为0.0664 cm³/g，平均孔径为10.6 nm。然后，系统研究了pH值、用量、盐类型和浓度对吸附效率的影响，以及吸附动力学、等温线和热力学。结果表明，在pH 4.0时获得了甲基橙的最高吸附容量。吸附过程符合准二级动力学模型和朗缪尔等温线模型，是自发的吸热过程。通过朗缪尔模型计算得出，在25.0、35.0和45.0 °C下，甲基橙的最大吸附容量分别为495.0、537.1和554.3 mg/g。随后，通过傅里叶变换红外光谱和X射线光电子能谱研究阐明了吸附机制。结果表明，甲基橙与复合微球之间的静电相互作用、氢键、π-π相互作用和疏水相互作用对吸附过程至关重要。最后，再生研究表明，经过五次吸附-解吸循环后，微球对甲基橙的初始吸附容量仍保持93.6%。这项工作不仅提出了一种减轻甲基橙污染的有前景的方法，还提供了一种管理糙果苋入侵的可持续途径。
