Department of Chemistry, Jamia Millia Islamia, New Delhi 110025, India.
Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India.
Environ Res. 2019 Apr;171:328-340. doi: 10.1016/j.envres.2018.11.044. Epub 2018 Nov 30.
Antimicrobial Nigella sativa seed-based nanocomposite, MnO/BC, was synthesized and utilized for the water purification through adsorption, and the photocatalytic degradation. MnO/BC was prepared by co-precipitation method, and characterized using FT-IR, XRD, SEM, TEM, TGA, and DSC techniques. The composite was investigated for inhibition of bacterial cells growth. FT-IR spectrum indicated the presence of oxygenous groups on the surface; TGA and DSC showed thermal degradation; and XRD, SEM, and TEM investigations indicated amorphous, and porous nature of MnO/BC having particle size of 190-220 nm. The nanocomposite inhibited the growth of both Gram-positive and Gram-negative bacteria cells in water. The adsorption of Methylene blue from water was investigated in batch method in terms of amount of MnO/BC, dye concentration, pH, time, and temperature. 1.0 g L of MnO/BC removed more than 98% of Methylene blue from aqueous solution having concentration of 10 mg L and pH 7.0 at 27 °C. The maximum Langmuir adsorption capacity of MnO/BC was 185.185 mg g at 45 °C. The adsorption was an endothermic process which obeyed Freundlich isotherm, and pseudo-second order kinetics. Therefore, the Methylene blue binding onto MnO/BC surface was site-specific partially through the weak hydrogen bonding, and electrostatic interactions. The photocatalytic activity of MnO/BC has been investigated by degrading the Methylene blue molecules/ions in water under the sunlight and 85% of degradation was achieved during 120 min irradiation. The dye was desorbed at lower pH and regenerated MnO/BC was used for second cycle of Methylene blue adsorption. The results obtained for this study are much better than the previous Methylene blue adsorption studies with acid washed Black cumin seeds and MnFeO/BC for which the capacities were 73.529 mg g and 10.070 mg g at 27 °C, respectively (J. Mol. liq. 2018a, 264, 275-284; J. Clean. Prod. 2018a, 200, 996-1008).
基于抗菌黑种草种子的纳米复合材料 MnO/BC 已被合成，并通过吸附和光催化降解用于水净化。MnO/BC 通过共沉淀法制备，并使用 FT-IR、XRD、SEM、TEM、TGA 和 DSC 技术进行了表征。该复合材料用于抑制细菌细胞的生长。FT-IR 光谱表明表面存在含氧基团；TGA 和 DSC 表明热降解；XRD、SEM 和 TEM 研究表明 MnO/BC 具有无定形和多孔性质，粒径为 190-220nm。纳米复合材料抑制了水中革兰氏阳性和革兰氏阴性细菌细胞的生长。通过批量法研究了 MnO/BC 的用量、染料浓度、pH 值、时间和温度对水中亚甲蓝的吸附。在 27°C 时，MnO/BC 去除浓度为 10mg/L、pH 值为 7.0 的水溶液中亚甲蓝的量超过 98%。MnO/BC 的最大 Langmuir 吸附容量为 185.185mg/g，温度为 45°C。吸附是一个吸热过程，符合 Freundlich 等温线和准二级动力学。因此，亚甲蓝与 MnO/BC 表面的结合是通过弱氢键和静电相互作用的部分特异性位点。通过在阳光下降解水中的亚甲蓝分子/离子研究了 MnO/BC 的光催化活性，在 120min 照射期间，85%的染料得到降解。在较低的 pH 值下，染料被解吸，并重新生成 MnO/BC 用于第二次亚甲蓝吸附循环。与酸处理黑种草种子和 MnFeO/BC 的先前亚甲蓝吸附研究相比，本研究的结果要好得多，后者在 27°C 时的容量分别为 73.529mg/g 和 10.070mg/g（J. Mol. liq. 2018a，264，275-284；J. Clean.Prod. 2018a，200，996-1008）。
