Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi, 110067, India.
Department of Physics, North Eastern Regional Institute of Science and Technology, Nirjuli, Arunachal Pradesh, 791109, India.
Sci Rep. 2017 Aug 9;7(1):7672. doi: 10.1038/s41598-017-03380-x.
L-Cysteine functionalized magnetite nanoparticles (L-Cyst-FeO NPs) were synthesized by chemical co-precipitation using Fe and Fe as iron precursors, sodium hydroxide as a base and L-Cysteine as functionalized agent. The structural and morphological studies were carried out using X-ray powder diffraction, transmission electron microscopy, dynamic light scattering, scanning electron microscopy and energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and UV-Vis spectrophotometric techniques. The zeta potential of bare FeO and functionalized L-Cyst-FeO NPs were +28 mV and -30.2 mV (pH 7.0), respectively. The positive surface charge changes to negative imply the presence of L-Cyst monolayer at particle interface. Band gap energy of 2.12 eV [bare FeONPs] and 1.4 eV [L-Cyst-FeO NPs] were obtained. Lead and chromium removal were investigated at different initial pHs, contact time, temperatures and adsorbate-adsorbent concentrations. Maximum Cr and Pb removal occurred at pH 2.0 and 6.0, respectively. Sorption dynamics data were best described by pseudo-second order rate equation. Pb and Cr sorption equilibrium data were best fitted to Langmuir equation. Langmuir adsorption capacities of 18.8 mg/g (Pb) and 34.5 mg/g (Cr) at 45 °C were obtained. Regeneration of exhausted L-Cyst-FeO NPs and recovery of Pb/Cr were demonstrated using 0.01 M HNO and NaOH. L-Cyst-FeO NPs stability and reusability were also demonstrated.
L-半胱氨酸功能化磁铁矿纳米粒子（L-Cyst-FeO NPs）通过化学共沉淀法合成，使用 Fe 和 Fe 作为铁前体、氢氧化钠作为碱和 L-半胱氨酸作为功能化剂。使用 X 射线粉末衍射、透射电子显微镜、动态光散射、扫描电子显微镜和能量色散 X 射线能谱、傅里叶变换红外光谱和紫外-可见分光光度技术进行结构和形态研究。裸 FeO 和功能化 L-Cyst-FeO NPs 的 ζ 电位分别为+28 mV 和-30.2 mV（pH 7.0）。正表面电荷变为负电荷意味着在颗粒界面处存在 L-Cyst 单层。获得的带隙能分别为 2.12 eV[裸 FeONPs]和 1.4 eV[L-Cyst-FeO NPs]。在不同的初始 pH 值、接触时间、温度和吸附剂-吸附剂浓度下研究了铅和铬的去除。最大 Cr 和 Pb 去除分别发生在 pH 2.0 和 6.0。吸附动力学数据最好由伪二级速率方程描述。Pb 和 Cr 的吸附平衡数据最好拟合 Langmuir 方程。在 45°C 时，Pb（18.8 mg/g）和 Cr（34.5 mg/g）的 Langmuir 吸附容量。通过使用 0.01 M HNO 和 NaOH 证明了耗尽的 L-Cyst-FeO NPs 的再生和 Pb/Cr 的回收。还证明了 L-Cyst-FeO NPs 的稳定性和可重复使用性。
