Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
J Hazard Mater. 2020 Dec 5;400:123247. doi: 10.1016/j.jhazmat.2020.123247. Epub 2020 Jun 19.
Solid waste conversion to value-added products is a stepping stone towards sustainable environment. Herein, sesame oil cake (SOC), an oil industry waste was utilized as a precursor to develop hydrochar (HC) samples by varying reaction temperature (150-250 °C) and time span (2-8 h), chemically treated with 10% HO to optimize a sample with maximum yield and Pb(II) adsorption. Highest yield (29.2 %) and Pb(II) (24.57 mg/g at C: 15 mg/L) adsorption was observed on SOCHC@200 °C/6 h, magnetized (mSOCHC@200 °C/6 h) for comparative study. XRD displayed highly crystalline SOCHC@200 °C/6 h and amorphous mSOCHC@200 °C/6 h, both having a characteristic cellulose peak at 14.9°. mSOCHC@200 °C/6 h displayed superparamagnetic behavior with 11.2 emu/g saturation magnetization. IR spectra confirmed the development of samples rich in oxygen containing functionalities; an additional peak for iron oxides appeared at 586 cm in mSOCHC@200°C/6 h spectrum. Four major peaks at 531.9, 399.9, 348.2 and 284.7 eV, assigned to O 1s, N 1s, Ca 2p and C 1s, respectively were observed during XPS analyses. An additional peak at 710.3 eV, ascribed to Fe 2p was observed in mSOCHC@200C/6 h XPS spectrum, while a peak at 143.2 eV for Pb 4f appeared in spectra of both Pb(II) saturated samples. pH dependent (maximum at ∼6.7), exothermic Pb(II) adsorption was found. About 50-70% (at C: 25 mg/L) adsorption on both SOCHC@200 °C/6 h and mSOCHC@200 °C/6 h was accomplished in a minute, attaining equilibrium in 180 and 240 min, respectively. Error functions and superimposed q. and q values supported Langmuir isotherm model applicability, with respective q values of 304.9 and 361.7 mg/g at 25 °C for SOCHC@200 °C/6 h and mSOCHC@200 °C/6 h. Kinetic data was fitted to PSO model. Highest (between 92.2 and 88.9 %) amount of Pb(II) from SOCHC@200 °C/6 h and mSOCHC@200 °C/6 h was eluted by 0.01 M HCl.
固体废物转化为增值产品是迈向可持续环境的重要一步。在此，利用芝麻饼（SOC）作为油工业废物的前体，通过改变反应温度（150-250°C）和时间跨度（2-8 小时），制备了水热炭（HC）样品，并用 10%HO 进行化学处理，以优化最大产率和 Pb（II）吸附的样品。在 SOCHC@200°C/6 h 上观察到最高产率（29.2%）和 Pb（II）吸附（C：15mg/L 时为 24.57mg/g），对其进行了磁处理（mSOCHC@200°C/6 h）进行比较研究。XRD 显示 SOCHC@200°C/6 h 具有高度结晶性和 mSOCHC@200°C/6 h 非晶性，两者在 14.9°处均具有特征纤维素峰。mSOCHC@200°C/6 h 表现出超顺磁性，饱和磁化强度为 11.2emu/g。IR 谱证实了富含含氧官能团的样品的发展；在 mSOCHC@200°C/6 h 光谱中，在 586cm 处出现了氧化铁的附加峰。XPS 分析中观察到四个主要峰，分别为 531.9、399.9、348.2 和 284.7eV，分别对应于 O 1s、N 1s、Ca 2p 和 C 1s。在 mSOCHC@200C/6 h 的 XPS 光谱中观察到另一个位于 710.3eV 的峰，归因于 Fe 2p，而在 Pb（II）饱和样品的光谱中观察到一个位于 143.2eV 的 Pb 4f 峰。发现 pH 值依赖性（在∼6.7 时最大），Pb（II）吸附为放热反应。在 25°C 时，SOCHC@200°C/6 h 和 mSOCHC@200°C/6 h 上分别在 50-70%（C：25mg/L）的范围内完成了吸附，分别在 180 和 240min 内达到平衡。误差函数和叠加的 q 和 q 值支持 Langmuir 等温线模型的适用性，在 25°C 时 SOCHC@200°C/6 h 和 mSOCHC@200°C/6 h 的相应 q 值分别为 304.9 和 361.7mg/g。动力学数据拟合到 PSO 模型。在 0.01M HCl 中，从 SOCHC@200°C/6 h 和 mSOCHC@200°C/6 h 中洗脱的 Pb（II）量最高（92.2%至 88.9%）。
