Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Hainan University, Haikou, 570228, China; Centerfor Eco-Environment Restoration Engineering of Hainan Province, Hainan University, Haikou, 570228, China.
National Engineering Laboratory for Improving Quality of Arable Land, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Environ Pollut. 2023 Jun 1;326:121405. doi: 10.1016/j.envpol.2023.121405. Epub 2023 Mar 7.
Efficient environmental remediation of toxic chemicals using effective sorbents has received considerable attention recently. For the present study, the synthesis of a red mud/biochar (RM/BC) composite was performed from rice straw with the aim of achieving Pb(II) removal from wastewater. Characterization was performed by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS), Zeta potential analysis, elemental mapping, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Results showed that RM/BC had higher specific surface area (S = 75.37 m g) than raw biochar (S = 35.38 m g). The Pb(II) removal capacity (q) of RM/BC was 426.84 mg g at pH 5.0, and the adsorption data well fitted pseudo second order kinetics (R = 0.93 and R = 0.98), as well as the Langmuir isotherm model (R = 0.97 and R = 0.98) for both BC and RM/BC. Pb(II) removal was slightly hindered with the increasing strength of co-existing cations (Na, Cu, Fe, Ni, Cd). The increase in temperatures (298 K, 308 K, 318 K) favored Pb(II) removal by RM/BC. Thermodynamic study indicated that Pb(II) adsorption onto BC and RM/BC was spontaneous and primarily governed by chemisorption and surface complexation. A regeneration study revealed the high reusability (>90%) and acceptable stability of RM/BC even after five successive cycles. These findings indicate that RM/BC evidenced special combined characteristics of red mud and biochar, hence its use for Pb removal from wastewater offers a green and environmentally sustainable approach fitting the "waste treating waste" concept.
最近，利用有效吸附剂高效修复有毒化学物质引起了相当大的关注。在本研究中，以稻草为原料合成了赤泥/生物炭（RM/BC）复合材料，旨在实现废水中 Pb(II)的去除。采用 X 射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、能谱（EDS）、Zeta 电位分析、元素映射、扫描电子显微镜（SEM）和透射电子显微镜（TEM）对其进行了表征。结果表明，RM/BC 的比表面积（S=75.37 m²/g）高于原生物炭（S=35.38 m²/g）。在 pH 5.0 时，RM/BC 的 Pb(II)去除容量（q）为 426.84 mg/g，吸附数据很好地拟合了准二级动力学（R²=0.93 和 R²=0.98）以及 BC 和 RM/BC 的 Langmuir 等温线模型（R²=0.97 和 R²=0.98）。随着共存阳离子（Na、Cu、Fe、Ni、Cd）强度的增加，Pb(II)的去除略有受阻。升高温度（298 K、308 K、318 K）有利于 RM/BC 去除 Pb(II)。热力学研究表明，BC 和 RM/BC 上的 Pb(II)吸附是自发的，主要受化学吸附和表面络合控制。再生研究表明，即使经过五次连续循环，RM/BC 的重复利用率（>90%）和稳定性仍然很高。这些发现表明，RM/BC 具有赤泥和生物炭的特殊组合特性，因此其用于从废水中去除 Pb 提供了一种绿色环保且可持续的方法，符合“废物处理废物”的概念。
