School of Chemistry and Chemical Engineering, Qinghai Normal University, Xining, Qinghai 810008, China.
Water Sci Technol. 2021 Jul;84(1):251-261. doi: 10.2166/wst.2021.199.
Here adsorption studies were proposed on a carboxylated sludge biochar (CSB) material modified by HNO to assess its capacity in the removal of cobalt from aqueous solution. The as-prepared sludge biochar material was characterized by Brunauer-Emmett-Teller (BET) analysis, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The isotherm process could be well described by the Langmuir isotherm model. The adsorption kinetics indicated that cobalt adsorption followed a pseudo-second-order kinetics model. The mechanism between Co(II) and biochar involved electrostatic interaction, ion exchange, surface complexation and physical function. The adsorption capacity on CSB was as high as 72.27 mg·g, surpassing original sludge biochar (SB) as CSB had abundant oxygen-containing functional groups and many hydroxyls, plus the BET surface areas increased when SB was modified by HNO, which stimulated adsorption effect. Therefore, this work shows that CSB could be used as an efficient adsorbent to remove Co(II) in wastewater.
本研究采用硝酸改性的羧基化污泥生物炭（CSB）材料，评估其从水溶液中去除钴的能力，对吸附性能进行了研究。采用比表面积分析仪（BET）、傅里叶变换红外光谱（FT-IR）、热重分析（TGA）、能谱（EDS）和 X 射线光电子能谱（XPS）对所制备的污泥生物炭材料进行了表征。吸附等温线过程可以很好地用 Langmuir 等温线模型描述。吸附动力学表明，钴的吸附符合准二级动力学模型。Co(II)与生物炭之间的相互作用机制包括静电相互作用、离子交换、表面络合和物理作用。CSB 的吸附容量高达 72.27mg·g-1，明显高于原始污泥生物炭（SB）。这是因为 CSB 具有丰富的含氧官能团和大量的羟基，而且 SB 经 HNO3 改性后，BET 比表面积增加，促进了吸附效果。因此，这项工作表明 CSB 可以作为一种有效的吸附剂，用于去除废水中的 Co(II)。
