Bate Bate, Cao Jingjing, Yang Yixin, Cao Junnan, Zhang Chi, Zhang Shuai
College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310027, China.
Department of Civil Engineering and Construction, Georgia Southern University, Statesboro, GA 30458, USA.
Toxics. 2023 Feb 26;11(3):221. doi: 10.3390/toxics11030221.
In this paper, the adsorption process of copper ions on activated carbon (AC) was simulated in a column test. It was deduced that it is consistent with the pseudo-second-order model. Cation exchange was observed to be the major mechanism of Cu-AC interactions through scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) measurements. Adsorption isotherms were fitted well using the Freundlich model. Adsorption thermodynamics at 298, 308, 318 K demonstrated that the adsorption process is spontaneous and endothermic. Spectral induced polarization (SIP) technique was used to monitor the adsorption process, and the double Cole-Cole model was used to analyze the SIP results. The normalized chargeability was proportional to the adsorbed copper content. Two measured relaxation times from the SIP testing were converted into the average pore sizes of 2, 0.8, 0.6, 100-110, 80-90, and 53-60 µm by the Schwartz equation, which are consistent with the measured pore sizes from both mercury intrusion porosimetry and scanning electron microscopy (SEM). The reduction in the pore sizes by SIP during the flow-through tests suggested that the adsorbed Cu gradually migrated into small pores as with continued permeation of the influent. These results showcased the feasibility of using SIP technique in engineering practice involving the monitoring of copper contamination in land near a mine waste dump or in adjacent permeable reactive barriers.
在本文中，通过柱试验模拟了铜离子在活性炭（AC）上的吸附过程。推导得出该过程符合准二级模型。通过扫描电子显微镜-能量色散X射线光谱（SEM-EDS）、X射线衍射（XRD）和傅里叶变换红外光谱（FTIR）测量观察到阳离子交换是铜-活性炭相互作用的主要机制。用Freundlich模型很好地拟合了吸附等温线。在298、308、318 K下的吸附热力学表明吸附过程是自发的且吸热。采用频谱诱导极化（SIP）技术监测吸附过程，并使用双Cole-Cole模型分析SIP结果。归一化充电率与吸附的铜含量成正比。通过施瓦茨方程将SIP测试中测得的两个弛豫时间转换为平均孔径分别为2、0.8、0.6、100 - 110、80 - 90和53 - 60 µm，这与压汞法和扫描电子显微镜（SEM）测得的孔径一致。在流通试验中，SIP导致的孔径减小表明随着进水的持续渗透，吸附的铜逐渐迁移到小孔中。这些结果展示了在涉及监测矿山废石场附近土地或相邻渗透反应屏障中铜污染的工程实践中使用SIP技术的可行性。
