A magnetic adsorbent was prepared by polydopamine coating and thiourea grafting on carbon-modified discarded fly ash magnetic beads (TPCMFA). The successfully preparation of the TPCMFA was supported by SEM image, XRD, FT-IR and Raman spectroscopy. Batch adsorption experiments reveal that the adsorption of silver ions on this magnetic sorbent TPCMFA agreed with the Langmuir isotherm model, with a maximum absorbability of 94.94 mg g^-1. Kinetics data revealed that the adsorption of silver ions on TPCMFA conform to a pseudo-second-order. The TPCMFA achieved remarkable selectivity for Ag (I) that was almost five times higher than that for ions of copper, zinc and nickel. After three cycles, the adsorption capacity of TPCMFA remained at 93.5% of the adsorption capacity of the initial material. These results show that this new magnetic adsorbent prepared from discarded fly ash magnetic beads has promising commercial prospects.

通过聚多巴胺涂层和硫脲接枝到碳改性的废弃粉煤灰磁珠（TPCMFA）上制备磁性吸附剂。TPCMFA的成功制备得到了SEM图像，XRD，FT-IR和拉曼光谱的支持。分批吸附实验表明，该磁性吸附剂TPCMFA上的银离子吸附与Langmuir等温模型一致，最大吸收能力为94.94 mg g ^-1。动力学数据表明，银离子在TPCMFA上的吸附符合伪二级。TPCMFA对Ag（I）的选择性很高，几乎是对铜，锌和镍离子的选择性的五倍。在三个循环之后，TPCMFA的吸附容量保持在初始材料的吸附容量的93.5％。这些结果表明，由废弃的粉煤灰磁珠制备的这种新型磁吸附剂具有广阔的商业前景。