School of Environmental and Municipal Engineering, Lanzhou Jiaotong University
State Key Laboratory of Water Resource Protection and Utilization in Coal Mining, National Institute of Clean and Low Carbon Energy
China Coal Society
Technical Centre for Soil, Agriculture and Rural Ecology and Environment, Ministry of Ecology and Environment

矿井水中（F−）超标已成为制约我国西部矿区煤炭绿色开发的主要挑战之一。针对该问题，开发了机械化学法一步固相反应制备Al改性活性炭（AC-Al）的方法，解决了常规水热法改性活性炭产生废液废渣、制备周期长的问题，并实现了矿井水中F−的快速、高效去除。研究了Al添加量、pH、共存阴离子和有机物、吸附剂投加量及反应时间等对除氟性能的影响。AC-Al除氟性能与Al添加量成正比，添加量为0.32 g，吸附反应30 s时，水中F−去除率达到80%以上。pH在3~10范围内，F−去除率均大于80%，具有良好的水质适应性。吸附过程更符合Langmuir模型，即为单层吸附，理论饱和吸附量为1.47 mg/g。吸附过程符合准一级动力学模型。硫酸根离子、氯离子和碳酸氢根离子（1 000 mg/L时）、腐殖酸对F−去除没有影响，氯离子和碳酸氢根离子质量浓度为3 000 mg/L时，除氟率分别降低约21%和11%。AC-Al投加量为10 g/L时，矿井水中F−去除率达84.9%（30 s内），质量浓度从4.85 mg/L降低至0.73 mg/L，满足《地表水环境质量标准》（GB3838—2002）中F−浓度限值（I、II、III类），矿井水中F−吸附过程同样符合准一级动力学模型。元素面分布表明，Al均匀地负载于活性炭表面；F−均匀吸附在AC-Al上，与Al分布特征相似，证明Al是F−吸附潜在活性位点。X射线光电子能谱结果表明，F−吸附前后，AC-Al表面的Al元素结合能从74.20 eV升高至74.28、77.80 eV等2种状态，说明Al与F结合形成了Al-FOH、Al-F化学键，是快速稳定除氟的直接原因。同时，AC-Al吸附剂上的Al溶出量很低（0.34 μg/g）。机械化学法制备的Al改性活性炭除氟效果良好，可为除氟吸附剂制备提供新的普适性技术路径，同时为解决矿井水除氟问题提供技术支撑。

High fluoride (F−) level in coal mining water has became one of the major challenges which restricts the green development of coal mining in western China. To resolve this problem, a mechanochemical one-step solid phase reaction method for preparing aluminum modified activated carbon (AC-Al) was developed, which avoid production of liquid and solid waste as well as long preparation period compared with conventional hydrothermal modification methods, as a result, fluoride was removed from coal mining water fast and efficiently. The effects of Al addition amount, pH, coexisting anions and organics, adsorbent dosage and reaction time on the fluorine removal capability were studied. The fluoride removal efficiency of AC-Al was proportional to the addition amount of Al, and when Al addition amount was 0.32 g, the fluoride removal from simulated water reaches >80% within 30 s. Over 80% of fluoride was removed from water under pH from 3 to 10, which showed good applicability of AC-Al for different water quality. The adsorption process fitted well with the Langmuir model, that means monolayer adsorption, and the theoretical saturated adsorption capacity of AC-Al was 1.47 mg/g. The adsorption process conformed to the pseudo-first-order kinetic model. Fluoride removal was not affected by sulfate, chloride and bicarbonate ion (1000 mg/L), as well as humic acid, but the adsorption efficiency decreased by 21% and 11% respectively when the chloride and bicarbonate ion concentration was 3000 mg/L. The removal rate of fluoride in the coal mining water reaches 84.9% when AC-Al was 10 g/L within 30 s, and the concentration was reduced from 4.85 mg/L to 0.73 mg/L, which met the requirements of “Environmental Quality Standard for Surface Water” (GB3838-2002) (Class I, II, III). The fluoride adsorption process in coal mining water conformed to the pseudo-first-order kinetic model as well. The element mapping of AC-Al showed that Al was uniformly loaded on the surface of activated carbon; and fluoride was evenly adsorbed on AC-Al which was similar to Al distribution, indicating that Al was the active site for fluoride adsorption. According to the results of X-ray photoelectron spectroscopy, the binding energy of Al increased from 74.20 eV to 74.28 eV and 77.80 eV ( two binding states), implied that the Al-FOH, Al-F were formed on the surface of AC-Al after adsorption, which is the direct cause of rapid and stable defluoridation. Meanwhile,there was very little Al dissolution from the adsorbent (0.34 μg/g). The aluminum modified activated carbon prepared by mechanochemical method had good defluoridation capacity, which could provide a new universal technical route for the preparation of adsorbents, and a support to remove fluoride from coal mining water.

国家自然科学基金青年基金资助项目（52100070）；国家能源集团科技创新资助项目（GJNY2030XDXM-19-04.2）；煤炭开采水资源保护与利用国家重点实验室自主研发资助项目（SHGF-16-20）

齐永辉，包一翔，李　俏，等. 一步固相反应制备铝改性活性炭对矿井水中氟化物的超快去除[J]. 煤炭科学技术，2023，51（S1）：461−469.

QI Yonghui，BAO Yixiang，LI Qiao，et al. Ultrafast uptake of fluoride from coal mining water by aluminum modified activated carbon prepared through one-step solid phase reaction[J]. Coal Science and Technology，2023，51（S1）：461−469.