Cadmium (Cd) is a harmful element to human health and biodiversity. The removal of Cd from groundwater is of great significance to maintain the environmental sustainability and biodiversity. In this work, a novel low-temperature roasting associated with alkali was applied to synthesize an eco-friendly adsorbent using coal fly ash. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray fluorescence, and X-ray photoelectron spectroscopy were applied to analyze the physical and chemical characteristics of the adsorbent. The experiments show that a significant improvement in specific surface area and activity of adsorbent was observed in this study. The functional groups of Na–O and Fe–O were verified to be beneficial in the removal of Cd²⁺. The material capacity to adsorb Cd²⁺ was considerably improved, and the maximum uptake capacity was 61.8 mg g⁻¹ for Cd²⁺ at 25 °C. Furthermore, pH and ionic strength play critical roles in the adsorption process. The Langmuir and pseudo-second-order models can appropriately describe the adsorption behavior, and the enhanced adsorption ability of Cd²⁺ by modified coal fly ash was attributed to ion-exchange, co-precipitation, and complexation. Higher sorption efficiency was maintained after two regeneration cycles. These results offer valuable insights to develop high-performance adsorbent for Cd²⁺ removal.

镉是对人类健康和生物多样性的有害元素。从地下水中去除镉对维持环境的可持续性和生物多样性具有重要意义。在这项工作中，一种新型的与碱相关的低温焙烧被应用来利用粉煤灰合成一种环保型吸附剂。应用扫描电子显微镜，傅立叶变换红外光谱，X射线荧光和X射线光电子能谱分析吸附剂的物理和化学特性。实验表明，在该研究中观察到比表面积和吸附剂活性的显着改善。证实Na–O和Fe–O的官能团对去除Cd ²⁺有益。吸附Cd ²⁺的材料容量在25°C下，Cd ²⁺的最大吸收量为61.8 mg g ^-1。此外，pH和离子强度在吸附过程中起关键作用。Langmuir模型和拟二阶模型可以恰当地描述吸附行为，而改性粉煤灰对Cd ²⁺的吸附能力增强归因于离子交换，共沉淀和络合。在两个再生循环后保持较高的吸附效率。这些结果为开发用于去除Cd ²⁺的高性能吸附剂提供了宝贵的见识。