Enriched in phosphorus, sewage sludge ash has been extensively studied and applied as a secondary source for phosphorus recovery. Wet extraction, especially acid washing, is one of the most feasible methods to recover phosphorus from the ash due to its ease of operation, high efficiency and low cost. However, the management of the resultant acid residue was seldom addressed. In this study, special focus was paid to the reuse and recycling of the acid residue by an alkaline activation method. Its adsorption performance towards four different heavy metals in aqueous solutions was evaluated by batch and fixed-bed column adsorption experiments. The obtained material showed a high BET specific area (98.29 m²/g) and a total pore volume (0.114 cm³/g), and effectively removed Cd(II), Cu(II), Pb(II) and Zn(II) from aqueous solutions with the maximum adsorption capacity of around 26.8, 22.2, 53.3 and 13.5 mg/g respectively. It could be loaded in a fixed-bed column to continuously remove heavy metals especially for Pb(II). The proposed method to recycle the acid residue makes the wet extraction methods designing to recover phosphorus from incinerated sewage sludge complete without the generation of waste, which contributes to circular economy and a sustainable future.

污水污泥灰分中富含磷，已被广泛研究并用作磷回收的辅助来源。湿法提取，特别是酸洗，由于操作简便，效率高，成本低，是从灰分中回收磷的最可行方法之一。然而，很少解决所得酸残基的管理。在这项研究中，特别关注通过碱性活化方法对酸残渣的再利用和再循环。通过分批和固定床柱吸附实验评估了其对水溶液中四种不同重金属的吸附性能。所得材料显示出高的BET比表面积（98.29m ² / g）和总孔体积（0.114cm ^3）/ g），并从水溶液中有效去除Cd（II），Cu（II），Pb（II）和Zn（II），最大吸附容量分别约为26.8、22.2、53.3和13.5 mg / g。可以将其装入固定床色谱柱中以连续除去重金属，尤其是对于Pb（II）。所提出的回收酸残留物的方法使设计用于从焚化的污水污泥中回收磷而又不产生废物的湿法提取方法得以完成，这有助于循环经济和可持续的未来。