以城市污泥为原料，通过尿素活化和两段式热解制备生物质活性炭。结果表明，污泥与尿素的固液比、第1段和第2段的热解温度对污泥活性炭比表面积有较大影响。当活化液中尿素质量分数为20%时，干污泥与尿素的质量比为1∶2，活化时间为24 h，在氮气保护控制第1段热解温度为550℃、停留时间2 h，第2段热解温度为650℃、停留时间1 h，经自然冷却并酸洗干燥后的活性炭样品的比表面积可达到325 m²/g，高于未活化时相同工艺条件下所得到的炭样品（56 m²/g）。通过对第1段和第2段热解产物的X-射线衍射和热重分析发现，尿素在活化阶段能迅速到达污泥表面并在1段热解时参与污泥碳化而形成类石墨结构的C₃N₄，在第2段升温时氮化碳分解为氨气和二氧化碳并从石墨晶区中释放，从而在污泥碳基表面形成孔穴。

In this study, urea is used as a novel activator for sludge and preparation of activated carbon.The results indicate that activated carbon made from urea activated sludge can have a BET surface area of 325 m²·g^-1 when the raw sludge is activated by urea and then is carbonized by sequenced two-stage pyrolysis.The optimal operation parameters include that the ratio of solid to urine is 1:2 and the pyrolysis temperatures in the 1^st and 2^nd periods are 550℃ and 650℃, respectively.Further analysis by X-ray diffraction and thermogravimetry shows that urea is changed into graphitic C₄N₃ in the first pyrolytic stage and then decomposed to leave pores in the second stage.