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利用脱水污泥为原料在不同温度下热解制备污泥生物炭(sewage sludge biochar,SSBC),研究SSBC的磷吸附特征。700℃下制备的SSBC(B700)具有最好的磷吸附性能(5.93 mg·g~(-1),以P计),且效果优于其他类型的生物炭和活性炭,可以用作一种廉价的磷吸附剂。磷以稳定的形态吸附于SSBC上,SSBC吸附磷的机制主要是其表面的Ca O和Mg O与磷酸根结合形成稳定的磷酸盐沉淀。吸附条件优化表明,吸附温度升高促进SSBC对磷的吸附,SSBC吸附磷的适宜pH为6~8,共存离子CO2-3对磷吸附具有明显的抑制。采用Langmuir方程、Freundlich方程及Langmuir-Freundlich方程均能较好地拟合B700对磷的吸附,表明磷在SSBC表面的吸附可能受多种机制影响。
Sewage sludge biochar (SSBC) was prepared by pyrolysis of dewatered sludge at different temperatures to study the phosphorus adsorption characteristics of SSBC. SSBC (B700) prepared at 700 ℃ has the best phosphorus adsorption capacity (5.93 mg · g -1), which is better than other types of biochar and activated carbon and can be used as a cheap Of phosphorus adsorbent. Phosphorus is adsorbed on SSBC in a stable form. The mechanism of phosphorus adsorption by SSBC is mainly that CaO and MgO on the surface combine with phosphate to form stable phosphate precipitate. The adsorption conditions showed that the adsorption temperature increased the adsorption of phosphorus by SSBC. The suitable pH of phosphorus adsorption by SSBC was 6 ~ 8, and the coexistence of ion CO2-3 significantly inhibited the adsorption of phosphorus. The adsorption of phosphorus by B700 can be well fitted by the Langmuir equation, the Freundlich equation and the Langmuir-Freundlich equation, indicating that the adsorption of phosphorus on the SSBC surface may be affected by various mechanisms.