载镧酒糟污泥生物炭对磷的吸附性能及机理

为实现市政污泥的无害化和资源化利用，以酒糟和市政污泥为原料热解制备酒糟污泥生物炭(LBC_Z)，采用共沉淀法将镧(La)负载到LBC_Z表面制得La改性酒糟污泥生物炭(La-LBC_Z)，探究了改性剂浓度、La-LBC_Z投加量、溶液初始pH和共存离子对La-LBC_Z吸附磷的影响，使用SEM-EDS、BET、XRD、FTIR和XPS等表征手段分析了吸附机理。结果表明：改性剂浓度为0.1 mol·L⁻¹时La-LBC_Z对磷的吸附效果最好(吸附量为68.32 mg·g⁻¹)，为改性前的6倍；吸附过程符合准二级动力学模型和Langmuir模型，为单分子层表面的化学吸附。此外，生物炭孔隙结构不发达，La以氢氧化物形态负载到生物炭表面，络合反应是其主要的吸附机理。在吸附-脱附实验中，La-LBC_Z经过5次循环后吸附量为61.2 mg·g⁻¹，吸附率为87.79%，脱附量为52.65 mg·g⁻¹，脱附率为75.52%，说明其具有良好的循环性能和磷回收性能。

Fabrication of La-LBCZ composites for phosphate removal: Adsorption performance and mechanism

In order to realize the harmless and resource utilization of municipal sludge, distiller's grains-sludge based biochar (LBCZ) was prepared by pyrolysis of distiller's grains and municipal sludge. La-modified distiller's grains-sludge based biochar (La-LBCZ) was prepared by coprecipitating lanthanum (La) onto the surface of LBCZ. The effects of modifier concentration, La-LBCZ dosage, initial solution pH, and coexisting ions on phosphorus adsorption by La-LBCZ were investigated. The corresponding adsorption mechanism was exposed by SEM-EDS, BET, XRD, FTIR, and XPS. The results showed that the adsorption effect of La-LBCZ to phosphorus significantly increased (68.32 mg·g−1) at 0.1 mol·L−1 modifier concentration, which was six times that of unmodified biochar. The adsorption behavior of La-LBCZ was consistent with the pseudo-second-order model and the Langmuir model, which indicated that above adsorption was the chemisorption on the monolayer. In addition, the pore structure of biochar was undeveloped, La was loaded on the biochar surface as hydroxides, and complexation reaction was the primary adsorption mechanism. After five adsorption-desorption cycles, La-LBCZ exhibited a good recycling and phosphorus recovery performance, the remained adsorption capacity was 61.2 mg·g−1, the adsorption rate was 87.79%, the desorption capacity was 52.65 mg·g−1, and the desorption rate was 75.52%.