Advanced Materials Institute, Shandong Engineering Research Centre of Municipal Sludge Disposal, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250014, China.
Shandong Shanke Institute of Ecological Environment Co., Ltd., Jinan 250000, China.
Int J Environ Res Public Health. 2022 Nov 30;19(23):16041. doi: 10.3390/ijerph192316041.
The practical application of nanoscale zero-valent iron (NZVI) is restricted by its easy oxidation and aggregation. Here, sludge biochar (SB) was used as a carrier to stabilize NZVI for Cd and Cu removal. SB supported NZVI (SB-NZVI) was synthesized using the carbothermic method. The superior preparation conditions, structural characteristics, and performance and mechanisms of the SB-NZVI composites for the removal of Cd and Cu were investigated via batch experiments and characterization analysis. The optimal removal capacities of 55.94 mg/g for Cd and 97.68 mg/g for Cu were achieved at a Fe/sludge mass ratio of 1:4 and pyrolysis temperature of 900 °C. Batch experiments showed that the SB-NZVI (1:4-900) composite had an excellent elimination capacity over a broad pH range, and that weakly acidic to neutral solutions were optimal for removal. The XPS results indicated that the Cd removal was mainly dependent on the adsorption and precipitation/coprecipitation, while reduction and adsorption were the mechanisms that play a decisive role in Cu removal. The presence of Cd had an opposite effect on the Cu removal. Moreover, the SB-NZVI composites made of municipal sludge greatly reduces the leaching toxicity and bio-availability of heavy metals in the municipal sludge, which can be identified as an environmentally-friendly material.
纳米零价铁（NZVI）的实际应用受到其易氧化和聚集的限制。在这里，污泥生物炭（SB）被用作载体来稳定 NZVI 以去除 Cd 和 Cu。使用碳热法合成了 SB 负载的 NZVI（SB-NZVI）。通过批量实验和表征分析，研究了 SB-NZVI 复合材料去除 Cd 和 Cu 的优越制备条件、结构特征、性能和机制。在 Fe/污泥质量比为 1:4 和热解温度为 900°C 的最佳条件下，SB-NZVI 对 Cd 和 Cu 的去除容量分别达到 55.94mg/g 和 97.68mg/g。批量实验表明，SB-NZVI（1:4-900）复合材料在较宽的 pH 范围内具有优异的消除能力，且弱酸性至中性溶液最有利于去除。XPS 结果表明，Cd 的去除主要依赖于吸附和沉淀/共沉淀，而还原和吸附是决定 Cu 去除的机制。Cd 的存在对 Cu 的去除有相反的影响。此外，由城市污泥制成的 SB-NZVI 复合材料大大降低了城市污泥中重金属的浸出毒性和生物有效性，可被视为一种环保材料。
