Qin Jiafu, Zhang Chuchu, Chen Zhenguo, Wang Xiaojun, Zhang Yangzhong, Guo Lu
School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China.
School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China; School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510641, China.
Chemosphere. 2022 Jul;298:134302. doi: 10.1016/j.chemosphere.2022.134302. Epub 2022 Mar 15.
Pyrolysis combined with land application for dewatered municipal sludge disposal revealed advantages in heavy metals solidification and resource utilization compared with other disposal technologies. In this study, utilizing dewatered municipal sludge for calcium-containing porous adsorbent preparation via pyrolysis was proposed and verified. After pyrolyzing at 900 ° C (Ca-900), the dewatered sludge obtained maximum adsorption capacity (83.95 mg P⋅ g) and the adsorption process conformed to the pseudo-second-order model and double layer model. Characteristic analysis showed the predominant adsorption mechanism was precipitation. Continuous column bed experiment indicated 2 g adsorbent could remove 4.27 mg phosphorus from tail wastewater with the initial phosphorus concentration of 1.03 mg ⋅ L. No heavy metals leaching was observed from Ca-900 adsorbent with pH value exceeding 1.0, and merely 1% addition of Ca-900 adsorbent (after actual water phosphorus adsorption) with soil could extremely promote the early growth of seedlings. Economic estimates demonstrated that this cost-effective modification could generate the most add-on value production. Based on these results, the strategy of 'one treatment but two uses' was proposed in this study, converting the wastes to resource and providing a native strategy for sludge disposal and resource recovery.
与其他处置技术相比，热解结合土地施用处置脱水城市污泥在重金属固化和资源利用方面具有优势。本研究提出并验证了利用脱水城市污泥通过热解制备含钙多孔吸附剂的方法。在900℃热解后（Ca-900），脱水污泥获得最大吸附容量（83.95 mg P·g），吸附过程符合准二级模型和双层模型。特征分析表明，主要吸附机制为沉淀。连续柱床实验表明，2 g吸附剂可从初始磷浓度为1.03 mg·L的尾水中去除4.27 mg磷。pH值超过1.0时，未观察到Ca-900吸附剂有重金属浸出，在土壤中仅添加1%的Ca-900吸附剂（实际吸附水中磷后）就能极大地促进幼苗的早期生长。经济评估表明，这种具有成本效益的改性方法能够产生最大的附加值产品。基于这些结果，本研究提出了“一处理双利用”策略，将废物转化为资源，为污泥处置和资源回收提供了一种本土策略。
