Wang Huan, Zhao Bing, Zhu Fenfen, Chen Qian, Zhou Tiantian, Wang Yiyu
School of Environment & Natural Resources, Renmin University of China, No. 59 Zhongguancun Street, Beijing 100872, China.
School of Environment & Natural Resources, Renmin University of China, No. 59 Zhongguancun Street, Beijing 100872, China.
Sci Total Environ. 2023 Apr 20;870:161929. doi: 10.1016/j.scitotenv.2023.161929. Epub 2023 Jan 31.
Municipal solid waste incineration (MSWI) fly ash usually needs to undergo dechlorination or heavy metal stabilization pretreatment for further treatment, recycling or disposal. In this paper, the removal effect of chlorine in fly ash by water washing, lactic acid, citric acid and microwave treatment was studied, and XANES was used to analyze chlorine chemical form in fly ash. In addition, the heavy metals in fly ash were also checked. The results indicated that double washing and triple washing could remove 88.0 % and 95.5 % of chlorine from fly ash respectively. The "double water washing + microwave/organic acid" could remove about 96.6 % of chlorine, and 42.9 % and 47.2 % of insoluble chloride respectively. The microwave treatment could maximize the stabilization of heavy metals with a BI value of 39.1 %, 0.11 %, 1.65 %, 15.4 % and 3.98 % for Cd, Cr, Cu, Pb and Zn. The elution of heavy metals by citric acid was obvious. "Double water washing + citric acid" removed 87.0 % of Cd, 17.2 % of Cr, 11.9 % of Cu, 39.6 % of Pb and 43.6 % of Zn, but the environmental risk of Cu and Cr increased about 2-3 % after the treatment. The results of this study provide guidance for the pretreatment of fly ash before resource utilization.
城市固体废物焚烧（MSWI）飞灰通常需要进行脱氯或重金属稳定化预处理，以便进一步处理、回收或处置。本文研究了水洗、乳酸、柠檬酸和微波处理对飞灰中氯的去除效果，并采用X射线吸收近边结构（XANES）分析飞灰中氯的化学形态。此外，还对飞灰中的重金属进行了检测。结果表明，两次水洗和三次水洗分别可去除飞灰中88.0%和95.5%的氯。“两次水洗+微波/有机酸”可去除约96.6%的氯，以及分别42.9%和47.2%的不溶性氯化物。微波处理可使重金属的稳定化程度最大化，镉（Cd）、铬（Cr）、铜（Cu）、铅（Pb）和锌（Zn）的生物可利用性（BI）值分别为39.1%、0.11%、1.65%、15.4%和3.98%。柠檬酸对重金属的洗脱作用明显。“两次水洗+柠檬酸”去除了87.0%的Cd、17.2%的Cr、11.9%的Cu、39.6%的Pb和43.6%的Zn，但处理后Cu和Cr的环境风险增加了约2-3%。本研究结果为飞灰资源化利用前的预处理提供了指导。
