Properties and heavy metal leaching characteristics of leachate sludge-derived biochar
Properties and heavy metal leaching characteristics of leachate sludge-derived biochar
复制标题
渗滤液污泥生物炭的性质及重金属浸出特性
DOI：
10.1002/wer.1658
复制
发表时间：
2021
影响因子：
3.1
通讯作者：
Kewu Pi
中科院分区：
文献类型：
--
作者：
Huiqin Zhang;Zixian Wang;Chenyu Du;Wenlong Liu;Andrea R. Gerson;Kewu Pi
污泥和沉积物中的重金属和类金属是令人关注的环境污染物，对人类和生态健康产生长期负面影响。在这项研究中，城市垃圾渗滤液生物处理产生的污泥在300℃至900℃下热解成渗滤液污泥衍生生物炭（LSDB），其中包含由非均相化学反应形成的复杂有机和无机（特别是重金属）物质。基于不同的先进材料分析，即热重分析（TGA）、傅里叶变换红外（FTIR）、扫描电子显微镜（SEM）和X射线衍射（XRD）分析，本研究表明LSDB的质量损失和微观结构变化主要是由于挥发物、芳环、碳酸盐和氢氧化物的分解而发生的。使用合成沉淀浸出程序 (SPLP) 评估 LSDB 中重金属的浸出行为。随着热解温度的升高，SPLP 中的最终 pH 值从 7.5 增加到 12.5。由于在碱性 pH 值下形成低溶解度沉淀物，pH 值的增加有利于 LSDB 中重金属的保留。由于沉淀和阳离子交换而不是表面络合，LSDB 中的重金属和类金属以表面沉淀物的形式存在。铬、镉、镍、铅、砷等金属和类金属浸出量均低于国家第一优先污染物最高排放标准。
Heavy metals and metalloids, in sludge and sediments, are environmental pollutants of concern with long-term negative effects on human and ecological health. In this study, sludge from biological treatment of municipal waste leachate was pyrolyzed into leachate sludge-derived biochar (LSDB) at 300℃ to 900 ℃, comprising complex organic and inorganic (particularly heavy metals) species formed from heterogeneous chemical reactions. Based on different advanced material analyses, that is, Thermogravimetric Analysis (TGA), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis, this study revealed that mass loss and microstructural changes of LSDBs occurred primarily due to decomposition of volatiles, aromatic rings, carbonates, and hydroxides. The leaching behaviors of heavy metals from LSDBs were evaluated using the Synthetic Precipitation Leaching Procedure (SPLP). The final pH in SPLP increased from 7.5 to 12.5 with pyrolysis temperature. The pH increase favored the retention of heavy metals in the LSDBs due to the formation of low soluble precipitates at alkaline pH. The heavy metals and metalloids in the LSDBs were present as surface precipitates due to precipitation and cation exchange rather than surface complexation. The leaching contents of metals and metalloids, such as Cr, Cd, Ni, Pb, and As, were all below their respective maximum discharge standards for the first priority pollutants in China.