Department of Soil Science, Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), Piracicaba, Brazil.
Department of Soil Science, Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), Piracicaba, Brazil.
Sci Total Environ. 2022 Feb 10;807(Pt 3):151001. doi: 10.1016/j.scitotenv.2021.151001. Epub 2021 Oct 15.
Arsenic (As) and lead (Pb) are potentially toxic elements capable of developing several diseases in human beings such as cancer. Several adsorbent materials, including biochars, have been adopted as alternative measures designed to reduce the availability of As and Pb in water. The retention capacity of potentially toxic elements in biochars varies according to time, feedstock, and the pyrolysis temperature to produce the biochar. Our objectives in this study were to evaluate i) the aging effect of sugarcane straw pyrolyzed biochars at 350 (BC350), 550 (BC550), and 750 °C (BC750) and their ability to immobilize As and Pb; and ii) how the pyrolysis temperature and biochar aging alter the carbon content and quality of the solution and sediment. Biochars were applied at 5% (w/w), and their aging together with As and Pb immobilization effects were evaluated every 45 days over a total period of 180 days. The results were obtained using visible ultraviolet spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy combined with physical fractionation of organic matter and multivariate statistics. The groups formed in the Principal Component Analysis indicated that the change in the availability of As and Pb was related to the aging of the biochar and the temporal changes in the content and quality of organic carbon in the sediment and solution. The pyrolysis temperature was a key factor in the (im)mobilization capacity of As and Pb during the aging of the biochar. The increase in polysaccharides and organic matter associated with the particulate fraction can enhance the release of As in solution (24%). Increasing the fraction of organic matter associated with minerals reduced the availability of Pb by 58%. These findings may provide new insights into understanding the dynamics of organic matter and its role in the immobilization of As and Pb during biochar aging.
砷（As）和铅（Pb）是潜在的有毒元素，能够在人类中引发多种疾病，如癌症。已经采用了包括生物炭在内的几种吸附材料作为替代措施，旨在降低水中 As 和 Pb 的有效性。生物炭对潜在有毒元素的保留能力因时间、原料和生产生物炭的热解温度而异。我们在这项研究中的目标是：i）评估 350°C（BC350）、550°C（BC550）和 750°C（BC750）热解的甘蔗秸秆生物炭的老化效应及其固定 As 和 Pb 的能力；ii）热解温度和生物炭老化如何改变溶液和沉积物中的碳含量和质量。生物炭以 5%（w/w）的比例施加，评估了它们在 180 天内每隔 45 天的老化及其对 As 和 Pb 固定效果的影响。结果采用可见紫外光谱和漫反射红外傅里叶变换光谱结合有机物的物理分级和多元统计分析得到。主成分分析中形成的组表明，As 和 Pb 的有效性变化与生物炭的老化以及沉积物和溶液中有机碳含量和质量的时间变化有关。热解温度是生物炭老化过程中（im）固定 As 和 Pb 能力的关键因素。与颗粒相相关的多糖和有机物含量的增加可以增强 As 在溶液中的释放（24%）。与矿物质相关的有机物质分数的增加降低了 58%的 Pb 有效性。这些发现可能为理解有机物的动力学及其在生物炭老化过程中对 As 和 Pb 的固定作用提供新的见解。
