College of Water Sciences, Beijing Normal University, Beijing 100875, China..
College of Water Sciences, Beijing Normal University, Beijing 100875, China.
J Environ Sci (China). 2019 May;79:91-99. doi: 10.1016/j.jes.2018.11.007. Epub 2018 Nov 16.
Because of its high adsorption capacity, biochar has been used to stabilize metals when remediating contaminated soils; to date, however, it has seldom been used to remediate contaminated sediment. A biochar was used as a stabilization agent to remediate Cu- and Pb-contaminated sediments, collected from three locations in or close to Beijing. The sediments were mixed with a palm sawdust gasified biochar at a range of weight ratios (2.5%, 5%, and 10%) and incubated for 10, 30, or 60 days. The performance of the different treatments and the heavy metal fractions in the sediments were assessed using four extraction methods, including diffusive gradients in thin films, the porewater concentration, a sequential extraction, and the toxicity characteristic leaching procedure. The results showed that biochar could enhance the stability of heavy metals in contaminated sediments. The degree of stability increased as both the dose of biochar and the incubation time increased. The sediment pH and the morphology of the metal crystals adsorbed onto the biochar changed as the contact time increased. Our results showed that adsorption, metal crystallization, and the pH were the main controls on the stabilization of metals in contaminated sediment by biochar.
由于具有高吸附能力，生物炭已被用于稳定修复污染土壤中的金属；然而，迄今为止，它很少被用于修复污染沉积物。本研究采用生物炭作为稳定剂来修复采自北京及其附近三个地点的 Cu 和 Pb 污染沉积物。将沉积物与棕榈木屑气化生物炭以 2.5%、5%和 10%（重量比）混合，并在 10、30 或 60 天内进行孵化。采用四种提取方法（薄膜扩散梯度法、孔隙水浓度法、连续提取法和毒性特征浸出程序）评估不同处理方法和沉积物中重金属形态的性能。结果表明，生物炭可以增强污染沉积物中重金属的稳定性。随着生物炭剂量和孵化时间的增加，稳定性的增强程度也随之增加。随着接触时间的增加，沉积物 pH 值和吸附在生物炭上的金属晶体的形态发生了变化。研究结果表明，吸附、金属结晶和 pH 值是生物炭稳定污染沉积物中金属的主要控制因素。
