School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
Chemosphere. 2022 Dec;308(Pt 2):136387. doi: 10.1016/j.chemosphere.2022.136387. Epub 2022 Sep 8.
Global sustainable development faces challenges in greenhouse gas emissions, consumption of energy and non-renewable resources, environmental pollution, and waste landfilling. Current technologies for immobilization of heavy metals face similar challenges; for example, the use of cement, magnesia, lime, and other binders for immobilization of heavy metals is associated with carbon dioxide emission and consumption of limestone/magnesite and energy. In these contexts, this study introduced a novel and sustainable method for immobilization of lead (Pb) by using an industrial solid waste (ladle furnace slag, LFS) and a greenhouse gas (carbon dioxide). In this laboratory investigation, LFS was first mixed with the lead nitrate and then treated by conventional curing (without carbon dioxide) and carbonation curing (with carbon dioxide) for different periods. The treated LFS were then analyzed by various chemical analyses and microanalysis. The results showed that LFS with conventional curing is not effective in immobilization of lead, while LFS with carbonation curing can effectively immobilize lead. The leaching concentrations of Pb from carbonated LFS were four orders of magnitude lower than those with conventional curing. LFS can achieve carbon dioxide uptake of up to 8% of LFS mass. During the carbonation process, carbonates were produced and wrapped LFS particles to prevent the release of lead, lead nitrate was also carbonated into lead carbonate, and the pH of LFS was reduced to 9.36-9.58, close to the minimum solubility of lead carbonate; these are the main reasons for lead immobilization. In summary, the use of LFS with carbon dioxide for immobilization of lead can not only sequester carbon dioxide, but also reduce the cost of binders, non-renewable resource consumption, energy use, and LFS landfilling.
全球可持续发展面临着温室气体排放、能源和不可再生资源消耗、环境污染和废物填埋等方面的挑战。目前用于固定重金属的技术也面临着类似的挑战；例如，使用水泥、氧化镁、石灰和其他粘合剂固定重金属会产生二氧化碳，并消耗石灰石/菱镁矿和能源。在这种情况下，本研究提出了一种利用工业固体废物（钢包炉渣，LFS）和温室气体（二氧化碳）固定铅（Pb）的新型可持续方法。在这项实验室研究中，首先将 LFS 与硝酸铅混合，然后通过常规固化（无二氧化碳）和碳酸化固化（有二氧化碳）处理不同时间。然后通过各种化学分析和微观分析对处理后的 LFS 进行分析。结果表明，常规固化的 LFS 对铅的固定效果不佳，而碳酸化固化的 LFS 可以有效固定铅。碳酸化 LFS 中 Pb 的浸出浓度比常规固化低四个数量级。LFS 可以达到 8%的 LFS 质量的二氧化碳吸收量。在碳酸化过程中，生成了碳酸盐并包裹了 LFS 颗粒，以防止铅的释放，硝酸铅也被碳酸化为碳酸铅，LFS 的 pH 值降低至 9.36-9.58，接近碳酸铅的最小溶解度；这些是铅固定的主要原因。总之，使用 LFS 和二氧化碳固定铅不仅可以封存二氧化碳，还可以降低粘合剂、不可再生资源消耗、能源使用和 LFS 填埋的成本。
