Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia.
Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia.
J Hazard Mater. 2018 May 15;350:98-107. doi: 10.1016/j.jhazmat.2018.02.023. Epub 2018 Feb 12.
Preventing or reducing negative effects on the environment from the waste landfilling is the main goal defined by the European Landfill Directive. Generally geopolymers can be considered as sustainable binders for immobilization of hazardous wastes containing different toxic elements. In this paper the influence of addition of high amount of lead on structure, strength, and leaching behavior (the effectiveness of Pb immobilization) of fly ash-based geopolymers depending on the geopolymer curing conditions was investigated. Lead was added during the synthesis of geopolymers in the form of highly soluble salt - lead-nitrate. Structural changes of geopolymers as a result of lead addition/immobilization were assessed by means of XRD, SEM/EDS, and Si MAS NMR analysis. Investigated curing conditions significantly influenced structure, strength and leaching behavior of geopolymers. High addition of lead caused a sizeable decrease in compressive strength of geopolymers and promoted formation of aluminum-deficient aluminosilicate gel (depolymerization of aluminosilicate gel), regardless of the curing conditions investigated. According to the EUWAC limitations, 4% of lead was successfully immobilized by fly ash-based geopolymers cured for 28 days in a humid chamber at room temperature.
防止或减少垃圾填埋对环境的负面影响是欧洲垃圾填埋指令规定的主要目标。一般来说，地质聚合物可以被认为是一种可持续的粘合剂，用于固定含有不同有毒元素的危险废物。本文研究了在不同的地质聚合物固化条件下，高含量铅的添加对基于粉煤灰的地质聚合物的结构、强度和浸出行为（Pb 固定效果）的影响。铅是通过添加高可溶性盐-硝酸铅的形式加入到地质聚合物的合成过程中。通过 XRD、SEM/EDS 和 Si MAS NMR 分析评估了铅添加/固定后地质聚合物的结构变化。研究的固化条件显著影响了地质聚合物的结构、强度和浸出行为。高铅的添加导致地质聚合物的抗压强度显著下降，并促进了铝缺铝硅酸盐凝胶的形成（铝硅酸盐凝胶的解聚），无论所研究的固化条件如何。根据 EUWAC 的限制，在室温下的潮湿室中固化 28 天的粉煤灰基地质聚合物成功地固定了 4%的铅。
