Grba Nenad, Grengg Cyrill, Petronijević Mirjana, Dietzel Martin, Baldermann Andre
Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovica 3, 21000 Novi Sad, Serbia.
Institute of Applied Geosciences and NAWI Graz Geocenter, Graz University of Technology, Rechbauerstraße 12, 8010 Graz, Austria.
Polymers (Basel). 2023 Apr 21;15(8):1971. doi: 10.3390/polym15081971.
Geopolymers are inorganic, chemically resistant aluminosilicate-based binding agents, which remove hazardous metal ions from exposed aqueous media. However, the removal efficiency of a given metal ion and the potential ion remobilization have to be assessed for individual geopolymers. Therefore, copper ions (Cu) were removed by a granulated, metakaolin-based geopolymer (GP) in water matrices. Subsequent ion exchange and leaching tests were used to determine the mineralogical and chemical properties as well as the resistance of the Cu-bearing GPs to corrosive aquatic environments. Experimental results indicate the pH of the reacted solutions to have a significant impact on the Cu uptake systematics: the removal efficiency ranged from 34-91% at pH 4.1-5.7 up to ~100% at pH 11.1-12.4. This is equivalent to Cu uptake capacities of up to 193 mg/g and 560 mg/g in acidic versus alkaline media. The uptake mechanism was governed by Cu-substitution for alkalis in exchangeable GP sites and by co-precipitation of gerhardtite (Cu(NO)(OH)) or tenorite (CuO) and spertiniite (Cu(OH)). All Cu-GPs showed excellent resistance to ion exchange (Cu release: 0-2.4%) and acid leaching (Cu release: 0.2-0.7%), suggesting that tailored GPs have a high potential to immobilize Cu ions from aquatic media.
地质聚合物是一种无机的、具有化学抗性的铝硅酸盐基粘结剂，可从暴露的水介质中去除有害金属离子。然而，对于每种地质聚合物，都必须评估其对特定金属离子的去除效率以及潜在的离子再迁移情况。因此，采用一种基于偏高岭土的粒状地质聚合物（GP）在水基质中去除铜离子（Cu）。随后通过离子交换和浸出试验来确定含铜地质聚合物的矿物学和化学性质以及其对腐蚀性水生环境的抗性。实验结果表明，反应溶液的pH值对铜的吸收系统有显著影响：在pH值为4.1 - 5.7时，去除效率在34% - 91%之间，而在pH值为11.1 - 12.4时，去除效率高达约100%。这相当于在酸性和碱性介质中，铜的吸收容量分别高达193 mg/g和560 mg/g。吸收机制是通过在可交换的地质聚合物位点上用铜取代碱，以及通过铜硝石（Cu(NO)(OH)）、黑铜矿（CuO）和水胆矾（Cu(OH)）的共沉淀来实现的。所有含铜地质聚合物对离子交换（铜释放率：0% - 2.4%）和酸浸出（铜释放率：0.2% - 0.7%）均表现出优异的抗性，这表明定制的地质聚合物具有从水生介质中固定铜离子的巨大潜力。
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