Civil Engineering and Environment Laboratory (LGCE), Mohammadia Engineering School, Mohammed V University, Rabat, Morocco.
Engineering and Materials Laboratory (LIMAT), Faculty of Science Ben M'Sik, Hassan II University, Casablanca, Morocco.
Environ Sci Pollut Res Int. 2022 Dec;29(58):87668-87679. doi: 10.1007/s11356-022-21873-9. Epub 2022 Jul 11.
Drinking water treatment sludge (DWTS) generated from water treatment plants is a global issue because of the environmental risks it imposes. Managing the abundance of DWTS in landfills remains an important issue. The reuse of these sludges as a construction material could contribute to the development of a geopolymer and mitigate the harmful effects of the excessive production of these sludges on the environment. This study aims to evaluate the effect of DWTS on the properties of Class F fly ash (FFA) geopolymers. Seven geopolymer blends were made with the addition of DWTS in the total fly ash weight of 0%, 5%, 10%, 15%, 20%, 30%, and 40%, and with an alkaline solution composed of 12 M sodium hydroxide (NaOH) and sodium silicate (NaSiO) solution; the liquid/solid and (NaSiO)/NaOH weight ratios were set to 0.75 and 2.5 respectively. The polymerization temperature was set at 60 °C and different polymerization times such as 3, 7, 14, and 28 days were considered. The bulk density, apparent porosity, compressive strength, and microstructure of the geopolymer samples were tested. The experimental results revealed that the optimum percentage of DWTS incorporation is 20 wt%, which generates a dense and homogeneous microstructure. The addition of more than 20% DWTS decreased the compressive strength from 40.87 to 35.3 MPa and bulk density from 2.134 to 2.087 g/cm due to the retention of air bubbles and evaporation of water during the polymerization process forming voids in the matrix, which results in increased apparent porosity from 19 to 22%. This investigation confirmed the feasibility of incorporating DWTS into FFA-based geopolymers.
饮用水处理厂产生的处理污泥 (DWTS) 是一个全球性的问题，因为它会带来环境风险。在垃圾填埋场中处理大量 DWTS 仍然是一个重要的问题。将这些污泥作为建筑材料再利用可以促进地质聚合物的发展，并减轻这些污泥过度生产对环境的有害影响。本研究旨在评估 DWTS 对 F 级粉煤灰 (FFA) 地质聚合物性能的影响。通过在总粉煤灰重量中添加 0%、5%、10%、15%、20%、30%和 40%的 DWTS，制作了七种地质聚合物混合物，并使用由 12 M 氢氧化钠 (NaOH) 和硅酸钠 (NaSiO) 溶液组成的碱性溶液；液体/固体和 (NaSiO)/NaOH 重量比分别设置为 0.75 和 2.5。聚合温度设定为 60°C，并考虑了不同的聚合时间，如 3、7、14 和 28 天。测试了地质聚合物样品的堆积密度、显气孔率、抗压强度和微观结构。实验结果表明，DWTS 最佳掺入量为 20wt%，可产生致密均匀的微观结构。掺入超过 20%的 DWTS 会降低抗压强度从 40.87 至 35.3 MPa 和堆积密度从 2.134 至 2.087 g/cm，这是由于聚合过程中保留气泡和蒸发水分导致形成基质中的空隙，从而使显气孔率从 19 增加到 22%。这项研究证实了将 DWTS 掺入 FFA 基地质聚合物中的可行性。
