Work

Optimizing Cu2+ adsorption with low-temperature sintered dolomite-based geopolymer

Year: 2025

Type: article

Abstract: Sintering process significantly improves Removal Efficiency (RE) of Copper (Cu) ions by enhancing microstructural properties, creating new active sites and increasing ceramic material densification. However, geopolymer typically requires high-sintering temperature above 1200˚С, leading to substantial energy consumption and increased production costs. In contrast, dolomite-based geopolymer reduces the sintering temperature to 900 ˚С by producing metal oxides like periclase (MgO) and lime (CaO), which act as self-fluxing agent during the sintering process. Therefore, this study aims to develop a sustainable ceramic geopolymer adsorbent using dolomite as the primary precursor, utilizing low sintering temperature of 900˚C. The effects of low sintering temperature on the microstructure, pore sizes, chemical changes and RE of Cu ions were investigated. Characterization techniques were used including Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX), X-ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and Synchrotron Radiation X-ray Fluorescence (SR-XRF) were used. Heating dolomite-based geopolymer at 900˚С achieved the highest RE of 81.1%, followed by unsintered dolomite-based geopolymer (46.9%) and raw dolomite (14.5%). The results showed that sintering at 900°C with a heating rate of 5°C/min produced a smoother surface with a more spherical dolomite shape. Additionally, the formation of MgO and CaO further enhanced the removal of Cu2+ ions. SR-XRF analysis detected 80.34% of Cu on sintered dolomite-based geopolymer after adsorption, suggesting that Cu2+ has successfully replaced Ca2+. Thus, the sintering process influences final microstructure formation, improving RE of Cu ions. This indicates that sintered dolomite-based geopolymer using low sintering temperature (900˚C) can effectively remove Cu ions in wastewater treatment.

Source: Case Studies in Construction Materials

DOI: 10.1016/j.cscm.2025.e04794