Biomimetic calcium carbonate with hierarchical porosity produced using cork as a sustainable template agent. Issue 1 (February 2020)

• Record Type: Journal Article
• Authors: Scalera, Francesca; Carbone, Luigi; Bettini, Simona; Pullar, Robert C.; Piccirillo, Clara
• Is Part Of: Journal of environmental chemical engineering. Volume 8:Issue 1(2020)
• Publication Date: 2020-02
• Subjects: Calcium carbonate -- Cork -- Porosity -- Biomimetic -- Environment remediation; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2019.103594
• Languages: English
• ISSNs: 2213-2929

Abstract

Graphical abstract: Highlights: Calcium carbonate (CaCO3 ) was prepared using cork as template agent. Pyrolysed cork powder was infiltrated with calcium precursor and thermally treated. CaCO3 shows hierarchical porosity – at micro and nanoscale level. Material showed highest surface area ever reported for plant-based template CaCO3 . Cork-derived CaCO3 suitable for environmental remediation (pollutants adsorption). Abstract: Calcium carbonate has many applications in different fields; its use in environment remediation is particularly considered, due to its non-toxicity and potentially high efficiency. The structure, morphology and surface features of calcium carbonate can greatly affect its performance. Hierarchical porosity, in particular, can be beneficial for several functional properties. In this study, we report the synthesis of biomorphic calcium carbonate using a sustainable template agent – waste cork powder. Pyrolysed cork powder was infiltrated by an appropriate calcium-containing salt and successively thermally treated. Selected precursors, different impregnation-solution concentrations and thermal conditions were tested. The resulting materials were characterised by XRD, Raman spectroscopy and SEM. Surface area and porosity features were studied by BET analysis, with a detailed study on the effect of synthesis on the mesoporosity of the materials, average sizes varying between 4−15 nm. The most valuable results were achieved with calcium acetate followed by pyrolysis performed for relatively short time period. This maintained the porous 3D honeycomb cork structure made of ∼20 μm hexagonal cells, while consisting of highly mesoporous single-phase CaCO3 . Such samples showed the highest surface area ever reported for CaCO3 prepared using a plant-based template; moreover, it also exhibited a dual-scale hierarchical porosity as, in addition to micrometer scale cellular macroporosity, it contained a significant mesoporosity in the cell walls, with a very narrow range of 3.6–3.9 nm. These promising characteristics enable the potential employment of cork-derived CaCO3 for environment remediation.