Influence of indigo-hydroxyl interactions on the properties of sepiolite-based Maya blue pigment

Sustainable application study of disposable medical waste masks in cement based on green Fenton reaction

“…These four new peaks are attributed to the vibration of FeO bonds in FeOOH 44 . Additionally, two absorption peaks at 3426 and 613 cm −1 originate from OH groups within FeOOH 45,46 . The observation from Figure 3 reveals that both DMM fibers and M‐DMM fibers exhibit a C1s peak at a binding energy (BE) of 284.80 eV.…”

“…44 Additionally, two absorption peaks at 3426 and 613 cm À1 originate from OH groups within FeOOH. 45,46 The observation from Figure 3 reveals that both DMM fibers and M-DMM fibers exhibit a C1s peak at a binding energy (BE) of 284.80 eV. However, compared to the XPS spectrum of DMM fiber, the XPS spectrum of M-DMM fiber shows…”

Structure and morphology of red pigments based on sepiolite

“…After heating Sep to 200 °C, the FTIR spectra were similar to those of Sep at room temperature, except the bands of zeolitic water (3403, 3252, and 1660 cm −1 ) that became weaker, indicating that most of the zeolitic water was lost. 31 After the heating treatment, the characteristic band at 3683 cm −1 ascribed to the stretching vibration of the O-H groups, Mg 3 OH, still remained until 750 °C and then shifted to smaller wavelengths (3674 cm −1 ). At 800 °C the band's intensity had diminished considerably, as the dehydroxylation of MgOH was achieved according to the TG results.…”

“…They have been used as potential and favourable siliceous precursors to fabricate organic/inorganic and inorganic/inorganic pigments with different methods of synthesis. [28][29][30][31][32] with an orthorhombic crystalline structure, and consists of nanometer-sized fibers. Structurally, it is formed by blocks and channels extending in the fiber direction.…”

“…28 In addition, Sep has been used for the preparation of pigments by the incorporation of chromophore molecules in the clay structure. Maya blue pigments have been synthesized with indigo molecules incorporated into Sep by heating, with indigo being hosted within the tunnels of the Sep. 29,31,39 Szadkowski et al 32 prepared hybrid pigments from organic chromophores (alizarin and purpurin) and Sep as a mineral support to be used as organic-inorganic pH indicators. Concerning pigments with red colour, Tian et al 20 synthesized red hybrid pigments clay/Fe 2 O 3 using Sep and halloysite as carriers.…”