Thai local clays: Munpoo clay (MC) and Dindang clay (DC) were utilized as the adsorbents for preparation of the lake pigments from sappan wood. The lake pigment which was prepared by using MC as the adsorbent (L-MC) appeared reddish-brown while a deeper reddish-brown color of the lake pigment (L-DC) was obtained by using DC as the adsorbent. Characterization of MC, DC, L-MC, and L-DC was accomplished by XRD, SEM, FT-IR, BET, TGA and UV-Vis DRS. The effects of adsorbent dosage, pH of sappan wood extract and time on the adsorption were also investigated. The results revealed that silicon oxide and aluminium silicate hydroxide were identified as the main component of MC and DC. L-MC and L-DC exhibited similar XRD pattern compared to MC and DC but with the lower crystallinities. Brazilein from sappan wood could not only form complexes with Al and Si on the surface of the clays but also interact with clay surface via electrostatic interactions, which led to the reddish-brown color of L-MC and L-DC. Furthermore, our method could benefit and promote uses of natural clays in the production of lake pigment which could be used in paints and textile dyeing processes.

The sensor provides highly Hg2+-sensitivity and can enhance the emission in live cell.

In this study, a laccaic acid-modified TiO2 photocatalyst (Lac-TiO2) was prepared via an impregnation method with 0.50, 1.00, 2.50, and 5.00 wt.% laccaic acid. The products’ physical properties were examined through X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoemission spectroscopy (XPS), UV-Vis diffused reflectance spectroscopy (DRS), Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption/desorption, and photoluminescence (PL) spectroscopy. A possible photocatalytic mechanism was also proposed. XRD patterns revealed the anatase phase of TiO2 and Lac-TiO2 samples. High-magnification FE-SEM images showed that the TiO2 and Lac-TiO2 samples exhibited spherical-like structures. XPS results complementarily confirmed the presence of Ti, O, and C as the main elements of the Lac-TiO2 samples. Interestingly, the DRS spectra of the Lac-TiO2 samples extended into the visible region. FTIR spectra presented the characteristic bands of TiO2 and hydroxyl groups on the TiO2 surface. Instead of hydroxyl groups, the characteristic bands of laccaic acid were observed on the surface of the Lac-TiO2 samples. The photocatalytic properties of the Lac-TiO2 samples were evaluated in terms of methyl orange degradation under visible light irradiation. The Lac-TiO2 samples showed higher photocatalytic performance than the TiO2 sample.

Correction for ‘Triple detection modes for Hg2+ sensing based on a NBD-fluorescent and colorimetric sensor and its potential in cell imaging’ by Sasiwimon Kraithong et al., New J. Chem., 2018, DOI: 10.1039/c8nj01915k.