Halloysite-polypyrrole-silver nanocomposite has been prepared via in situ photopolymerizations of pyrrole in the presence of silanized halloysite and silver nitrate as a photoinitiator. The halloysite nanoclay (HNT) was modified using the hydrogen donor silane coupling agent (DMA) in order to provide anchoring sites for the polypyrrole/silver composite (PPy@Ag). The mass loadings for both PPy and Ag have been estimated to be 21 and 26 wt%, respectively. The anchored Ag particles were found in the metallic state. The resulting PPy@Ag-modified silanized HNT has been evaluated for the potential application for impedance humidity sensors. HNT-DMA-PPy@Ag nanocomposite with different weight % of PPy@Ag (0.25 wt%, 0.5 wt%, and 1 wt%) was deposited on the pre-patterned interdigital Indium Tin Oxide (ITO) electrodes by spin coating technique. The addition of Ag nanoparticles within the nanocomposite enhances the hydrophilicity of the sensing film, which improves the sensitivity of the humidity sensors. The HNT-DMA-PPy@Ag (0.5 wt%) nanocomposite-based impedance sensors showed good sensitivity and lowered hysteresis as compared to the other ratios of the composite. The maximum calculated hysteresis loss of the HNT-DMA-PPy@Ag (0.5 wt%)-based humidity sensor is around 4.5% at 80% RH (relative humidity), and the minimum hysteresis loss estimated to be 0.05% at 20% RH levels. The response and recovery time of HNT-DMA-PPy@Ag (0.5 wt%) nanocomposite-based impedance sensors were found to be 30 and 35 s, respectively. The interesting humidity-dependent impedance properties of this novel composite make it promising in humidity sensing.

<p>This work describes the preparation of novel fluorescent bentonite clay (BP), modified with carbon quantum dots nanomaterials (CDs), and its usage as lead removal platform, the CDs was prepared using graphitic waste serving as carbon source material via hydrothermal method, and the as obtained CDs were found to be fluorescent, in spherical shape, positively charged and smaller than 5 nm. Encouraged by their structure and photoluminescence feature, they were used hereafter as intercalants or surface modifiers, in order to make fluorescent bentonite nanocomposites. Bentonite was used as negatively charged model of aluminosilicate and reacted with the positively charged CDs. Interestingly, CDs were found to intercalate bentonite as judged from XRD patterns, and TEM. Indeed, the basal distance of bentonite clay d(001) shifted from 1.2 nm to 2.9 nm, after bentonite modification using the prepared carbon dots; moreover the XRD pattern of BP-CDs recorded in the some regions show some additional diffraction peaks along with those for bentonite. The peaks centered at 2Ѳ =27 degree allocated to the facets of graphitic-like carbon, originated from the introduced carbon dots inside bentonite galleries. The prepared materials were characterized by XPS, FTIR and fluorescence analysis. The obtained results indicate that CDs were successfully intercalated inside bentonite matrix and found to be stable over time. The BP-CD nanocomposites were finally used as efficient hybrid platform for led removal with and extraction efficiently of 95% under light condition, room temperature under alkaline conditions and after only 10 min of reaction. </p>

<p>This work describes the preparation of novel fluorescent bentonite clay (BP), modified with carbon quantum dots nanomaterials (CDs), and its usage as lead removal platform, the CDs was prepared using graphitic waste serving as carbon source material via hydrothermal method, and the as obtained CDs were found to be fluorescent, in spherical shape, positively charged and smaller than 5 nm. Encouraged by their structure and photoluminescence feature, they were used hereafter as intercalants or surface modifiers, in order to make fluorescent bentonite nanocomposites. Bentonite was used as negatively charged model of aluminosilicate and reacted with the positively charged CDs. Interestingly, CDs were found to intercalate bentonite as judged from XRD patterns, and TEM. Indeed, the basal distance of bentonite clay d(001) shifted from 1.2 nm to 2.9 nm, after bentonite modification using the prepared carbon dots; moreover the XRD pattern of BP-CDs recorded in the some regions show some additional diffraction peaks along with those for bentonite. The peaks centered at 2Ѳ =27 degree allocated to the facets of graphitic-like carbon, originated from the introduced carbon dots inside bentonite galleries. The prepared materials were characterized by XPS, FTIR and fluorescence analysis. The obtained results indicate that CDs were successfully intercalated inside bentonite matrix and found to be stable over time. The BP-CD nanocomposites were finally used as efficient hybrid platform for led removal with and extraction efficiently of 95% under light condition, room temperature under alkaline conditions and after only 10 min of reaction. </p>