Novel continuous single-step synthesis of nitrogen-modified TiO2 by flame spray pyrolysis for photocatalytic degradation of phenol in visible light

A novel rapid and continuous process has developed for the synthesis of nitrogen-doped TiO₂ (N-TiO₂) with flame spray pyrolysis (FSP) method. The nitrogen incorporation into TiO₂ was achieved by a facile modification (addition of dilute nitric acid) in the precursor for the synthesis. The catalysts were characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The doping of nitrogen into the TiO₂ was confirmed by X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray (EDX) spectroscopy. The UV–vis spectra of the modified catalysts (with primary N source) exhibited band-gap narrowing for 4N-TiO₂ with band gap energy of 2.89 eV, which may be due to the presence of nitrogen in TiO₂ structure. The introduction of secondary N-source (urea) into TiO₂ crystal lattice results in additional reduction of the band gap energy to 2.68 eV and shows a significant improvement of visible light absorption. The N-TiO₂ nanoparticles modified by using secondary N-source showed significant photocatalytic activity under visible light much higher than TiO₂. The higher activity is attributed to the synergetic interaction of nitrogen with the TiO₂ lattice. The lowering of the band-gap energy for the flame made N-doped TiO₂ materials implies that the nitrogen doping in TiO₂ by aerosol method is highly effective in extending the optical response of TiO₂ in the visible region. The nitrogen atomic percentage has increased monotonically (0.09%–0.15%) with the increase in primary nitrogen source (nitric acid), and significantly boosted to 0.97% when secondary nitrogen source (urea) was introduced. The highest rate of phenol degradation was obtained for catalysts with secondary N source due to increase in N content in the catalyst.     

Enhanced separation of Toluene and Xylene through surface modified porous carbon matrix

Aromatics that are present in the feed of the Claus sulfur recovery process are well known to poison the catalyst and hence continued efforts are being made within the scientific community to remove them. In this context, the present work attempts to develop superior adsorbents in comparison with contemporary adsorbents for removal of toluene and m-xylene. In a bid to improve adsorption properties, nitrogen-containing surface functional groups were successfully introduced onto porous carbon by minimizing pore damage while maximizing nitrogen content. The surface modified adsorbents were subjected to gas phase adsorption of toluene and m-xylene at 45°C to generate the adsorption isotherms. Toluene adsorption capacity for the modified adsorbent was observed to have increased by approximately 30% at pressure of about 20 mbar and m-xylene by about 10% at about 22 mbar. Several orders of magnitude increase in adsorption capacity was observed for both aromatics at pressures less than 10 mbar. Such high adsorption capacity have not been reported in literature and could potentially favorably alter the economics of aromatics removal in gas processing. Regenerability of nitrogen doped adsorbent was ensured through cyclic adsorption/desorption tests. The adsorption isotherms as well as the kinetics of adsorption were modelled.     

Ply level uncertainty effects on failure curves and optimal design of laminated composites using directional bat algorithm

The present study investigates the effect of both ply level material uncertainty and ply angle uncertainty on the failure envelope, strength characteristics and design of laminated composite. Multiple failure envelopes and distributions of the strength parameters are obtained for Tsai-Wu and maximum stress criteria using Monte Carlo simulation. A newly developed directional bat algorithm (dBA) is then used to perform the constrained design optimization of laminated composite for the first time while considering uncertainty effects. The effect of ply level uncertainty on failure envelopes and the corresponding optimal design of laminated composite structures is thus quantified.     

Discrimination of maize crop with hybrid polarimetric RISAT1 data

Microwave remote sensing provides an attractive approach to determine the spatial variability of crop characteristics. Synthetic aperture radar (SAR) image data provide unique possibility of acquiring data in all weather conditions. Several studies have used fully polarimetric data for extracting crop information, but it is limited by swath width. This study aimed to delineate maize crop using single date hybrid dual polarimetric Radar Imaging Satellite (RISAT)-1, Fine Resolution Stripmap mode (FRS)-1 data. Raney decomposition technique was used for explaining different scattering mechanisms of maize crop. Supervised classification on the decomposition image discriminated maize crop from other land-cover features. Results were compared with Resourcesat-2, Linear Imaging Self Scanner (LISS)-III optical sensor derived information. Spatial agreement of 91% was achieved between outputs generated from Resourcesat-2, LISS-III sensor and RISAT-1 data.     

Metal Species–Encapsulated Mesoporous Silica Nanoparticles: Current Advancements and Latest Breakthroughs

Despite their advantageous morphological attributes and attractive physicochemical properties, mesoporous silica nanoparticles (MSNs) are merely supported as carriers or vectors for a reason. Incorporating various metal species in the confined nanospaces of MSNs (M‐MSNs) significantly enriches their mesoporous architecture and diverse functionalities, bringing exciting potentials to this burgeoning field of research. These incorporated guest species offer enormous benefits to the MSN hosts concerning the reduction of their eventual size and the enhancement of their performance and stability, among other benefits. Substantially, the guest species act through contributing to reduced aggregation, augmented durability, ease of long‐term storage, and reduced toxicity, attributes that are of particular interest in diverse fields of biomedicine. In this review, the first aim is to discuss the current advancements and latest breakthroughs in the fabrication of M‐MSNs, emphasizing the pros and cons, the confinement of various metal species in the nanospaces of MSNs, and various factors influencing the encapsulation of metal species in MSNs. Further, an emphasis on potential applications of M‐MSNs in various fields, including in adsorption, catalysis, photoluminescence, and biomedicine, among others, along with a set of examples is provided. Finally, the advances in M‐MSNs with perspectives are summarized.