Rajiv Giri

Poly-aromatic hydrocarbons (PAHs), such as benz[α]anthracene (BaA), are often released from cigarette smoke and pose a severe threat to public health. In this quest, several filtration techniques have been proposed for the elimination of these toxins, but the challenges remain the same in terms of low efficiency, high cost and complex manufacturing processes. Herein, we report a simple, cost-effective and reusable multiwalled carbon nanotubes (MWCNTs) membrane-based filter for enhanced removal (∼90%) of BaA from cigarette smoke. In terms of the excellent thermal stability of the MWCNTs membrane, the adsorbed PAHs could be removed simply by a thermolysis process. We believe that the present study may serve as inspiration for the design and development of high-performance fibrous materials for filtering and separation applications.

These days, textile industries pose a more significant threat to surface water and groundwater sources directly or indirectly by discharging wastewater containing various dyes and organic pollutants to these water sources. The phase-junction-engineered heterogeneous photocatalysis carried out by visible-light-driven semiconductor photocatalysts is opening a new window for the degradation of environmental organic pollutants. In this work, we have reported a one-step bottom-up hydrothermal synthesis of biphasic tungsten oxide (o/h-WO₃) and performed a photodegradation experiment under visible light irradiation for the efficient degradation of organic pollutants such as Methylene blue (MB) methyl violet (MV), respectively. The XRD, RAMAN, TEM, and UV-vis characterization techniques were used to investigate the structural, morphological, and optical properties of the as-synthesized o/h-WO₃. Moreover, the low calculated band gap ( ̴ 2.8 eV) and the anionic nature of o/h-WO₃ suggest it as an efficient visible-light-driven photocatalyst suitable for heterogeneous photocatalysis. The photodegradation experiment performed under visible light using o/h-WO₃ photocatalyst showed better degradation efficiency of 71% and 89% for MB and MV, respectively, in 100 min. The dyes followed first-order kinetics, and their kinetic rate constants were calculated using the Langmuir-Hinshelwood model. Furthermore, the recyclability study of the photocatalyst was also performed and discussed the underlying mechanism for the photodegradation of the organic dyes.

We report systematic studies of structural, microstructural and transport properties of (Hg_0.80 Sb_0.2-x Pb_x)Ba_2 Ca_2 Cu_3O_8+\delta (where x = 0.0, 0.05, 0.1, 0.15, 0.2) compounds. Bulk polycrystalline samples have been prepared by two-step solid-state reaction route at ambient pressure. It has been observed that simultaneous substitution of Sb and Pb at Hg site in oxygen deficient HgO_\delta layer of HgBa2Ca2Cu3O8+\delta cuprate high-Tc superconductor leads to the formation of Hg-1223 as the dominant phase. Microstructural investigations of the as grown samples employing scanning electron microscopy reveal single crystal like large grains embodying spiral like features. Superconducting properties particularly transport current density (Jct) have been found to be sensitive to these microstructural features. As for example (Hg0.80Sb0.05Pb0.15)Ba2Ca2Cu3O8+\delta compound which exhibits single crystal like large grains (~ 50 micrometer) and appears to result through spiral growth mechanism, shows highest Jct (~ 1.85 x 103 A/cm2) at 77K. A possible mechanism for the generation of spiral like features and correlation between microstructural features and superconducting properties have been put forward.