National Chemical Laboratory

About: National Chemical Laboratory is a facility organization based out in Pune, Maharashtra, India. It is known for research contribution in the topics: Catalysis & Nanoparticle. The organization has 8891 authors who have published 14837 publications receiving 387600 citations.

Pore surface engineering in porous, chemically stable covalent organic frameworks for water adsorption

Abstract: Herein, we have explored the possibility of a class of covalent organic frameworks (COFs) as water adsorbing materials. We have selected, synthesized 12 chemically stable functionalized Schiff base COFs and thoroughly studied their water uptake behaviour. Further, a deep understanding was developed with these COFs towards the effects of condensation pressure of water and hydrophilic/hydrophobic groups present in the COF pores on water absorption capacity and ultimately, their recyclability. Among all reported COFs, TpPa-1 shows the highest water uptake of 30 wt% (368 cm3 g−1; 17 mmol g−1) at P/P0 = 0.3, which is also comparable with the recently reported carbon materials and few well known MOFs. This study also reveals that the overall water uptake of COFs can be tuned systematically based on chemical functionality and pore size in a wider window of relative pressures.

Combustion Synthesis of Triangular and Multifunctional ZnO1−xNx (x ≤ 0.15) Materials

Abstract: The preparation and characterization of multifunctional ZnO1−xNx (x ≤ 0.15) via a simple solution combustion method is reported. ZnO1−xNx exhibits visible light absorption, thermal stability, nanometer-/micrometer-sized triangular particles, and catalytic properties. X-ray diffraction studies of ZnO1−xNx demonstrate that the lattice oxygen in ZnO is replaced by nitrogen without any major change in the wurtzite structure; however, charge compensation occurs, because of interstitial Zn atoms, as well as oxygen vacancies. Microscopic studies reveal the dominance of nanometer- and micrometer-sized triangles of ZnO1−xNx. UV−visible and Raman spectra indicate a midgap state, derived from N 2p states, and direct Zn−N interaction, respectively. Secondary ion mass spectrometry studies show the presence of N and ZnN species in the bulk and support the direct Zn−N interaction. Electron paramagnetic resonance (EPR) studies indicate the presence of a small amount of defects. Photocatalytic decomposition of rhodamine B...

Production, Purification and Partial Characterization of 1,4-β-Glucosidase Enzymes from Sporotrichum pulverulentum

Abstract: The production of 1,4-β-glucosidase activity by the rot fungus Sporotrichum pulverulentum has been investigated. It was found that cellobiose or cellulose is necessary to cause induction. With cellobiose as sole carbon source only cell-wall-bound enzymes are produced. For extracellular excretion cellulose seems to be a necessary carbon source. The purification procedures, for purification of enzyme activity in the culture solution, involve the following steps: (a) ultrafiltration, (NH4)2SO4 precipitation and dialyses; (b) preparative slab gel isoelectric focusing I, pH range 3–10; (c) phenyl-Sepharose chromatography; (d) preparative slab gel isoelectric focusing II, pH range 3–5. On the phenyl-Sepharose column the β-glucosidase activity was associated with two separable enzyme peaks, enzyme A and B. When these enzymes were subjected to further purification on preparative isoelectric focusing II, enzyme A was split into two peaks, A1 and A2, and enzyme B was split into three peaks, B1, B2 and B3. The significance of the separations is discussed. The isoelectric points of all the enzymes have been determined and found to vary between 4.52 to 5.15. The molecular weights, determined by dodecylsulphate-polyacrylamide gel electrophoresis, vary between 165000 and 182000. The kinetic constants Km and Ki have been determined for enzyme A and B as well as for the cell-bound β-glucosidase activity. Km for cellobiose was for both enzyme A and B higher than Km for p-nitrophenyl β-d-glucoside. Km/Ki of the free enzymes for gluconolactone is approximately 2500 (enzyme B) to 13000 (enzyme A) with cellobiose as substrate.