Silicon nitride (Si 3 N 4 ) nanowires have been prepared by carbothermal reduction followed by the nitridation (CTRN) of silica gel containing ultrafine excess carbon obtained by the decomposition of dextrose over the temperature range of 1200-1350• C. This innovative process involves repeated evacuation followed by purging of nitrogen gas so that the interconnected nanopores of the gel are filled with nitrogen gas prior to heat treatment. During heat treatment at higher temperatures, the presence of nitrogen gas in the nanopores of the gel starts the CTRN reaction simultaneously throughout the bulk of the gel, leading to the formation of Si 3 N 4 nanowires. The in situ generated ultrafine carbon obtained by the decomposition of dextrose decreases the partial pressure of oxygen in the system to stabilize the nanowires. The nanowires synthesized by this process are of ∼500 nm diameter and ∼0.2 mm length. The product was characterized by scanning electron microscope (SEM), energy dispersive x-ray analysis (EDX), x-ray diffraction (XRD) and infrared (IR) spectra.

nanoparticles of various size (~ 25.8 to 49.7 nm), obtained by a facile oxidation process using Ni(NO 3 ) 2 .6H 2 O, NaOH and sodium hypochlorite as precursor materials at various temperatures (0 o , 25 o , 50 o and 70 o C), is found to remove toxic Cr(VI) from aqueous solution (20 g L -1 ). The structural, morphological, surface charge and chemical compositions of the synthesized samples were characterized by XRD, TEM, zeta potential and EDX respectively. Adsorption capacity is found to be strongly dependent on the size and surface heterogeneity of the synthesized particles and the plausible mechanism for such significant adsorption efficacy is attributed to the sorbate -sorbent electrostatic interaction and shielding of Cr(VI) ions. The adsorption mechanism fits with the Langmuir isotherm model with maximum 60% Cr(VI) removal capacity (20.768 mg g -1 (calculated) and 20.408 mg g -1 (predicted from isotherms)) corresponding to Ni 2 O 3 nanoparticles, prepared at 70 0 C in 3 hours at room temperature. Thermodynamic parameters, obtained from fitting, demonstrate that the adsorption process being endothermic in nature follow pseudo-secondorder kinetic model. The spontaneity of the adsorption process gets reduced with increasing particle size. pH of the solution is observed to have a remarkable effect on the adsorption, giving maximum adsorption at pH = 6. . Please do not adjust marginsPlease do not adjust margins commercially used material for this purpose is the activated carbon or mesoporous carbon due to their high surface porosity. 8, 9 Apart from them, bio-adsorbents are often used as adsorbents in waste water treatment. 10-13 However, they have weak mechanical strength, poor separation capacity and hence they are not very effective in this field. Recently, alternative materials including various oxide based nanocomposites and nanostructure have been synthesized as potential adsorbent of heavy metal ions. 14,15 Thus, with the advancement of technology, newer materials with improved adsorption capacities are being developed.In this context, it has to be mentioned that metal oxides are known to have high adsorption capacity of toxic metals in nanodimensions. Iron and aluminium oxide have been identified to adsorb toxic substances from waste water effectively due to their high surface adsorption ability. [16][17][18] Among different transitional materials, developed so far, NiO has proven itself as an another promising material that shows potential application in battery electrodes, super-capacitors, smart windows, catalysis etc. [19][20][21][22] Nickel, being a transitional metal, possesses variable oxidation states, but most of them are found to be abundant in normal conditions. 23,24 In this context, it has to be mentioned that pseudo hydrate of Ni(III) oxide was reported but their anhydrous form was not observed due to easy transformation of them into NiO on heating. 25 On the other hand, it was established that these higher oxides may possess many interesting properties if obtained in anhydrous form.Accor...

Integration of biology with nanotechnology is now becoming attention-grabbing area of research. The antimicrobial potency of silver has been eminent from antiquity. Due to the recent desire for the enhancement of antibacterial efficacy of silver, various synthesis methods of silver in their nano dimensions are being practiced using a range of capping material. The present work highlights a facile biomimetic approach for production of silver nanoparticle being capped and stabilized by putrescine, possessing a diameter of 10-25 ± 1.5 nm. The synthesized nanoparticles have been analyzed spectrally and analytically. Morphological studies are carried out by high-resolution transmission electron microscopy and crystallinity by selected area electron diffraction patterns. Moreover, the elemental composition of the capped nanoparticles was confirmed by energy-dispersive X-ray spectroscopy analysis. A comparative study (zone of inhibition and minimum inhibitory concentration) regarding the interactions and antibacterial potentiality of the capped silver nanoparticles with respect to the bare ones reveal the efficiency of the capped one over the bare one. The bacterial kinetic study was executed to monitor the interference of nanoparticles with bacterial growth rate. The results also highlight the efficacy of putrescine-capped silver nanoparticles as effective growth inhibitors against multi-drug resistant human pathogenic bacterial strains, which may, thus, potentially be applicable as an effective antibacterial control system to fight diseases.

Nanostructured Aluminum Nitride (AlN) has been prepared by carbothermal reduction followed by nitridation (CTRN) of alumina gel over a temperature range 1200°C–1350°C and time period of 30 min to 3 h. Before heat treatment the gel is repeatedly evacuated and purged with ammonia. The nanopores of the gel are filled with ammonia which acts as a source of in situ nitrogen at heat‐treatment temperature. Dextrose also decomposes at the reduction temperature and generates ultrafine carbon. The stability diagram of the carbon saturated Al–N–O system is constructed and it shows that extremely low partial pressure of oxygen is required for the stability of AlN. The ultrafine carbon as well as hydrogen from the cracking of ammonia is not sufficient to create the extremely low partial pressure of oxygen required for the stabilization of AlN. So the sample is heat treated in charcoal boat in nitrogen atmosphere to achieve an extremely low partial pressure of oxygen required for the formation of AlN. The material has been characterized through XRD, FESEM, and HRTEM analyses. The spherical particle size of AlN is obtained ∼21 nm.

BACKGROUND: Leaching kinetics of the roasted (at 600• C) chromite overburden of Sukinda mines Orissa, India, was studied with optimized data generated through response surface methodology (RSM) coupled with Box-Behnken design (BBD). The effects of oxalic, citric and gluconic acid concentration (50-150 mmol L −1 ), reaction temperature (60 • to 80• C) and period (up to 3 h) on metal (nickel and cobalt) dissolution were examined.