Pramod Kumar Rai

Synthesis, characterisation and evaluation of polydithiocarbamate resin supported on macroreticular styrene-divinylbenzene copolymer for the removal of trace and heavy metal ions

A new chelating resin was synthesised by the modification of styrene-divinylbenzene (2%) copolymer and incorporation of dithiocarbamate groups. The polydithiocarbamate resin was characterised by elemental analysis, thermal studies and IR studies. The analytical characteristics of the sorbent were established and optimum sorption conditions for Cu, Ni, Pb, Fe, As and Mn determined. The total sorption capacity of the resin was 37 mg g(-1) for Ni(II), 35 mg g(-1) for Cu(II), 29 mg g(-1) for Fe(III) and 23 mg g(-1) for Pb(II). The optimum pH for the removal of metal ions was 3-5 for Ni(II), 5 for Cu(II), 4 for Fe(III) and 4-5 for Pb(II). High sorption capacity was observed when compared with other conventional chelating polymers. The sorption kinetics was fairly rapid, as apparent from the loading half time t(1/2) values, indicating a better accessibility of the chelating sites.

Adsorption of diethylchlorophosphate on metal oxide nanoparticles under static conditions.

Nanoparticles of MgO, Al(2)O(3), CaO and SiO(2) were synthesized using aerogel route, and characterized by N(2)-BET, SEM, TEM, XRD, TGA and FT-IR techniques. Characterization indicated 2-75 nm diameter nanoparticles with 135-887 m(2)/g surface area and microporous-mesoporous characteristics. Prepared nanoparticles were tested for their adsorptive potential by conducting studies on kinetics of adsorption of diethylchlorophosphate under static conditions. The kinetic parameters such as equilibration constant, equilibration capacity, diffusional exponent and adsorbate-adsorbent interaction constant have been determined using linear driving force model and Fickian diffusion model. AP-MgO and AP-CaO showed the maximum (1011 mg/g) and minimum (690 mg/g) uptake of DEClP, respectively. All nanoparticles showed the values of diffusional exponent to be >0.5, indicating the diffusion mechanism to be anomalous. Hydrolysis reaction (identified using GC/MS technique) was found to be the route of degradation of DEClP.

Zero valent metal loaded silica nanoparticles for the removal of TNT from water

Silica nanoparticles with a surface area of 673.60 m2/g and particle size of 8-12 nm were prepared using aerogel process (AP) followed by super critical drying. Zero valent Fe, Co, Pt, and bimetallic Fe/Pt and Fe/Co were loaded using an incipient wetness impregnation technique and subsequent reduction. Scanning electron microscopy-energy dispersive X-ray (SEM-EDX) and transmission electron microscopy-energy dispersive X-ray (TEM-EDX) characterizations indicated fine dispersion of iron on AP-SiO2 +Fe system. Prepared nanoparticles were evaluated for the adsorptive removal of 2,4,6-trinitrotoluene (TNT) from water. Surface area normalized rate constant values indicated the adsorptive removal potential of prepared nanoparticles to be: AP-SiO2 + Fe/Co > AP-SiO2 + Fe > CM (commercial) SiO2 + Fe > AP-SiO2 + Co > AP-SiO2 + Fe/Pt > AP-SiO2 + Pt. Lower pH helped in accelerating the reactive removal of TNT on zero valent iron loaded silica. AP-SiO2 + Fe/Co system showed the maximum adsorption potential (74 mg/g) after five cycles.

Effect of inorganic and organic fertilizers along with Azotobacter on growth, yield and quality of Kinnow mandarin

A study was conducted during 2013 and 2014 on the effect of integrated use of inorganic and organic fertilizers (vermicompost) along with bio-inoculants on plant growth, yield and quality of Kinnow mandarin. Vegetative growth parameters like plant height and canopy volume showed maximum increase with cent per cent nitrogen through urea augmented with Azotobacter. Replacing 25 per cent of nitrogen in the form of vermicompost resulted in maximum number of fruits, fruit weight, fruit volume, fruit length and width and fruit yield. TSS, Total sugars (reducing and non-reducing) and ascorbic acid contents of the fruits improved with the integrated application of vermicompost along with inorganic fertilizers and biofertilizers.