Amine impregnated porous silica gel sorbents synthesized from water-glass precursors for CO2 capturing

In this work, porous silica gel-solid beads have been made from economically affordable water-glass precursors via sol-gel nano casting technique. A stable nanometric silica sol was prepared first from water glass and studied for surface potential and sol to gel transition. A free-flow, injectable gel was obtained upon aging the sol which was then assembled into spherical silica beads in a chemical bath. A surface area of 304.7m2g-1 was obtained for water glass derived silica gel beads. These gel beads were impregnated with 3-aminopropyltrimethoxysilane (APTMS) and polyethylenimine (PEI) active functional groups at different percentages for turning the gel beads as sorbents for CO2 gas adsorption. The effect of amine loading on the thermal stability, morphology as well as porosity was studied and was correlated with CO2 adsorption values. Depending upon the amount of amine loaded in the gel support CO2 uptake was found varied. These amine modified silica gel porous adsorbents showed CO2 adsorption capacity at temperatures as low as 100°C; samples modified with 15wt% PEI had CO2 adsorption capacity of 1.16mmolg-1 at 50°C. © 2015 Elsevier B.V

Synthesis and Efficient Phase Transfer of CdSe Nanoparticles for Hybrid Solar Cell Applications

Colloidal cadmium selenide (CdSe) nanoparticles capped by a short chain thiol ligand thioglycolic acid (TGA) were prepared in aqueous medium at 100∘C using sodium selenite as the selenium source. The prepared particles were efficiently transferred into organic phases through the partial ligand exchange process using 1-dodecanethiol (1-DDT). The FT-IR spectrum analysis shows the existence of the ligands on the surface of the nanoparticles in aqueous and organic phase through their characteristic modes. TEM analysis of the prepared samples reveals the size and crystalline nature of the particles. EDX analysis indicates the presence of respective elements in the resultant powdered sample. The possible mechanism of the phase transfer process was analysed. The resultant phase-transferred particles can efficiently be blended with a low band gap semiconducting polymer in a common solvent for active layer in hybrid solar cell fabrication. The results are discussed in detail.</jats:p

Soil fertility status and assessment of nutrient soil quality index of Ganasandra micro-watershed using GIS-based geospatial tool

Despite growing concerns about sustainable land management, limited studies have comprehensively evaluated soil fertility and spatial variability of nutrient soil quality at the micro-watershed level using geospatial techniques. The current research (2023-24) aimed to assess nutrient levels, soil health and the spatial variability of soil fertility within the Ganasandra micro-watershed, a component of the Naganahalli sub-watershed in Nagamangala taluk, Mandya district, Karnataka, using geospatial methods. Statistical evaluation of analytical data was performed using parameters such as range, mean and standard deviation. The soil was found to be slightly to strongly alkaline and nonsaline. Organic carbon levels ranged from low to medium; nitrogen and phosphorus availability were moderate; potassium was high and sulfur levels ranged from low to moderate. Diethylene triamine pentaacetic acid (DTPA) extractable micronutrients analysis indicated that half of the samples lacked sufficient zinc and iron, whereas copper and manganese concentrations were adequate. Shortages of N (nitrogen), P (phosphorus), S (sulphur), Zn (zinc) and Fe (iron) were identified as significant limitations to soil fertility. Principal component analysis (PCA) was employed to obtain the minimum data set (MDS) from the assessed soil parameters. Essential factors affecting soil quality include pH, organic carbon content and the availability of nitrogen and zinc. Three principal components with eigenvalues exceeding 1 accounted for 73.00 % of the overall variance. The soil quality index (SQI) ranged from 0.10 to 0.62. The study established that SQI, derived through grid sampling at a 320 m scale, successfully reflected spatial dependence through ordinary kriging and enabled the creation of thematic maps for soil management at the micro-watershed level. The SQI map showed that 46.63 % of the region was classified as low to very low soil quality, 22.79 % as medium and 31.32 % as high-quality categories

Comparison of natural farming with organic and conventional farming practices in green gram-paddy cropping system

Natural farming system (NFS) is one of the traditional cultivation methods to cut down production costs as well as dependence on external inputs. Being considered as an agro-ecologically diverse farming practice, it brings a host of ecological and social benefits. In order to know the sustainance of natural farming practice, field experiments were conducted at Zonal Agriculture Research Station (ZARS), V.C. Farm, Mandya, Karnataka, India for consecutive years (2019 to 2022). The experiments were laid out in a randomized complete block design comprised of five replication and four different farming practices as treatments namely, absolute control (AC), organic production system (OPS), Natural farming system (NFS) and recommended package of practice (RPP) of UAS, GKVK, Bengaluru. The pooled data of farming practices indicated significant variation in growth, yield and nutrient uptake, among farming practices significantly higher growth, yield and nutrient uptake were recorded with RPP both in green gram and paddy. The results of four years pooled data indicated that compared to conventional farming practice, natural farming recorded decreased yield of 134 (23.53%) and 3350 kg ha-1 (74.49%) in green gram and paddy, respectively. Also recorded 33.38% and 30.23% weed control efficiency by mulching in green gram and paddy, respectively. Based on this study we found that low nutrient demanding crops such as green gram (Pulses) are more suitable under natural farming compared high nutrient demanding crops viz., Paddy. Yields under natural farming can be enhanced by application of Farm yard manure and other natural sources for plant nutrition

Enhanced catalytic and supercapacitor activities of DNA encapsulated b-MnO2 nanomaterials

A new approach is developed for the aqueous phase formation of flake-like and wire-like b-MnO2 nanomaterials on a DNA scaffold at room temperature (RT) within a shorter time scale. The b-MnO2 nanomaterials having a band gap energy B3.54 eV are synthesized by the reaction of Mn(II) salt with NaOH in the presence of DNA under continuous stirring. The eventual diameter of the MnO2 particles in the wire-like and flake-like morphology and their nominal length can be tuned by changing the DNA to Mn(II) salt molar ratio and by controlling other reaction parameters. The synthesized b-MnO2 nanomaterials exhibit pronounced catalytic activity in organic catalysis reaction for the spontaneous polymerization of aniline hydrochloride to emeraldine salt (polyaniline) at RT and act as a suitable electrode material in electrochemical supercapacitor applications. From the electrochemical experiment, it was observed that the b-MnO2 nanomaterials showed different specific capacitance (Cs) values for the flake-like and wire-like structures. The Cs value of 112 F g�1 at 5 mV s�1 was observed for the flake-like structure, which is higher compared to that of the wire-like structure. The flake-like MnO2 nanostructure exhibited an excellent long-term stability, retaining 81% of initial capacitance even after 4000 cycles, whereas for the wire-like MnO2 nanostructure, capacitance decreased and the retention value was only 70% over 4000 cycles. In the future, the present approach can be extended for the formation of other oxide-based materials using DNA as a promising scaffold for different applications such as homogeneous and heterogeneous organic catalysis reactions, Li-ion battery materials or for the fabrication of other high performance energy storage device