Synthesis and characterization of SnO2/rGO nanocomposite for an efficient photocatalytic degradation of pharmaceutical pollutant: Kinetics, mechanism and recyclability.

The SnO2 and SnO2/rGO nanostructures were successfully synthesized using the facile hydrothermal synthesis technique. The prepared nanostructures were well studied using different techniques such as XRD, XPS, UV-DRS, FT-IR, EDX, SEM and HR-TEM analysis. The crystalline nature of SnO2 and SnO2/rGO was confirmed by the XRD technique. The formation of highly pure SnO2 and SnO2/rGO nanostructures was confirmed by EDX analysis. The morphological results show the good agglomeration of several spherical nanoparticles. The optical properties were studied through the UV-DRS technique and the bandgap energies of SnO2 and SnO2/rGO are estimated to be 3.12 eV and 2.71 eV, respectively. The photocatalytic degradation percentage in presence of SnO2 and SnO2/rGO against RhB was found to be 96% and 98%, respectively. The degradation of TTC molecules was estimated as 90% and 88% with SnO2/rGO and SnO2, respectively. The degradation of both RhB and TTC molecules was well suited with the pseudo-first-order kinetics. The results of successive experiments clearly show the enhancement in the photocatalytic properties in the SnO2/rGO nanostructures.

White LED active α-Fe2O3/rGO photocatalytic nanocomposite for an effective degradation of tetracycline and ibuprofen molecules.

The formation of phase pure magnetically separable α-Fe2O3 and α-Fe2O3/rGO nanostructures were achieved through a simple hydrothermal technique. The properties of synthesized materials were investigated through different analytical techniques. The formation of phase pure FO and FO/rGO nanostructures were confirmed by XRD analysis with crystallite size of about ∼42 nm and ∼65 nm, respectively. The morphological analysis reveals the formation of sphere-like nanoparticles with high agglomeration. The UV-DRS analysis clearly shows the enhanced visible-light activity of FO/rGO nanoparticles. The BET analysis revealed the mesoporous property of FO/rGO nanocomposite. The enhancement in the photoinduced charge transfer process is observed after including rGO nanoparticles with FO. The photocatalytic efficiency of nanomaterials was analyzed using tetracycline and ibuprofen as model organic pollutants under white LED irradiation. The enhanced photocatalytic degradation ability of FO/rGO nanocomposite is studied against both tetracycline and ibuprofen molecules.

CuO/C nanocomposite: Synthesis and optimization using sucrose as carbon source and its antifungal activity.

The synthesis of bioactive CuO/C nano composite using sucrose as a capping agent is achieved through simple green approach via Response Surface Methodology. The synthesis process was done in a green environment which prevents aggregation of sucrose and promotes nanoparticles formation. The innovative approach produces sucrose as a carbon source mediated copper oxide nanocomposites (CuO/C nanocomposite) with the particle size of 50 nm. Additionally, the produced CuO/C nanocomposite were characterized using microscopic techniques like SEM, TEM and spectroscopic techniques like UV-vis and X-ray diffraction. The antifungal activities of CuO/C nanocomposite were tested against Aspergillus niger and Aspergillus flavus species. At 1000 ppm of CuO/C nanocomposite, it showed 70% restraint on A. flavus and 90% hindrance on A. niger. The fungal inhibition mechanism of bioactive CuO/C nanocomposite was discussed in this research article. The particular high antifungal performance of CuO/C nanocomposite was found against Aspergillus niger while compare to Aspergillus flavus fungal strain.

Kinetics of thermal softening of cassava tubers and rheological modeling of the starch.

Cassava or tapioca (Manihot esculenta Crantz) tubers having high amount of carbohydrate are utilized after boiling or processing into starch and flour. Textural properties of raw and cooked tubers depend on variety, maturity, growing environment, physico-chemical and starch properties. Starch is used in food preparations as gelling and thickening agent, stabilizer and texture modifier. This study aims at analyzing and modeling the textural, dynamic rheological and gelatinization properties of selected cassava varieties. The thermal softening behavior was analyzed by linear regression and fractional conversion techniques, rheological properties of the gelated starch by Maxwell and power law models. The varieties were classified based on their physico-chemical, texture profile, rheological and gelatinization properties by multivariate analysis. The textural, rheological and gelatinization properties were significantly affected by the varieties (p < 0.05). Thermal softening of tubers was modeled by dual mechanism first order kinetic model with rate constant values ranging from 0.081 to 0.105 min(-1). Linear regression models with extremely good fit were obtained to explain the relationship between the degree of cooking and relative firmness. The dynamic spectra of the gelated starch showed the characteristics of concentrated biopolymer dispersion and described using Maxwell and power law model. The results showed that textural, rheological and gelatinization properties varied considerably among the varieties and besides the physico-chemical properties, interaction between them and structural make up of the tuber parenchyma had a great influence on cooking quality and rheological properties.