NOPR Community:

Oxidation behviour of sol-gel zirconia coated 9Cr-1Mo ferritic steel in air atmosphere

2016-11-15T11:12:02Z

Title: Oxidation behviour of sol-gel zirconia coated 9Cr-1Mo ferritic steel in air atmosphere Authors: Singh, I B; Ruhi, G; Modi, O P; Singh, M Abstract: The oxidation behaviour of sol-gel derived zirconia coated 9Cr-1Mo ferritic steel has been examined at 700-900°C in air atmosphere. X-ray elemental mapping of the coated surface detected a continuous band of zirconium and oxygen, attributing to the presence of zirconia coating of around 2 µm in thickness. Oxidation kinetics indicates that the oxidation rate constant of the coated substrates decreases an order of magnitude lower as compared to uncoated substrates. Measurement of a noticeable increase in activation energy of the coated surface is further evidence towards the improvement of the oxidation resistance of the steel after coating development. Microstructural examination through field emission scanning microscope (FE-SEM) of the oxidized substrates show the presence of comparatively thin, less porous and compact scale at the coated surface than uncoated surface. Page(s): 533-537

Column mode removal of copper through physically entrapped algal bioadsorbents

2016-11-15T11:08:00Z

Title: Column mode removal of copper through physically entrapped algal bioadsorbents Authors: Ranjith, L; Shukla, S P Abstract: A polyurethane column with physically entrapped algal materials has been designed and tested for copper removal from aqueous medium. The performance of the column is assessed on the basis of the parameters viz. bio-removal efficiency, metal sequestered in the column and bio-sorption capacity. The findings show that the combination of calcium alginate and S. platensis exhibit highest bio-removal efficiency (38.42%) for Cu(II) in the concentration range 5-20 mg L^-1. The maximum bio-sorption capacity (80.30 mg/g) is recorded for a mixture of calcium alginate and S. platensis after 60 min treatment time. FTIR analysis of algal adsorbents show that the adsorption efficiency depended on the availability of negatively charged groups such as carboxylic and hydroxyl groups. The study concluded that the algal compounds and dried biomass of S. platensis are effective bio-adsorbents for the removal of Cu(II) from water. Page(s): 527-532

Antibacterial activity of biostabilized silver nanoparticles

2016-11-15T11:02:21Z

Title: Antibacterial activity of biostabilized silver nanoparticles Authors: Rochlani, Kavita; Vadakkekara, Raji; Chakraborty, Mousumi; Dasgupta, Sumita Abstract: Bioactive silver nanoparticles (Ag NPs) have been synthesized by reacting aqueous solution of silver nitrate (AgNO₃) with plant extracts which act as reducing and stabilizing agent at ambient temperature. The bio-reduction behaviour of extracts of different parts of plant such as Plumbagozeylanica, Cassia tora, Kalanchoegastonis-bonnieri, Euphorbia milii, Tridaxprocumbens, Nyctanthesarbor-tristis, Psidiumguajava and Lantana camara in the synthesis of silver nanoparticles have been studied. The size and size distribution of prepared NPs have been investigated employing UV-vis absorption spectrophotometer, Dynamic light scattering (DLS) and Transmission electron microscopy (TEM). Dispersion destabilization of NPs is detected by Turbiscan. Different parameters such as stirring effect, reaction time, temperature, silver nitrate concentration and amount of plant extract have been studied to find out the optimum condition for synthesis of Ag NPs. Furthermore, biologically synthesized Ag NPs are tested for their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis. Page(s): 520-526

Visible-light induced photocatalytic mineralization of methylene green dye using BaCrO₄photocatalyst

2016-11-15T10:58:22Z

Title: Visible-light induced photocatalytic mineralization of methylene green dye using BaCrO₄photocatalyst Authors: Pare, Brijesh; Solanki, Vijendra Singh; Gupta, Premlata; Jonnalgadda, S B Abstract: The photocatalytic degradation of a hazardous methylene green dye solution has been reported. The effects of various parameters such as catalyst loading, pH, initial concentration of the dye, concentration of H₂O₂ and K₂S₂O_8, concentration of NaCl and Na₂ CO₃, N₂ and O₂ bubbling, and intensity of light on decolourization have been investigated. The photocatalytic removal of methylene green dye and its degradation efficiency has been evaluated by determination of reduction in the chemical oxygen demand (COD) from 440 mg/L to 5 mg/L and increase in CO₂ values from 9 mg/L to 212 mg/L in 7 h. A decrease in pH and increase in conductivity of solution is observed with increase in the extent of mineralization. The extent of decolourization has been discussed in terms of the Langmuir-Hinshelwood model. The rate of decolourization of dye is recorded with respect to the change in the intensity of absorption peak in visible region. The prominent peak at λ_max, i.e., 650 nm decreases gradually and finally disappears indicating that the dye is decolourized. Similarly the peak in the UV region at 300 nm decreases with the passage of time, thereby confirming the complete mineralization of the dye. Page(s): 513-519

NOPR Community:

Oxidation behviour of sol-gel zirconia coated 9Cr-1Mo ferritic steel in air atmosphere

Column mode removal of copper through physically entrapped algal bioadsorbents

Antibacterial activity of biostabilized silver nanoparticles

Visible-light induced photocatalytic mineralization of methylene green dye using BaCrO4 photocatalyst

Visible-light induced photocatalytic mineralization of methylene green dye using BaCrO₄photocatalyst