Isolation and Characterization of Bioremediation Potent Microorganisms from Spectrophotometrically Analysed Heavy Metal (Cr and Cd)-Rich Tannery Effluent

ABSTRACT Microorganisms can become tolerant and highly efficient in degrading toxic heavy metals that cause environmental pollution. This study focuses on the isolation of hexavalent Cr and Cd (II)-resistant bacteria collected from tannery effluents. The isolation was conducted by spread plate method on Agar plates supplemented with their respective heavy metal salts (K 2 Cr 2 O 7 and CdCl 2 ). A total of ten isolates were screened of which, two were subjected to 16sRNA sequencing on the basis of the degree of their resistance to heavy metals. The bacteria, identified from the isolates, were Flavobacterium psychrophilum and Flavobacterium sp. ARSA-103, which can be used for bioremediation of metal-contaminated effluents

Influence of La3+ on structural, magnetic, dielectric, electrical and modulus spectroscopic characteristics of single phase CoFe2−xLaxO4 nanoparticles

In this work, we have studied the influence of La3+ substitution on structural, magnetic, dielectric, electrical and modulus spectroscopic characteristics of cobalt ferrite nanoparticles synthesized by starch-assisted sol–gel combustion method. The powder X-ray diffraction analysis confirms the formation of single-phase CoFe2−xLaxO4 (x = 0.00, 0.05, 0.10, 0.15, 0.20) spinel ferrite nanoparticles. Raman spectroscopy study also reveals the formation of single phase spinel ferrite crystal structure. The morphological feature of synthesized ferrite nanoparticle was observed by scanning electron microscopy that demonstrate formation of spherical nanoparticles with grain size 10–50 nm. The presence of constituent’s, i.e., Co, Fe and La were authenticated by energy dispersive X-ray analysis. The magnetic parameters are measured by employing vibrating sample magnetometer. The saturation magnetization decreases with La3+ substitution, whereas coercivity shows anomalous behaviour. Cation redistribution in spinel ferrite nanoparticles are confirmed by X-ray photoelectron spectroscopy. The variation of dielectric constant (ϵ′, ϵʺ), loss tangent (tanδ), ac conductivity (σ), electric modulus (M′, Mʺ) and impedance (Z′, Zʺ) as a function of La3+ ion concentration and frequency has been investigated. The dielectric constant and ac conductivity increases with increase of La3+ substitution, whereas dielectric loss tangent exhibits anomalous behaviour. The modulus spectra reveal two semicircles associated with grain and grain boundary effects. The cole–cole plots in modulus formalism show that the electrical characteristics contribute from both the grains and grain boundaries. Modulus spectra suggest that the distribution of relaxation times and conduction mechanism are influenced by La3+ ion substitution in cobalt ferrite nanoparticles. © 2017, Springer Science+Business Media New York.Ministry of Education, Youth and Sports of the Czech Republic-Program NPU I [LO1504