Environmental Pollution and Protection

8

Authors: Saumya Srivastava, Arvind Kumar Shukla

Black gram (Vigna mungo L. cv Shekhar-2) was grown in refined sand with complete nutrition (control) and at 0.25 mM each of As, Cd, Co, Cr and Pb. Toxicity of heavy metals on biomass, followed the order: As> Cr> Cd> Co> Pb. Plants treated with As could not survive and wilted within 1 week of supply. Pigments and protein in Cr and Co treated plants were significantly reduced as compared to control. Lipid peroxidation, peroxidase and superoxide dismutase was higher in Cr and Co than Cd and Pb treated plants. Results show that black gram is extremely sensitive to arsenic followed by chromium. Cobalt and cadmium are also toxic for growth of Vigna mungo, however, Co mainly disturbs the metabolism of the plant. Lead was least toxic for growth of black gram.

14

Authors: Moumita Sharma, Dr Papita Das, Prof. Siddhartha Datta

In this paper a comparative study had been performed by green synthesis of silver nanocomposites using neem leaf extract (Azadirachta indica) and basil leaf extract (Ocimum sanctum). The green synthesis of silver nanocomposites (soil-AgNP) was used since it is efficient as well as cost effective. The nanocomposites were characterized by color change, UV-VIS Spectroscopy, XRD (X-Ray Diffraction Analysis), SEM (Scanning Electron Microscopic Analysis), FTIR (Fourier Transform Infrared Spectroscopic Analysis) and TEM (Transmission Electron Microscopic Analysis). Change in the color of the solution of leaf extract and silver nitrate to dark brown corresponds to the Plasmon absorbance of the silver nanoparticles. The SEM, TEM and FTIR studies also confirmed the formation of silver nanocomposites. Various experiments were carried out by varying the properties like adsorbent dose, time, temperature, shaker speed, pH and concentration. Adsorption isotherms, thermodynamics and kinetics were also evaluated. It was noticed that the silver nanocomposite from basil leaf was providing around 98% removal of Gentian Violet dye which was relatively higher than both neem leaf composite as well as soil.