Thermal and spectroscopic properties of fluoride contaminated soil 21 o 32 ’ 41 ’’ N to 86 o 48 ’ 55 ’’ E of Odisha, India

Abstract

Abstract The primary purpose of this investigation is to know thermal properties of soil and extraction of fluoride and its quantitative determination. This study was also carried out to know the fluoride contamination after acid treatment of soil. The specific heat capacity (CP) is measured in heat flux DSC (Differential Scanning Calorimetry) at the heating rate of 2 K min− 1 in an N2 atmosphere using the sapphire standard. The elemental analysis, 19F NMR, TG-DTA, and ATR-IR are carried out for the determination of composition in soil. Fluoride ion is determined using ion selective electrode. This ATR-IR spectrum of soil indicates that Fe, Al and Si, containing fluoride minerals are present in the soil. The CP of this fluoride-contaminated soil is found to be less at higher temperatures and greater at room temperature as compared to other soils. The soil is contaminated with fluoride, confirmed using 19F NMR measurement. The optical band gap calculation from Kubelka–Munk relation indicates that soil is highly insulator. The reflection characteristic is confirmed by Diffuse Reflectance Spectrum (DRS). The concentration of fluoride in 1kg of soil is 12.79 g. as fluoride minerals.The less endothermic behaviour of soil at high temperatures and high endothermic at room temperature further makes the weather extremely hot in summer and cold in winter. The soil still contaminated with fluoride minerals after acid treatment. The minerals release fluoride ion in alkaline medium that is measured using ion selective electrode.