Kinetics of iron bioleaching using isolated leptospirillum ferriphilum: Effect of temperature

Abstract

This study was designed to investigate the effect of temperature on iron bioleaching kinetics using Leptospirillum ferriphilum. The bacteria were isolated and subjected to molecular characterization technique for confirming L. ferriphilum. Using the isolate, bioleaching data were collected in the temperature range of 298–318 K at an initial pH of 1.5 and 5% pulp density with an average particle size being 300 µm. The results of experiments concluded that leaching efficiency increases with temperature and maximum of 93.85% were observed after 20 days at 313 K. The bioleaching kinetics indicated that the maximum rate (rate constant: 0.1452 d1) was found in the experiment conducted at the optimum temperature, and the rate-controlling step was “diffusion through ash layer.” The activation energy was calculated to be 37.59 kJ/mol. From the thermodynamic study of the bioleaching system, ∆H˚ and ∆S˚ were found to be 0.7399 × 10−3 and 28.512 J/mol, respectively.