Non-Linear Error Functions Approach to Kinetic Study of Arsenic Removal from Soils using Proteus mirabili and Bacillus subtilis

Abstract

Kinetics of arsenic (As) removal by Proteus mirabilis and Bacillus subtilis were studied using the non-linear error functions approach. The two microorganisms (from soils samples obtained from a contaminated site in Amaonye-Ishiagu in Ebonyi State of Nigeria) were cultured and employed to deplete the metal ion from the contaminated soils. The experimental data were studied with four kinetic models namely pseudo first order, pseudo second order, simple Elovich, and intraparticle diffusion models using some non-linear error functions of root mean square error (RMSE), standard error of experiment (SEE), average relative error (ARE) and normalized standard deviation (NSD). Data from removal by both organisms were best described with pseudo first order model indicated by the ARE of minimum value of -1.8728 for Proteus mirabilis, and -2.1208 for Bacillus subtilis. These showed that the removal mechanism was reaction controlled as chemisorption was the rate limiting step.