In the present investigation, dead bacterium biomass
Streptomyces rimosus
was used
as an inexpensive and efficient biosorbent for Cr (III) removal from aqueous solution. The bacterial
biomass was treated with 0.1 M NaOH. Sorption level of 65 mg/g was observed at pH 4.8 while
precipitation effect augmented this value at higher pH range. Chromium desorption increased with
decreasing desorption agents pH (including HCl and H
2SO
4) to a maximum value of 95% at
approximately zero pH. Langmuir, Freundlich and Temkin models were applied to describe the
biosorption isotherm of the metal ions by Streptomyces rimosus biomass. Langmuir model fitted the
equilibrium data better than the Freundlich isotherm. Maximum metal uptake q
max was observed as
83.33 mg g
”1 indicate good biosorbents than other biomass. Experimental data were also tested in
terms of biosorption kinetics using fractional power, Elovich, pseudo-first order and pseudo-second
order rate expressions. The results showed that the biosorption processes followed well pseudosecond-
order kinetics and the intra-particle diffusion is not the rate-limiting step for the whole
reaction.