Characterization of Mycobacterium sp. strain Spyr1 biomass and its biosorption behavior towards Cr(III) and Cr(VI) in single, binary and multi‐ion aqueous systems

Abstract

BACKGROUND: Mycobacterium sp. biomass was used for removal of Cr(III) and Cr(VI) species from aqueous systems. Experimental results were processed with different kinetic, isotherm and thermodynamic models. Studies of the effect of co-ions, biomass characterization and desorption were also undertaken. RESULTS: Cr(III) and Cr(VI) sorption on Mycobacterium sp. biomass followed Ho pseudo-second-order kinetics. The Langmuir isotherm model described the biosorption of both chromium species, whereas the Temkin isotherm model for Cr(III) and Hill-der Boer isotherm model for Cr(VI), respectively. Selectivity for Cr(III) and Cr(VI) biosorption was observed in binary mixtures with As(V), Mg +2 , Ca +2 , Cl − , SO 4 −2 , CO 3 −2 and PO 4 −3 ions from 5 to 200 mg L −1 and with Cu +2 , Ni +2 , Co +2 , Cd +2 , Mn +2 and Zn +2 ions up to 20 and 50 mg L −1 for Cr(III) and Cr(VI) respectively. In multi-ions systems, selectivity of both chromium species was achieved at a concentration of co-ions up to 10 mg L −1 . The thermodynamic parameters indicated the spontaneous and feasible nature of biosorption processes. Amine and carboxylic groups are mainly responsible in both chromium species binding, and the phosphate group is also involved in Cr(VI) sorption. Mycobacterium biomass exhibited almost the same removal efficiency up to five subsequent biosorption-desorption cycles for the two chromium species. CONCLUSION: Mycobacterium sp. biomass can be used as efficient and economic biomass for removal of both chromium species from contaminated water. M Aryal, M Liakopoulou-Kyriakides the presence of functional groups on biomass surface that may interact with the metal ions. In addition, desorption of chromium species and regeneration of biomass was also performed. MATERIALS AND METHODS Microorganism and growth conditionsMycobacterium sp. strain Spyr1 was isolated from Perivleptos (Epirus, North-West Greece), a creosote contaminated site, in which a wood preserving industry was operating for over 30 years. According to our previous publications, 7 -10 Mycobacterium sp. was cultivated in Luria-Bertani broth containing 1.0% tryptone, 0.5% yeast extract and 0.5% NaCl (Scharlau Chemie S.A., Barcelona, Spain), using an orbital incubator shaker at 180 rpm and 30 • C (Sanyo, MIR-153, Osaka, Japan). Cells were harvested by centrifugation (Kubota 5922, Tokyo, Japan) at 2000g for 20 min during the static phase of growth after 24 h of incubation, and autoclaved (Systec, Greiz, Germany) at 121 • C for 20 min before use. Moisture content was determined by drying a pre-weighted amount of the cells in an oven (Heraeus KT 5050, West Midlands, United Kingdom) at 100 • C for 10 h. Biosorption studies in single ion aqueous systemsReference Cr(III) and Cr(VI) solutions at 1000 mg L −1 were prepared from CrN 3 O 9 .9H 2 O and K 2 Cr 2 O 7 (Merck, Darmstadt, Germany). In order to determine the optimum pH, contact time and biomass concentration, initial Cr(III) and Cr(VI) concentration of 50 mg L −1 was used. Cr(III) and Cr(VI) biosorption on Mycobacterium sp....

Calcium alginate entrapped Eupatorium adenophorum Sprengel stems powder for chromium(VI) biosorption in aqueous mediums

“…The low R 2 values at different temperatures showed that this model can not be applied to predict the biosorption kinetics. However, Cr(VI) biosorption may be proceeded with physisorption mechanism [12].…”

“…The fitness of Cr(VI) biosorption data with low correlation coefficients as well as lower Q e,cal comparison to Q e,exp indicated that Cr(VI) biosorption on Eupatorium adenophorum- alginate beads did not follow Lagergren pseudo-first order reaction [12].…”

“…The comparatively low correlation coefficient values were observed with Ritchie, Sobkowsk and Czerwinski, and Blanachard pseudo second-order kinetic models respectively. Results indicated that biosorption process was not well described with these kinetic models [12].…”

“…The correlation coefficient values may imply the moderate applicability of Cr(VI) biosorption. Negative values of Gibbs free energy indicated the spontaneous nature and feasibility of Cr(VI) biosorption on Eupatorium adenophorum -alginate beads [12,45].…”

“…The bio-materials such as algae, fungi, yeast, bacteria, agricultural and industrial by-products have been studied for removal of heavy metals [1,8,11]. It is reported that biomaterials have a high potential for heavy metal removal [9,12]. Low cost biosorbents are becoming the focus of many researches [4].…”