| Summary: | Dried cell of a new strain, known as Acinetobacter baylyi, showed appropriate biological removal of Cr (VI) under
acidic condition. The adsorption parameters optimised were: biomass dose (2.0 g/L), initial pH (2.0), agitation speed (250 rpm),
initial Cr (VI) concentration (10–60 mg/L), temperature (30 C), and time (72 h). The experimental data in the 20–60 mg/L
Cr(VI) concentration range fitted well to the Langmuir isotherm (R2 = 0.9545, maximum capacity 11.96 mg/g) and pseudosecond-order adsorption model. The adsorption mechanism was best described by the Boyd plot and an intraparticle diffusion
model. TEM-EDX studies revealed that the noticeable chromium precipitates on bacterial surfaces and within the bacterial inner
portions after Cr (VI) adsorption. An XPS study recommended that this bacterium use carbonyl/hydroxy/carboxy groups on the
surface for adsorption of Cr (VI).
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