An experimental approach for the utilization of tannery sludge-derived Bacillus strain for biosorptive removal of Cr(VI)-contaminated wastewater

• Published in: Environmental science and pollution research international Vol. 28; no. 8; pp. 9864 - 9876
• Main Authors: Deepa, Arukula, Singh, Astha, Singh, Aakansha, Mishra, Brijesh Kumar
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-02-2021; Springer Nature B.V
• Subjects: Adsorption; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Bacillus; Biochemical tests; Biosorption; Chromium; Chromium - analysis; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Functional groups; Hexavalent chromium; Hydrogen-Ion Concentration; Ions; Kinetics; Metal concentrations; Morphology; pH effects; Process variables; Research Article; Retention time; RNA, Ribosomal, 16S; rRNA 16S; Sewage; Sludge; Surface chemistry; Tannery wastes; Waste Water; Waste Water Technology; Wastewater; Wastewater pollution; Water Management; Water Pollutants, Chemical - analysis; Water Pollution Control; Hexavalent chromium; Bacillus species strain; 16s rRNA gene sequencing; Tannery sludge; Cr(VI); Biosorption; Bacillus species strain DPAML065
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-11284-z

Biosorption efficacy of Bacillus strain
DPAML065
, isolated from the tannery sludge, was appraised for the removal of toxic hexavalent chromium (VI) ions from synthetic wastewater. Effects of the process variable on biosorbent surface by variation in pH, metal Cr(VI) concentration and retention time were examined using batch experiments. The isolated Bacillus strain biosorbent was studied for its morphology and surface chemistry through FE-SEM, EDX and FTIR. It discloses that, the reduction mechanism of Cr(VI) during the process is mainly attributed to precipitation in addition to the functional groups (such as –COOH, –OH, C–O, P=O) present on the cellular matrix of Bacillus. Biochemical tests and 16s rRNA sequencing were also performed to identify the biosorbent at the genus level. A 95% Cr(VI) removal efficiency was procured by Bacillus strain
DPAML065
biosorbent at pH 6, incubation period 24 h, 80 mg/L initial feed concentration and operational temperature 35 °C. Equilibrium behaviour of chromium binding follows the Langmuir isotherm model (
R
2
 = 0.968) with an adsorption capacity of 106.38 mg/g. Kinetic modelling disseminates that biosorption of Cr(VI) ions by Bacillus strain
DPAML065
obeyed pseudo-second-order model (
R
2
 = 0.984) rather than the pseudo-first-order model. Concisely, the results indicate that the Bacillus strain
DPAML065
is a potential, economically feasible and eco-friendly biosorbent which can be effectively used for removal of chromium (VI) from wastewater.