Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

A study on the utilization of rice husk as a biosorbent material for Cr (VI) removal from industrial effluent

Aniqa Naeem, Rida Batool

Institute of Microbiology and Molecular Genetics, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590, Pakistan;

For correspondence:- Rida Batool Email: rida.mmg@pu.edu.pk Tel:+924235952811

Accepted: 19 January 2021 Published: 28 February 2021

Citation: Naeem A, Batool R. A study on the utilization of rice husk as a biosorbent material for Cr (VI) removal from industrial effluent. Trop J Pharm Res 2021; 20(2):321-327 doi: 10.4314/tjpr.v20i2.15

© 2021 The authors.
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Abstract

Purpose: To study Cr (VI) removal from waste water using chromium-resistant bacterial strains in combination with rice husk.

Methods: Two strains of Exiguobacterium sp. resistant to chromium (VI) were applied in the present work. Rice husk (RH) was used as an agricultural waste for Cr (VI) removal. The elimination of Cr from the husk was chemically facilitated using hydrochloric, sulphuric and citric acids, as well as formaldehyde and potassium dihydrogen phosphate Investigation of optimum physical factors such as pH, temperature, shaking speed and biomass concentration on Cr (VI) removal was carried out using citric acid-processed rice husk alone, and in combination of bacterial strains. Fourier transform infra-red (FTIR) spectroscopy was performed to determine the contributions of different functional groups involved in Cr (VI) binding. Scanning electron microscopy (SEM) of treated and untreated RH was also performed.

Results: Citric acid-processed RH was most effective in the removal of chromate (97.3 %). The two bacterial strains combined with rice husk proved highly efficient in Cr (VI) removal from sterile and non-sterile industrial effluents. FTIR spectra showed the involvement of esters, amines and aliphatic functional groups in Cr (VI) binding, while SEM displayed the damaging effects of Cr (VI) on the surface of RH; however, bacterial inoculation minimized the damage.

Conclusion: Exopolysaccharides from Exiguobacterium strains and citric acid-processed rice husk demonstrated high efficiency for Cr (VI) removal. Hence, RH with these bacterial strains are potential biosorbents for control of heavy metal contamination arising from industrial effluents.

Keywords: Rice husk, Cr (VI), Contamination, Effluents, Exiguobacterium, Citrate