Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Sep 10;7(9):e07974.
doi: 10.1016/j.heliyon.2021.e07974. eCollection 2021 Sep.

Natural zeolite as a chromium VI removal agent in tannery effluents

Ana María Álvarez  1 , Darío Bolaños Guerrón  1   2 , Carolina Montero Calderón  1   3
Affiliations

Natural zeolite as a chromium VI removal agent in tannery effluents

Ana María Álvarez et al. Heliyon. .

Abstract

This study concerns Cr(VI) removal using zeolites in a batch system for tannery effluent. In the initial stage, natural zeolite (ZN) and synthetic zeolite (ZS) were characterized, obtaining a Si/Al ratio of 4.64 and 1.60, and with predominant clinoptilolite and faujasite phases, the surface area of 9.34 and 25.82 m2/g and cation exchange capacity of 84.05 and 188.72 meq/100 g, respectively. Subsequently, ZN and ZS were activated with HCl and NaOH. Through preliminary tests, with a solution of K2Cr2O7, it was determined that the highest Cr(VI) removal for both, ZN and ZS, was with NaOH activation, obtaining 82 and 56% removal, respectively. According to Ecuadorian regulations, the Cr(VI) concentration exceeds the maximum permissible limits on the tannery effluent. For this effluent, it was determined that the highest Cr(VI) removal, 45%, is obtained with 1 g of ZN activated with NaOH and 100 mL of effluent. With ZN-NaOH, removal tests were carried out in a fixed bed with 5, 10, and 20 g of natural zeolite. The natural zeolite also has chromium removal capacity in the bed system, achieving similar removals to those obtained in the batch experiments, but decreasing the treatment time. Thus, both natural and synthetic zeolites can remove Cr(VI) in tannery effluents, achieving this effluent with permissible limits.

Keywords: Activation; Adsorption; Tannery effluent; Zeolite.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
a) Percentage removal of Cr(VI) from tannery effluent with natural (ZN03) and synthetic (ZS01) zeolites. b) Evolution of Cr(VI) concentration as a function of removal time for the two zeolites studied. In both cases, concentrations of 0.6 mg/L and 1 g of zeolite were used.
Figure 2
Figure 2
Cr (VI) adsorption on activated natural zeolite (ZN) for different beds.
See this image and copyright information in PMC

References

    1. Oleas J., Jácome H. 2011. Boletín mensual de análisis sectorial de MIPYMES: Ropa de vestir de cuero para exportación, Quito.
    1. Naranjo Mantilla O.M., Loor Mendoza L.M. Universidad Tecnológica Indoamérica; 2017. Estudio de los residuos generados en el proceso de curtido y el impacto ambiental en la Empresa Curtiduría Hidalgo.http://repositorio.uti.edu.ec//handle/123456789/627
    1. Belay A.A. Impacts of chromium from tannery effluent and evaluation of alternative treatment options. J. Environ. Prot. (Irvine,. Calif). 2010;1:53–58.
    1. Suman H., Sangal V.K., Vashishtha M. Treatment of tannery industry effluent by electrochemical methods: a review. Mater. Today Proc. 2021
    1. Fouda A., Hassan S.E., Saied E., Hamza M.F. Photocatalytic degradation of real textile and tannery effluent using biosynthesized magnesium oxide nanoparticles (MgO-NPs), heavy metal adsorption, phytotoxicity, and antimicrobial activity. J. Environ. Chem. Eng. 2021;9:105346.

LinkOut - more resources