Exploitation of green synthesized chromium doped zinc oxide nanorods (NRs) mediated by flower extract of Rhododendron arboreum for highly efficient photocatalytic degradation of cationic dyes Malachite green (MG) and Fuchsin basic (FB)

Abstract

In this work, green method to synthesize chromium-doped zinc oxide (ZnO) nanorods (NRs) using an aqueous flower extract from Rhododendron arboretum is explored. Herein, chromium-doped ZnO NRs were prepared with different amount of chromium doping, varied as 2–10%. The green synthesized products underwent substantial analysis through X-ray diffraction (XRD), spectroscopic such as ultraviolet spectroscopy(UV-Vis) and scanning electron microscopy (SEM) methods. All samples were found to have hexagonal wurtzite ZnO, with average particle sizes of 52.41, 56.6, 54.44, 53.05, and 56.99 nm, respectively, for 2, 4, 6, 8, and 10% chromium doping in ZnO NRs. The Cr-doped ZnO NRs exhibited remarkable photocatalytic degradation activity of cationic dyes under UV-light, i.e., Malachite Green and Fuchsin Basic with degradation of 99.604 and 99.881%, respectively in 90 min. The reusability tests for these green synthesized Cr-doped ZnO NRs have also been carried out, showed 9–11 cycles with 85% of degradation efficiency. In addition, the Cr-doped ZnO NRs exhibited high selectivity for cationic dyes when experiments against mixture of dyes were performed. Photodegradation kinetics followed the pseudo-first-order model. The flower-extract-stabilized chromium-doped ZnO NRs demonstrated high photocatalytic activity toward malachite green and fuchsin basic dyes, potential material for pollution remediation.

HIGHLIGHTS

1. Cr-doped ZnO NRs by green method using flower extract of Rhododendon arboretum were prepared for the first time under ambient reaction conditions.

2. Effect of Dopant i.e. Cr on Photocatalytic activity have been exploited.

3. Selective photocatalytic degradation of cationic dyes i.e. MG, and FB has been achieved in 60–90 minutes.

4. Optimization of reaction condition and various parameters has also been carried out.

5. Recyclability of Cr-doped ZnO NRs was also evaluated and were found to be reusable for 11 cycles for degradation.

Keywords:

• Doping
• photocatalyst
• Rhododendron arboreum
• wastewater treatment
• ZnO NRs

Acknowledgment

The authors Santosh Kumar (SK) and Rajesh Kumar (RK) are thankful to the Department of Environment Science and Technology, Himachal Pradesh, India for providing financial support under “Specific Research and Development project 2021-2022” vide letter no. (F)5-1/2021-3018. SK is also thankful to NMHS (National Mission on Himalayan Studies) for funding support for this work with vide letter no.NMHS/2022-23/SG81/01/280.

Author contributions

Tanuj: writing-original draft, formal analysis, Rajesh Kumar: writing-original draft, formal analysis, Santosh Kumar: writing original draft, formal analysis, Neerja Kalra: Formal Analysis Subhash Sharma: Formal analysis, Amritpal Singh: Formal analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

There is no data used in this research article.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by Department of Environment Science and Technology, Himachal Pradesh, India and NMHS (National Mission on Himalayan Studies), Almora, India.