Polyethylene glycol-modified mesoporous zerovalent iron nanoparticle as potential catalyst for improved reductive degradation of Congo red from wastewater

Abstract

In this study, bare zero-valent iron nanoparticles (nZVI) have been modified using polyethylene glycol (PEG) of various molecular weight in a facile technique. The synthesized nZVI modified with PEG, M.W. of 600 and 6000 was denoted by nZVI-PEG₆₀₀ and nZVI-PEG₆₀₀₀, respectively, and compared their catalytic activity towards the reductive degradation of Congo red (CR) using NaBH₄.The existence of PEG layer surrounds the nZVI core was confirmed by several characterization tools, such as XRD, FTIR, FESEM and TEM. Herein, both nZVI-PEG₆₀₀ and nZVI-PEG₆₀₀₀ exhibited remarkable removal efficiencies of 89.6% and 99.2% within 14 min of reaction time. The optimum reaction parameters were found to be as follows: 0.2 g L⁻¹ catalyst dose and initial dye concentration of 2 × 10⁻⁵ molL⁻¹ etc. Kinetic studies of dye degradation were investigated which follow pseudo-1^st-order kinetics. The TOC analysis confirmed the complete mineralization of CR dye by nZVI-PEG₆₀₀₀ nanocatalyst. GCMS analysis of plausible degraded products was performed to elucidate a probable mechanistic pathway of CR degradation. Further, we have investigated the degradation of two anionic dyes mixture, i.e., CR and methyl orange (MO) using best catalyst, i.e., nZVI-PEG₆₀₀₀.

Keywords:

• Zerovalent iron nanoparticle (nZVI)
• polyethylene glycol modified
• Congo red
• reductive degradation
• catalytic activity

Acknowledgments

We would like to acknowledge Science & Technology and Biotechnology Department, Govt. of West Bengal (Project Memo No. 47 (Sanc.)/ST/P/S & T/15G17/2018 dt. 30.01.2019) and National Institute of Technology Durgapur for providing infrastructure and financial support to accomplish the work fruitfully. Department of Science and Technology under the SERB (N-PDF) sponsored project (No. PDF/2017/000390), Government of India was also acknowledged.

Conflicts of interest

The authors declare that there are no conflicts to declare.

Author’s contributions

Main manuscript writing: Ipsita Som, Perceived and designed the experiments: Ipsita Som and Mouni Roy, Execution of experiments: Ipsita Som Data collection and analysis: Ipsita Som Data interpretation: Ipsita Som and Mouni Roy, Guidance and funding: Rajnarayan Saha. All authors reviewed the manuscript carefully.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article and its Appendix.

Additional information

Funding

We would like to acknowledge Science & Technology and Biotechnology Department, Govt. of West Bengal (Project Memo No. 47 (Sanc.)/ST/P/S & T/15G17/2018 dt. 30.01.2019) and National Institute of Technology Durgapur for providing infrastructure and financial support to accomplish the work fruitfully. Department of Science and Technology under the SERB (N-PDF) sponsored project (No. PDF/2017/000390), Government of India was also acknowledged.