Plant Extract Induced Biogenic Preparation of Silver Nanoparticles and Their Potential as Catalyst for Degradation of Toxic Dyes

Khalida Naseem,Muhammad Zia Ur Rehman,Awais Ahmad,Deepak Dubal,Tahani Algarni

doi:10.3390/coatings10121235

Abstract

This study focusses on the synthesis of silver nanoparticles (Ag-nPs) by citrus fruit (Citrus paradisi) peel extract as reductant while using AgNO3 salt as source of silver ions. Successful preparation of biogenic CAg-nPs catalyst was confirmed by turning the colorless reaction mixture to light brown. The appearance of surface Plasmon resonance (SPR) band in UV-Vis spectra further assured the successful fabrication of nPs. Different techniques such as FTIR, TGA and DLS were adopted to characterize the CAg-nPs. CAg-nPs particles were found to excellent catalysts for reduction of Congo red (CR), methylene blue (MB), malachite green (MG), Rhodamine B (RhB) and 4-nitrophenol (4-NP). Reduction of CR was also performed by varying the contents of NaBH4, CR and catalyst to optimize the catalyst activity. The pseudo first order kinetic model was used to explore the value of rate constants for reduction reactions. Results also interpret that the catalytic reduction of dyes followed the Langmuir–Hinshelwood (LH) mechanism. According to the LH mechanism, the CAg-nPs role in catalysis was explained by way of electrons transfer from donor (NaBH4) to acceptor (dyes). Due to reusability and green synthesis of the CAg-nPs catalyst, it can be a promising candidate for the treatment of water sources contaminated with toxic dyes.

Highlights

Different environmental pollutants such as toxic dyes have been identified as threats because these dyes are harmful for humans and aquatic life [1,2]
Bands appearing at 694.23 cm−1 in both plant extracts and CAg-nPs particles are an indication of the presence of aromatic hydrocarbons [39]
This study presents the ecofriendly biogenic synthesis of CAg-nPs by an aqueous peel extract of Citrus paradise

Summary

Introduction

Different environmental pollutants such as toxic dyes have been identified as threats because these dyes are harmful for humans and aquatic life [1,2] Discharge of these dyes containing effluents in the environment causes the natural ecosystem to become unbalanced [3]. Electrochemical, physicochemical and photochemical treatment including the advanced oxidation process via photo-catalysis or chemical reduction, adsorption and ultra-filtration have been adopted to address this problem [5,6]. Most of these methods are not useful for the treatment of dyes’ polluted wastewater. Methods such as the physicochemical method are inefficient for degradation of dyes due Coatings 2020, 10, 1235; doi:10.3390/coatings10121235 www.mdpi.com/journal/coatings

Methods

Results

Conclusion