Efficient reduction of dyes to leuco form over silver nanoparticles on functionalised SBA-15 and aminoclay

ABSTRACT

In this work, a simple chemical method for synthesis of Ag nanoparticles (NPs) incorporated on amine-functionalised mesoporous silica SBA-15 support (Ag/NH₂-SBA-15) is reported for various dye degradation as the first time. The synthesised sample was characterised by powder XRD, BET surface area and pore size analyser, ICP-OES, XPS HRTEM, and HRSEM techniques. About 5 nm-sized Ag nanoparticles are dispersed over the support. The Ag/NH₂-SBA-15 catalytic efficiency was investigated on various dyes degradation such as Malachite green (MG), Phenol red (PR), Bromophenol blue (BPB), Rose Bengal (RB), Methylene Blue (MB), Rhodamine derivatives (Rh 6 G, Rh B), Congo red (CR) and 4-Nitrophenol (4-NP) in the presence of NaBH₄. About 90% degradation efficiency resulted in 6 min of reaction time in the presence of a catalyst. Besides, the Ag/NH₂-SBA-15 catalyst activity has been compared with homogeneous Ag/aminoclay and shown higher catalytic activity. All the reactions were monitored by UV-Visible spectrometer. The reaction kinetics of Ag nanoparticle catalysed reduction illustrates pseudo-first-order kinetics with the rate constant for the reduction is in the order Ag/NH₂-SBA-15 (3.34 × 10⁻¹ s⁻¹) and Ag/aminoclay (1.80 × 10⁻² s⁻¹).

KEYWORDS:

• Amine-functionalisation
• silver nanoparticles
• SBA-15
• NaBH₄
• reduction
• aminoclay

Acknowledgments

The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through the research group program under grant number R.G.P.1/172/41. The author VVS greatly acknowledges the DST-SERB, New Delhi for providing National Post-Doctoral Fellowship (NPDF/2016/002344) to carry out the research work.

Compliance with ethical standards Conflict of Interest

The authors declare that they have no conflict of interest.

Disclosure statement

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

Additional information

Funding

This work was supported by the Deanship of Scientific Research at King Khalid University .