Efficient and recyclable AuNPs/aminoclay nanocomposite catalyst for the reduction of organic dyes

Abstract

Industrial dye effluents and organic pollutants pose serious environmental threats for which efficient catalytic adsorbents have been indispensable in treating them. In the present work, the synthesis of gold nanoparticles (AuNPs) dispersed over aminopropyl-functionalized magnesium phyllosilicate (AMP) composites (AuNPs/AMP NC) is reported, involving the organic-inorganic hybrid structure with the strategy of AuNP formation over AMP clay. The AuNPs decorated AMP hybrid nanocomposite was characterised by XRD, FTIR, TGA, UV-Visible, SEM-EDAX, and TEM techniques. The presence of a surface plasmon resonance (SPR) absorption band at 520 nm in UV-Visible spectra revealed the formation of AuNPs over AMP support, which was supported by XRD results. The average particle size of AuNPs with spherical morphology was in the range of 3 nm, respectively. The catalytic performance of the AuNPs/AMP NC was studied through the reduction of malachite green (MG), phenol red (PR), rhodamine B (RhB), rhodamine 6 G (Rh6G), and Congo red (CR) in the presence of NaBH4, respectively. The progress of reductive dye degradation was monitored via UV–Vis spectrophotometry. The kinetic data was analysed and apparent rate constants were determined for the respective dyes. The reduction efficiency of the nanocatalyst over MG, PR, RhB, Rh6G, and CR, in the presence of NaBH4 was determined as > 98%, respectively. Such prolific nanocomposite catalysts could be employed as an alternative to toxic dye and organic component degradation in environmental treatment.