Colloidal synthesis of phospholipid-copper nanoclusters as active catalysts for the oxidative degradation of water tracer fluorescent molecule

Abstract

At present the performance of biocompatible metal nanoparticles-driven degradation in solution phase reaction processes are keep on challenging and limited by the lack of common tools to understand. Soy lecithin (SL)–copper oxide nanosuspension (nSLC) was synthesized as an effective homogeneous catalyst for the sonochemical oxidative degradation of rhodamine B (RB) as a model pollutant. SL is known as phosphatidylcholine which is the zwitterionic form of phospholipids that comprise hydrophilic head groups and two tailored hydrophobic groups, assisted in the synthesis of stabilized nanoparticles (NPs); they possibly control the particle growth and stability of the NPs. The nSLC was synthesized by a simple reaction between SL and copper salt, reduction, and purification through simple dialysis. The physicochemical characterizations such as XRD, SEM-EDX, TEM, ATR-FTIR, ZP, DLS and UV–vis spectrophotometry confirmed the formation of nano-lecithin–copper oxides (Cu2O and CuO;<100 nm) with spherical and tailored shapes. The nSLC remained stable for one month and exhibited an excellent catalytic ability for the sonochemical degradation of RB. The stability of nSLC arises from the functional groups of SL that have electron buffering capacity. Various analytical parameters for the degradation of RB were optimized, and complete RB degradation was achieved (>99%) in 5.5 h using H2O2 (100 µL) at pH between 4 and 7. The surface charge of the nSLC and the structure of RB are influenced by pH, which is controlling the degradation pathway. The kinetics of the sonochemical RB degradation fit the first-order kinetic model well with a high r2. The glycerol test confirmed that RB degradation was purely assisted by •OH. The nSLC synthesis and its catalytic application make it a promising environmental catalyst to treat similar organic pollutants and open a new platform for the further development of SL metal-based functional NPs.