Polydopamine mediated in situ synthesis of highly dispersed Gold nanoparticles for continuous flow catalysis and environmental remediation

Abstract

Efficient supported noble metal based catalysts are attracting considerable attention for heterogeneous catalysis and environmental remediation. Herein we report an easy and straightforward method to prepare polydopamine modified cellulose fiber supported gold nanoparticles with size ranging from few nanometers to 20 ± 5 nm as a highly efficient and robust catalyst system. The polydopamine layer on cellulose fibers assists in the immobilization of ions, in situ synthesis, and stabilization of nanoparticles. The polydopamine modification and gold nanoparticles synthesis were thoroughly characterized and tested for catalytic behavior using model p-Nitrophenol (PNP) reduction and dye (Congo red and methylene blue) degradation. Finally, a flow-through reactor was fabricated using the catalytic fibers, and continuous catalytic and dye degradation was assessed under different feed concentrations and flow rates. A complete reduction/degradation was observed up to 7 mL/min flow rate with concentration ranging from 0.06 to 2 mM of nitrophenol and dyes. The flow reactor was capable of continuously running for more than 24 h without any significant loss of activity. Also, just a simple deionized water flush was enough to regain the original activity after 24 h of continuous operations. These results indicate the formation of a superior flow-through reactor compared to many reported systems in the literature.