Assessment of Biomass of Leaves of Water Hyacinth (Eichhornia crassipes) as Reducing Agents for the Synthesis of Nanoparticles of Gold and Silver

Green chemistry methods for nanoparticles synthesis have implemented the valorization of renewable waste that reduces the use of chemicals and sub-products to minimize the environmental impact. Herein, we report a method to synthesize Ag and Au nanoparticles (AgNPs, AuNPs) using one of the world´s worst aquatic weeds, water hyacinth. From a reaction between a solution of AgNO3 or HAuCl4 and controlling the pH, the nanoparticles were synthesized. The optimum pH value to obtained uniform quantum dots was found to be acidic for AgNPs and neutral for AuNPs. The size was highly dependent on pH for AgNPs, a smaller size was for acidic pH, and the larger size was for basic pH, and cubic and hexagonal are the predominant structures, no dependent was observed in AuNPs, and orthorhombic is the most common form. This method was sustainable because water hyacinth is a renewable resource in all world, and their use is not being exploited in any process. The bioreduction process using water hyacinth promotes the metallic nanoparticles formation and applied standard conditions for temperature and pressure. Also, the rate of synthesis is fast.