Development of a Nanoparticle Agent for the Batch-scale Disinfection of Water

This project involves the development of a water disinfecting agent for the batch-scale generation of water meeting specifications for coliform removal. The project endeavors to employ low cost, readily available, consumable materials, and common chemical reagents to transform non-potable water from natural sources such as rivers, wells, springs, etc into disinfected water. The desired system will target the chemical engineering technology for treatment of drinking water that has been contaminated by natural disasters (flooding, etc) or generically contaminated by microbial and disease inducing pathogens that may be commonly found in sources of untreated natural water.;The overall process involves the production of silver nanoparticles using naturally available commodity chemical reactions at room temperature. The naturally available commodity investigated cellulose, derived from powdered maple wood, which was processed through mechanical grinding of bulk maple wood with no chemical additives. The use of powdered maple wood as the source of cellulose allowed the process to be cost efficient and naturally based. Size readings of the resultant nanoparticles were measured using a transmission electron microscope (TEM) and dynamic light scattering (DLS). The sizes of the spherical cellulose stabilized AgNP ranged from 40--60nm. Absorbance of the final solution of silver nanoparticles (AgNP) was also measured using ultra violet visible spectroscopy (UV/Vis) resulting in an absorbance intensity value of 3.5 in the characteristic AgNP wavelength of 270--350nm. Further investigation of the generation and stability at an acidic pH of 4.5 indicated an optimal experimental basic pH of 10.7.;Stable suspensions were then used to determine the disinfectant properties of silver nanoparticles on common bacteria found in natural waterways (i.e. E.coli). These minimum inhibitory concentration (MIC) analyses indicated that the cellulose stabilized AgNP were effective at causing cellular death of E.coli at low molar concentrations of 5.5x10-7M AgNP/mL. These MIC analyses were confirmed through the technique of direct plate counting of bacterial colonies. Following the success of the minimum inhibitory concentration determination, coagulation experiments were successfully completed for the effective removal of AgNP from the aqueous system. Scale-up experiments were performed where the contaminated water treatment volume was increased from 1mL to 1000mL. A linear scale up of the treatment dose used for 1mL proved to be effective on the 1000mL scale-up volume, with batch cycle times within 30 minutes.;Following the MIC analysis, the development of a feasibility overview for a portable processor, for production of disinfected water was conducted through the development of a comparison matrix, comparing the cellulose stabilized AgNP to the PUR (TM) water disinfection packets. The matrix revealed the potential use of the cellulose stabilized AgNP as a water disinfecting agent.