Three-Dimensional Coating of Porous Activated Carbons with Silver Nanoparticles and its Scale-up Design for Plant Disease Management in Greenhouses

Abstract

Greenhouse vegetable production is significantly impacted by pathogens that cause diseases to the roots of plants. These diseases are increasingly problematic in hydroponic vegetable production. Standard commercial practices in modern vegetable production facilities reuse the nutrient solution to reduce costs, or use dugout water for greenhouse irrigation in rural areas. This practice of recycling water may introduce or spread pathogens. Once pathogens contaminate water systems, they can spread quickly and cause dramatic losses to yield. Water filters have been used, but do not effectively kill fungi and bacteria. Therefore, better water treatment solutions are urgently needed to manage plant disease, especially for hydroponically grown vegetables. Numerous studies have demonstrated the efficacy of silver ion (Ag+) and silver-based compounds for disinfection of a wide range of harmful microorganisms. In this article, we present a new filter material based on three-dimensional (3D) silver nanoparticle (AgNP)-coated substrates for water treatment. We prepared AgNP-coated active carbon materials and tested their antimicrobial efficacy against phytopathogenic bacterial and fungal spores, such as Pseudomonas sp., and Fusarium sp. We then conducted large-scale tests in a dynamic flow setting and evaluated the effect of the filter on Pythium root rot control of hydroponically grown cucumbers. Results indicated that killing efficiencies of 3D coating were greater than 95% in the laboratory and that cucumber plants had no root infection in AgNP-AC filter treatment. The developed technique is approved to be a very efficient approach and has a great potential to be used in the greenhouse to manage plant root diseases.