Earth-Abundant Catalyst for Modification of Wheat Straw to Enhance Ammonia Mitigation from Fertilised Alkaline Soil

Abstract

In this study, inexpensive earth-abundant catalyst of Co/TiO2 is coupled with a low-temperature modification approach to enhance NH3 adsorption capacity on wheat straw (WS). The highest NH3 uptake achieved is 111.9 mg/g, with 80.8% retention even after 3 hours of desorption. Mechanistic investigation indicates that the enhanced adsorption capacity stems from Co/TiO2, which facilitates generation of reactive oxygen species, leading improved ultra-micropore structure that enhances the interaction between NH3 and oxygen-containing functional groups through a trapping effect. The robust stability of adsorbed NH3 is attributed to the formation of amides or amines. Incorporation of only 1 wt.% WS-Co to urea-fertilised alkaline soil reduced NH3 volatilization by 83.1%. The significant effect is primarily attributed to the excellent adsorption capacity of WS-Co, rather than alterations in the relative abundance of the microbial community. These findings present a novel approach for development of effective fertilizer additive to mitigate NH3 volatilization from alkaline soil.

Keywords: Nitrogen fertiliser, cobalt, titanium dioxide, catalysis, Adsorption