Multifunctional Iron–Humic Acid Fertilizer from Ball Milling Double-Shelled Fe–N-doped Hollow Mesoporous Carbon Microspheres with Lignite

Abstract

Iron (Fe) chelated by water-soluble humic substances can effectively overcome plant micronutrient deficiencies. However, the traditional synthesis methods are often complex, expensive, and thus not applicable to large-scale industrial productions. In this work, an ecofriendly and multifunctional Fe−humic acid (HA) complex was successfully prepared through simply ball milling lignite with doubleshelled Fe−N hollow mesoporous carbon microspheres (DS−Fe−N− HC). The novel DS−Fe−N−HC was synthesized using a simple strategy and was first applied in activating HA from lignite by solidphase ball milling to attain the water-soluble HA−iron fertilizer (WHIF). The physicochemical properties of the DS−Fe−N−HC nanocomposites and WHIF were systematically characterized by a series of techniques. A traditional Fe−HA complex is mainly obtained by mixing HA and iron ions, which has poor water solubility because HA is not activated. In comparison to samples prepared with other methods, WHIF contained more stable water-soluble HA. Furthermore, the as-obtained WHIF had higher amounts of proteins and amino sugar tannin as evidenced in FT-ICR MS analysis. Moreover, WHIF contributed to higher activities in chlorophyll content, height, steam diameter, and biomass of peanuts than other samples. The results demonstrate that WHIF is effective in reducing symptoms of iron deficiency in peanuts, which can be attributed to its iron-based compounds and water-soluble HA. The findings of this study provide a promising, cost-effective, and environmentally friendly solution to mitigate iron deficiency and promote the growth of peanuts for large-scale agriculture production.

Synthesis of Urea-Formaldehyde Fertilizers and Analysis of Factors Affecting These Processes

“…The surface morphologies of samples CN1-3 (Figure 9) and CN5-3 (Figure 10) were recorded by SEM. The images suggest that CN1-3 had a closer arrangement of surface substances, fewer pores, and a smaller specific surface area than CN5-3 [28][29][30]. At higher magnification, CN1-3 appeared as clumps of macromolecular material with dense and smooth surfaces, few pores, large particle size, and a small specific surface area.…”

Ammonium Sulfite Slurry from Ammonia-Based Desulfurization Activates Water-Soluble Humic Substances from Lignite: Performance, Application, and Mechanism

“…9 Therefore, the activation method of lignite needs to be further optimized. Previous research has developed materials such as Pd/CeO 2 , 8 3D-MoS 2 −HN, 10 DS−Fe−N-HC, 11 and TiO 2 −WO 3 12 as catalysts to activate lignite to obtain WHSs. In general, the above catalytic process is positive for the activation of lignite, but the synthesis conditions of the catalyst are harsh and the raw material cost is high.…”