Optimized procedure for the determination of P species in soil by liquid-state 31P-NMR spectroscopy

Abstract

Background: Liquid-state

Design and Kinetic Study of Sustainable Potential Slow-Release Fertilizer Obtained by Mechanochemical Activation of Clay Minerals and Potassium Monohydrogen Phosphate

“…In the 31 P MAS NMR spectra, similar modifications as previously described for MMT based SSRF were observed, with the replacement of the well-defined signals by a broad chemical environment, shifted to the orthophosphate region (δ = 2.5 ppm) (Figure Cc), probably involving Mg–O–P bonds. Obviously, the solid state NMR results were in good agreement with the results obtained by PXRD and further evidenced the formation of amorphous materials due to mechanochemical activation by milling. − Thermogravimetric analyses (Figure ) were performed for all precursors and milled samples in order to investigate the effect of mechanochemical treatment on composition.…”

“…A similar behavior was reported for the milling of raw minerals. 15 In the 31 P MAS NMR spectra, similar modifications as previously described for MMT based SSRF were observed, with the replacement of the well-defined signals by a broad chemical environment, shifted to the orthophosphate region (δ = 2.5 ppm) (Figure 3Cc), 22 probably involving Mg−O−P bonds. Obviously, the solid state NMR results were in good agreement with the results obtained by PXRD and further evidenced the formation of amorphous materials due to mechanochemical activation by milling.…”

“…Interestingly, at longer times (Figure 8Ce), the signals between δ = 10 ppm and δ = −10 ppm increased in relative intensity, highlighting the orthophosphatelike environment modification toward monodentate, bidentate, and pyrophosphate species. 22 The 29 Si signal was unmodified compared to milled SSRF.…”

Potential Sustainable Slow-Release Fertilizers Obtained by Mechanochemical Activation of MgAl and MgFe Layered Double Hydroxides and K2HPO4

“…The 31 P NMR spectra of anhydrous K 2 HPO 4 ( Figure 5 c) was characterized by four sharp signals located at δ = 6.0; 2.6; −0.7 and −5.2 ppm [ 34 ]. After the mechanochemical reaction between calcined MgAl and K 2 HPO 4 , the 31 P NMR signals ( Figure 5 d) broadened over a large spectral width (δ = −10 to +15 ppm) due to both strong amorphization and a change in the P environment.…”

The distribution of phosphorus from recycled fertilizers to different soil fractions determines the phosphorus availability in soil

“…Po analysis was also performed by NaOH-EDTA extraction followed by 31 P-NMR analysis (Xu et al, 2012;Li et al, 2015). For the 31 P-NMR analysis, soil samples at the end of 70-day incubation were ground into powder and sieved through a 100-μm mesh.…”