Icpe 9000 spectrometer

Soil samples were taken from each plot at a depth of approximately 0–30 cm using a polyvinyl chloride cylinder or soil sampler (DIK-1601; Daiki Rika Kogyo) on July 7 and November 17, 2016, which corresponded to the start and end of the soybean cultivation period, respectively. Samples were air-dried and passed through a 2-mm sieve, and the fine earth obtained was subjected to soil chemical analysis. The oven-dried weight of the fine earth was measured to obtain moisture correction factors that were used to convert nutrient contents of air-dried soil to a dry weight basis.
Total carbon and total nitrogen contents were determined using the dry combustion method with an elemental analyzer (Sumigraph NC-220F; Sumika Chemical Analysis Service, Osaka, Japan). Exchangeable bases (K⁺) extracted in 1 M ammonium acetate (pH 7) were measured with an inductively coupled plasma atomic emission spectroscopy (ICPE-9000 spectrometer, Shimadzu Corporation, Kyoto, Japan)⁶² . Available phosphorus was determined using the Bray-II method⁶³ with a UV-1800 spectrophotometer (Shimadzu Corporation).

X-ray diffraction (XRD) measurements were performed on a Bruker Powder D8 Advance diffractometer (Billerica, MA, USA) at 40 kV and 40 mA using CuKa radiation (λ = 1.5418 Angstrom). DRUV/Vis spectra were recorded on a Shimadzu UV-2450 spectrophotometer (Kyoto, Japan) at 298 K using BaSO₄ as a reference. FTIR spectra were recorded as KBr pellets on a Shimadzu IRPrestige-21 spectrometer (Kyoto, Japan). FTIR spectrum of pyridine adsorbed on TS-1 zeolites was tested at 298 K in a sealed reaction cell with KBr windows. A self-supporting disc (20 mg with 2.0 cm diameter) was prepared and evacuated at 723 K for 1 h. Subsequently, pyridine vapor was introduced and kept for 30 min. Excess pyridine was removed by vacuuming at 423 K for 30 min. The FTIR spectrum was collected in absorbance mode after the disc cooled to room temperature. Nitrogen adsorption–desorption isotherms were measured on a TriStar II 3020 sorption analyzer (Norcross, GA, USA) at 77 K. Elemental analyses (Si, Ti, and Na) were performed on an inductively coupled plasma optical emission spectrometer (Shimadzu ICPE-9000 spectrometer, Kyoto, Japan). Scanning electron microscopy (SEM) images were obtained on a JEOL JSM-7600F microscope (Tokyo, Japan) operated at 20 kV. Particle sizes were measured on a Malvern Zetasizer Nano ZS90 analyzer (Malvern, UK).