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Epidesmine as a silicon source was used to synthesize NaP zeolite by a hydrothermal method. Parameters such as SiO 2 /Al 2 O 3 and H 2 O/Na 2 O molar ratios, reaction temperatures and reaction times were investigated for regulating the purity of the final product. The samples were characterized by X-ray diffraction, infrared spectroscopy and scanning electron microscope. The experimental results evidenced that a high-quality NaP zeolite was obtained at SiO 2 /Al 2 O 3 and H 2 O/Na 2 O molar ratios of 3.7 and 55, respectively, and at a temperature of 95 • C for 6.5 h of ageing. The BET surface area and total pore volume of the powders were 17.1359 m 2 g −1 and 0.006845 cm 3 g −1 , and the pore size was ∼3.2 μm.

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BACKGROUND: Heavy metals present a great challenge due to pollution of the water environment. Conventional adsorption materials may be problematic for sustainable applications due to energy-intensive processing, low adsorption capacity and difficult liquid/solid separation. To address this issue, this study investigated monosaccharide biomass (i.e. glucose) as starting material for hydrothermal synthesis of carbon microspheres (CMS), followed by immobilization of magnetic iron oxide nanoparticles by a chemical co-precipitation method. RESULTS:The results demonstrated that the hydrothermal method could yield high-quality homogeneous carbon microspheres (0.2−0.6 µm in diameter) with abundant oxygen-containing functional groups. The alkali treatment and chemical coprecipitation process produced magnetic Fe 3 O 4 nanoparticles (10-20 nm) uniformly dispersed on the CMS surface. The MCMS exhibited effective adsorption of Cd(II) ions in water, which was consistent with quasi-second-order kinetics and Langmuir isotherms. On reaching adsorption equilibrium, the MCMS could be separated from the liquid phase instantly and completely in the presence of an applied external magnetic field gradient. CONCLUSION: The MCMS synthesized by a hydrothermal and co-precipitation method show great promise as a new sustainable carbon-based adsorbent for potential application in the elimination of heavy metals from water and wastewater.

Understanding the distribution of soil organic carbon and nitrogen (OC(N)) content, cation exchange capacity (CEC), and specific surface area (SSA) in different soil particle sizes is crucial for studying soil fertility and properties. In this study, we investigated the distribution characteristics of the OC(N), CECand SSA in different particles of yellow–brown soil under different methods. The result revealed that as the particle size decreased, the soil OC(N), SSA and CEC content gradually increase. The content of OC and ON different soil particles ranged from 1.50–28.16 g·kg−1 to 0.18–3.78 g·kg−1, respectively, and exhibited significant differences between different particles. We observed good linear relationships between OC and ON in different particle sizes of yellow–brown soil under different utilization methods, with correlation coefficients ranging from 0.86 to 0.98, reaching a very significant level (n = 12, p < 0.01). The ranges of SSA and CEC in different particles of the four soils were 0.30–94.70 m2·g−1 and 0.70–62.91 cmol·kg−1, respectively. Additionally, we found logarithmic relationships between SSA (CEC) and the equivalent diameter for the four soils, with correlation coefficients (r2) higher than 0.91. Furthermore, there was an extremely significant linear relationship between CEC and SSA of the four soils, with correlation coefficients (r2) of 0.92–0.97 (n = 12, p < 0.01). These results highlight the close relationship between soil particle size and soil OC(N), SSA, and CEC. The conclusions drawn from this study provide valuable data support and a theoretical basis for further understanding soil properties.