Effect of calcium silicate nanoparticles applications on salt affected soils environmental conditions

In the present study, various calcium silicate nanoparticles (NPs) were examined to decrease the impact of salinity on the grown plants by adsorbing Na+ and borate (BO_3^(-3) ) from water and soil. The Ca silicate was prepared using a green synthesis technique and subsequently activated by different acids, such as HNO3 and H3PO4, producing Ca silicate-NO3 NPs and Ca silicate-PO4 NPs, respectively. The characterization of the prepared samples was conducted by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS). The removal of Na+ and BO_3^(-3) from solutions was examined by activated calcium silicate NPs, considering different factors such as Na+ and BO_3^(-3) concentrations, adsorption time, solution pH, and temperature. The results highlighted that the maximum removal of Na+ (18.78%) was achieved by using Ca silicate NPs at an equilibrium contact time of 6 h, a concentration of 20 ppm, a pH of 8.1, and a temperature of 298 K. For BO_3^(-3), the maximum removal of (22.47%) was observed at an equilibrium contact time of 6 hours, a concentration of 54.54 ppm, a pH of 6.08, and a temperature of 308.5 K. Freundlich and Langmuir isotherm models were utilized to analyze the experimental data. According to the findings, the Langmuir isotherm model more accurately characterized the experimental data. The adsorption kinetics were studied using the pseudo-first-order and pseudo-second-order models, revealing that the pseudo-second-order model best explained the adsorption kinetics. Furthermore, the study assessed the application of three levels (0, 4, and 8 g pot-1) of Ca silicate NPs, Ca silicate-NO3 NPs, and Ca silicate-PO4 NPs to the dill plants (Anethum graveolens L.). Evaluation parameters include fresh and dry weight, Na, B, Ca, and Si concentrations, and plant tissue trace elements. A significant effect was observed between the concentrations of Na+ in the plant and calcium silicate NPs additives. Regarding boron, adding calcium silicate reduced plants' absorbed amounts.