Soil pollution caused by potentially toxic transition metals has become a worldwide environmental issue. Geogenic processes and anthropogenic activities are two important sources of soil pollution. Soils may inherit toxic transition metals from parent materials; however, soil pollution mostly results from industrial and agricultural activities. Contamination by transition metals can be indicated by the changes in chemical, biochemical, and microbial properties of soils and plant responses. The target of this research is removing transition metals of chromium (Cr), manganese (Mn), iron (Fe), zinc (Zn), tungsten (W), cadmium (Cd) from soil due to nanomaterial-based boron nitride nanocage (B5N10-nc). The electromagnetic and thermodynamic attributes of toxic transition metals trapped in B5N10-nc was depicted by materials modeling. The encapsulation of these elements occurs via chemisorption. It has been studied the behavior of trapping of Cr, Mn, Fe, Zn, W, Cd by B5N10-nc for sensing the soil metal cations. B5N10-nc was designed in the existence of transition metals (Cr, Mn, Fe, Zn, W, Cd). Case characterization was performed by DFT method. The nature of covalent features for these complexes has represented the analogous energy amount and vision of the partial density of states between the p states of boron and nitrogen in B5N10-nc with d states of transition metals in X B5N10-nc complexes (X= Cr, Mn, Fe, Zn, W, Cd). Furthermore, the nuclear magnetic resonance (NMR) analysis indicated the notable peaks surrounding Cr, Mn, Fe, Zn, W, Cd through the trapping in the B5N10-nc during atom detection and removal from soil; however, it can be seen some fluctuations in the chemical shielding treatment of isotropic and anisotropy tensors. Based on the results in this research, the selectivity of toxic metal, metalloid and nonmetal elements adsorption by B5N10-nc (atom sensor) have been indicated as: Cd > Zn > Fe > Cr > Mn approximate to W. In this article, it is proposed that toxic metal, metalloid and nonmetal elements-adsorbed might be applied to design and expand the optoelectronic specifications of B5N10-nc for generating photoelectric instruments toward soil purification.

Construction resting on soil and rocks containing montmorillonite (MMT) are prone to damage induced by swelling, which involves a significant release of energy. It is often desirable to enhance these soils to mitigate swelling potential, regulate volume changes, and manage energy release. Experimental findings suggest that increasing temperature is one method to improve these soils, with water content, initial volume, and boundary conditions also influencing the swelling mechanism. This study utilizes ab initio molecular dynamics calculations to explore changes in volume and energy within MMT unit cells at the nanoscale due to temperature variations. The response of unit cells of MMT with varying dimensions and quantities of water molecules to temperature is assessed under constrained and unconstrained conditions. Results indicate that the volume changes and energy release of unit cells in response to temperature are contingent upon the presence of water molecules. In unit cells containing water molecules, both energy and volume decrease with rising temperature, whereas in unit cells devoid of water molecules, energy decreases while volume increases as temperature rises. Given the inherent association of soils with water in natural settings, it can be deduced that increasing temperature presents a viable method for enhancing naturally occurring MMT-dominated soils. Density functional theory calculations demonstrate that alterations in the volume and energy of MMT stem from shifts in interactions among the minerals, cations, and water molecules, as well as intrinsic structural defects like isomorphic substitution and peroxy links within the unit cells. These modifications induce variations in charge carriers and electrical properties, consequently influencing volume and energy changes within MMT unit cells. Additionally, it was observed that the failure of peroxy links can significantly impact the optimal temperature selection for the thermal enhancement of MMT.

Over -application of nitrogen fertilizer induces soil acidification, which activates heavy metals availability and poses significant challenge to crop production and food safety. In this study, we prepared a clay-based material by ball-milling bentonite with NH4Cl (NH4Cl@bentonite) and assessed its synergistic performance in enhancing nitrogen fertilizer utilization efficiency, immobilizing heavy metals, and improving crop yield and safety. The results showed that the optimal performance of NH4Cl@bentonite was achieved by milling bentonite with NH4Cl at a 4:1 mass ratio for 9 h. NH4Cl@bentonite significantly improved soil water holding and retention capacity by 1.6 and 4.3 times, respectively. In comparison to NH4Cl alone, NH4Cl@bentonite led to a 22.3% increase in N -use efficiency and a 1.5 times enhancement in crop yield. The Pb and Cd content in water spinach shoots decreased by 55.3% and 57.5%, respectively, attributed to the transformation of heavy metals into lower bioavailability states by NH4Cl@bentonite. Experiments and Density Functional Theory (DFT) calculations indicated that NH4Cl@bentonite could immobilize Pb and Cd through processes such as cation exchange, surface adsorption, complexation, and enhancement of soil pH. This work proposes a simple and efficient method for improving cropland fertilizer utilization while ensuring healthy and sustainable development. Environmental implication: Soil acidification, caused using chemical fertilizers, especially nitrogen -based ones, threatens crop production and food safety by damaging soil structure, speeding up nutrient loss, and increasing the solubility of heavy metals. To tackle this problem, we made a clay material by mixing bentonite with NH4Cl (NH4Cl@bentonite) in a ball mill. NH4Cl@bentonite increased N -use efficiency by 22.3%, boosted crop yield by 1.5 times, and reduced the Pb and Cd levels in water spinach shoots by 55.3% and 57.5%, respectively. This work suggests a simple and effective way to enhance fertilizer use in croplands while ensuring healthy and sustainable development.

The nanoscale zerovalent iron (nZVI) was successfully modified with sulfidation and loaded by kaolin (K@SnZVI) for enhanced persulfate (PS) activation. K@S-nZVI was characterized by SEM-EDS, TEM, XPS, BET and XRD. The better degradation performance of BDE209 was in the following order: K@S-nZVI/PS> S-nZVI/PS> nZVI/PS> > systems without PS activation. The maximum removal of BDE209 was 88.32% under PS concentration of 0.2 mol/L, soil-water ratio of 1:2.5 and the molar ratio of K@S-nZVI/PS of 2:1. The reactive oxygen species in the K@S-nZVI/PS system were identified by EPR and quenching experiments as SO4- & sdot;,& sdot;OH,& sdot;O(2)(- )and the nonracial of 1 O2. SO4-& sdot; and & sdot;O-2(-) dominated the degradation of BDE209 and & sdot;OH and 1 O2 were involved. According to gas chromatography-mass spectrometer (GC-MS) and density functional theory (DFT) calculations, BDE209 could be degraded to BDE7 by gradual debromination and further degraded into Br- and short-chain acids by ring opening reaction of benzene ring. The coexistence of SO42-, Cl- , CO32-, NO3- and HA reduced the degradation of BDE209. The soil pH did not change significantly during the remediation process. At the beginning of remediation process, soil catalase activities were enhanced while phosphatase and urease activities were weakened but they all recovered finally, exhibiting less damage to microbial cells. The K@S-nZVI/PS system is expected to be practically applied to the remediation of BDE209 contaminated soil.