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[Display omitted] In the adsorption process of functionalized layered double hydroxide (LDH) to target pollutants it, is essential to investigate the role of functional groups. In this work, 2‑mercaptoethane sulfonic acid (MS) was used as an intercalation modifier to prepare functionalized NiFe-LDH by solvothermal method. The interfacial interaction between the functional groups and the NiFe-LDH surface was studied via molecular dynamics simulation. During the intercalation process, the more negatively charged sulfonic acid group tends to self-assemble electrostatically with the LDH laminate, while the sulfhydryl group is involved in complexing heavy metal ions. The adsorption experiments showed that the adsorption performance of the adsorbent for the three ions of Cd2+, Mn2+, and Co2+ at 298.15 K was 266.16 mg/g, 175.60 mg/g, and 106.56 mg/g, respectively, which were 10 times, 8.7 times, and 4.9 times higher than that of unmodified NiFe-LDH. Meanwhile, Multiwfn wavefunction analysis combined Visual Molecular Dynamics (VMD) was applied to analyze and visualize the reaction active sites & the interactions between MS and NiFe-LDH, and the complexation of the functional group of MS with metal ions, to insight the role of the functional groups in MS molecule, and to reveal the cause that the adsorption capacity of modified NiFe-LDH for heavy metals greatly improves from the view of atoms. [ABSTRACT FROM AUTHOR]

The corresponding adsorption mechanism of the adsorbent in the process of adsorbing phosphate. As shown, three adsorption mechanisms of the adsorbent in the process of adsorbing phosphate: 1: The combination of PO 4 3− and La3+ produces LaPO 4 with smaller Ksp. 2: H 2 PO 4 − and HPO 4 2− enters the interlayer through a substitution reaction with OH− between the LDH layers to realize the adsorption of phosphate. 3: The electrostatic mutual attraction between quercetin and phosphate realizes the adsorption of phosphate. [Display omitted] Severe water eutrophication due to large releases of phosphorus has become a worldwide environmental problem. Adsorption active sites is less of traditional adsorbents in the phosphorus removal process resulting in low removal efficiency, so the new high-efficiency phosphorus removal adsorbents become an effective way to solve the problem. In this work, quercetin modified MnFe layered double hydrotalcite three-dimensional composites structures encapsulated by lanthanum (La(III)) nanoparticles (QLa@MnFe-LDH) were successfully prepared by a classical hydrothermal method. The results of the adsorption experiments show that La(III) nanosphere-encapsulated MnFe-LDH provides a more adequate binding site for phosphate adsorption. The adsorption performance of QLa@MnFe-LDH for phosphate was outstanding, the maximum adsorption capacity was 346.5 mg/g at 298.15 K, which was 300 % higher than that of MnFe-LDH. Moreover, QLa@MnFe-LDH retained its high adsorption capacity (>315.5 mg/g) over a wide range of pH (4.0 ∼ 7.0). The active sites of the reactions were predicted by Multiwfn and Visual Molecular Dynamics (VMD), and novel visualization studies of weak interactions were applied to theoretical studies. The modified MnFe-LDH encapsulated by La nanospheres has a strong adsorption capacity for phosphate adsorption. Therefore, the modified QLa@MnFe-LDH was expected to become an effective adsorption material for phosphorus removal. [ABSTRACT FROM AUTHOR]

Developing a 3D material to support α-Fe 2 O 3 nanorods to improve their adsorption performance for Congo Red (CR) is a major challenge. Herein, a novel 3D composite adsorbent was designed, where 2D material Ti 3 C 2 MX and CoFe-LDH stacked on top of each other as the support material of α-Fe 2 O 3 nanorods (α-Fe 2 O 3 @LDH@MX). The specific surface area of the α-Fe 2 O 3 @LDH@MX was increased by 2 times (101.28 m2/g) than original CoFe-LDH@MX, thus more favorable for capturing CR (698.25 mg/g). The results of kinetic studies demonstrate that the effective 3D composite structure enables unhindered movement of CR within the α-Fe 2 O 3 @LDH@MX. The Langmuir model can accurately describe the adsorption process of CR on the α-Fe 2 O 3 @LDH@MX, which means that the process belongs to monomolecular layer chemisorption. Molecular dynamics simulations revealed that the α-Fe 2 O 3 interface primarily interacts with oxygen within the -SO 3 group, achieving an adsorption energy up to E in teraction = −20,375.89 kcal/mol. The results of XPS analysis further revealed that interaction between Fe and O achieved the removal of CR. In this paper, the enhancement of α-Fe 2 O 3 adsorption performance has been successfully achieved through innovative structural design. This significantly advances its potential applications and offers new insights for future material design. [Display omitted] • 3D support improves the exposure of α-Fe 2 O 3 nanorod active sites and promotes rapid response to Congo red. • α-Fe 2 O 3 @LDH@MX has outstanding adsorption capacity for Congo red and excellent anti-interference ability. • Quantum chemistry and molecular dynamics simulations were used to provide in-depth insights into the adsorption mechanism. [ABSTRACT FROM AUTHOR]

Highly efficient multifunctional adsorbent successfully realizes the removal of Cr ions from wastewater. The adsorbent is easily separated from the water to avoid secondary pollution. [Display omitted] • A novel 3D multifunctional composite magnetic adsorbent material has been successfully synthesized and applied for the removal of Cr(VI) from solution. • The composite adsorbent enables efficient capture and reduction of Cr(VI) under full light exclusion conditions. • The exceptional recyclability mitigates the issue of secondary contamination from the adsorbent. Designing a magnetic adsorbent material that is both reducible and has strong adsorption properties is significant in reducing Cr(VI) ion pollution. Herein, a 3D multifunctional composite adsorbent for Cr(VI) ions was obtained by using Fe 3 O 4 surface-arrayed magnesium iron layered double hydroxides (Mg/Fe-LDH) micro sheets as a substrate with in situ growth of Cu 2 O nanoparticles (Cu 2 O NPs) on their surfaces. Under dark conditions, adsorption capacity of the Cu 2 O@LDH@Fe 3 O 4 for Cr(VI) was up to 218.82 mg·g−1, surpassing that of Cu 2 O, Mg/Fe-LDH@Fe 3 O 4 , and Mg/Fe-LDH by factors of 1.39, 4.41, and 8.32 respectively. Surprisingly, the removal of Cr(VI) was as high as 76.16 % by the Cu 2 O@LDH@Fe 3 O 4 (C initial = 200 mg/L, pH = 3). Kinetic, isotherm, and thermodynamic results reveal that the removal of Cr(VI) by the Cu 2 O@LDH@Fe 3 O 4 is consistent with the pseudo-second-order kinetic model of spontaneous monomolecular layer chemisorption. Density functional theory (DFT) calculations show that HCrO 4 - has a lower energy band gap and is more easily reduced by Cu 2 O. Therefore, the reason for the adsorbent having more removal effect under acidic conditions was revealed. The XPS and FT-IR experimental mechanism analysis results indicated that Cr(VI) is immobilized on the Cu 2 O@LDH@Fe 3 O 4 surface through electrostatic interactions, followed by reduction to Cr(III) by Cu 2 O NPs, which is subsequently adsorbed on the surface of the Cu 2 O@LDH@Fe 3 O 4. This novel adsorbent structure and unique Cr(VI) removal mechanism provide new ideas for the design of future adsorbents. [ABSTRACT FROM AUTHOR]

[Display omitted] • High dispersion and stable attachment of LDH on nitrogen and sulfur doped porous carbon (NSPC). • The synergistic effect of LDH and NSPC enhances the adsorption of heavy metal ions. • The adsorption mechanism was attributed to surface complexation. Layered double hydroxides (LDHs) composites (NSPC@LDH) were successfully prepared on nitrogen and sulfur-doped porous carbon (NSPC) by a simple co-precipitation method. The synergistic effect between the modified porous carbon and LDH enhanced its adsorption performance. Compared with pure LDH, the composite had a larger specific surface area (188.78 m2/g) and pore structure with a smaller crystallite size (4.56 nm). The porous carbon carrier effectively mitigated the aggregation effect of LDH. The maximum adsorption capacities of NSPC@LDH for Zn2+ (100 ppm) and Cu2+ (100 ppm) were 125.7 mg/g and 137.5 mg/g, respectively, which were 2.85 and 2.39 times the original LDH. The XRD and XPS studies of the adsorbent after adsorption revealed that surface complexation and physical adsorption played a dominant role in the removal of Zn2+ and Cu2+, and the introduction of N, S heteroatoms provided more active centers for heavy metal ions. Moreover, after five desorption cycles, NSPC@LDH still exhibited high removal efficiency. The results indicated that the synthesized NSPC@LDH composites have great potential for removing Zn2+ and Cu2+ from aqueous solutions. [ABSTRACT FROM AUTHOR]