Design, synthesis, and characterization of a novel Zn(II)-2-phenyl benzimidazole framework for the removal of organic dyes

Hydrogen bond-mediated self-assembly of Tin (II) oxide wrapped with Chitosan/[BzPy]Cl network: An effective bionanocomposite for textile wastewater remediation

A novel and efficient bionanocomposite was synthesized by incorporating SnO into chitosan (Ch) and a room-temperature ionic liquid (RTIL). The bionanocomposite was synthesized in benzoyl pyridinium chloride [BzPy]Cl to maintain the unique properties of SnO, chitosan, and the ionic liquid. Adsorption and photodegradation processes were applied to evaluate the bionanocomposite for removing azo and anthraquinone dyes and textile wastewater. SnO/[BzPy]Cl and SnO/[BzPy]Cl/Ch samples were prepared and characterized using various techniques, including FT-IR, SEM, XRD, EDAX, XPS, DSC, TGA, nitrogen adsorption/desorption isotherm, and DRS analysis. SEM analysis revealed a hierarchical roughened rose flower-like morphology for the biocomposite. The band gap energies of SnO/[BzPy]Cl and SnO/[BzPy]Cl/chitosan were found to be 3.9 and 3.3 eV, respectively, indicating a reduction in the band gap energy with the introduction of [BzPy]Cl and chitosan. SnO/[BzPy]Cl/Ch showed high removal rates (92-95 %) for Fast Red, Blue 15, Red 120, Blue 94, Yellow 160, and Acid Orange 7 dyes. The adsorption kinetics followed a pseudo-second-order model. In addition, the effect of different photodegradation parameters such as solution pH, dye concentrations, contact time, and amount of photocatalyst, was studied. Given the optimal results obtained in removing azo and anthraquinone dyes, the SnO/[BzPy]Cl/Ch nanocomposite was used as an efficient nanocomposite for removing dyes from textile wastewater. The highest removal efficiency was found to be 95.8 %, obtained under ultraviolet and visible light. Furthermore, BOD and COD reduction analysis showed significant reductions, indicating the excellent performance of the photocatalyst.

MIL-161 Metal-Organic Framework for Efficient Au(III) Recovery from Secondary Resources: Performance, Mechanism, and DFT Calculations

The recovery of precious metals from secondary resources is significant economically and environmentally. However, their separation is still challenging because they often occur in complex metal ion mixtures. The poor selectivity of adsorbents for gold in complicated solutions prevents further application of adsorption technology. In this study, a Zr-based MOF adsorbent, MIL-161, was synthesized using s-tetrazine dicarboxylic acid (H₂STz) as an organic ligand. MIL-161 demonstrated a high adsorption capacity of up to 446.49 mg/g and outstanding selectivity for gold(III) in a simulated electronic waste solution as a result of the presence of sulfur- and nitrogen-containing groups. In addition, the MIL-161 adsorbents were characterized using Fourier transform infrared (FT-IR), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TG), Brunner-Emment-Teller (BET), and X-ray photoelectron spectroscopy (XPS). Additionally, the adsorption kinetics, isotherms, and thermodynamics of the MOF adsorbents were also thoroughly examined. More importantly, the experimental results and DFT calculations indicate that chelation and electrostatic interactions are the main adsorption mechanisms.