Adsorptive Desulfurization of Liquid Hydrocarbons Utilizing Granular Cu/Cr-BDC@γ-Al2O3 Bimetal-Organic Frameworks

Preparation of pyrolytic coke/uio-66 composite and its effectiveness for removing mono-ethylene glycol (MEG) from aqueous environments

In the present study, the potential of pyrolytic coke (PC) and PC modified with UiO-66 nanoparticles as adsorbents for removing mono-ethylene glycol (MEG) from aqueous solutions was studied. Different experimental techniques were used to investigate the properties of adsorbents. The modification of the PC surface (6.91 m2/g) with UiO-66 significantly enhanced the specific surface area of the PC/UiO-66 composites, increasing it to 379.31 m2/g. Maximum MEG adsorption using PC (84.21%) and PC/UiO-66 (96.75%) was recorded at pH equal to 5 and 7, MEG quantity of 100 mg/L, temperature of 25 °C, adsorbent dosage of 1 g/L, and treatment time of 120 min, respectively. The Langmuir isotherm adsorption capacities for MEG removal using PC and PC/UiO-66 were determined to be 265 mg/g and 291 mg/g, respectively. The KF and AT values for the MEG adsorption were obtained at 128.1 mg/g (L/mg)1/n and 11.05 L/g, indicating the more pronounced affinity of the PC/UiO-66 towards MEG than the PC sample. The enthalpy, entropy, and Gibbs free energy were determined to be negative; thus, the MEG adsorption was exothermic and spontaneous in the range of 25-50 °C. The results demonstrated that the experimental data adheres to a pseudo-first-order kinetic. The adsorbents were recycled up to five stages, and the results showed that after five cycles, no significant decrease in the adsorption efficiency occurred, making them suitable for repeated utilization in the adsorption process.

Hydrocarbon Extraction with Ionic Liquids

Separation and reaction processes are key components employed in the modern chemical industry, and the former accounts for the majority of the energy consumption therein. In particular, hydrocarbon separation and purification processes, such as aromatics extraction, desulfurization, and denitrification, are challenging in petroleum refinement, an industrial cornerstone that provides raw materials for products used in human activities. The major technical shortcomings in solvent extraction are volatile solvent loss, product entrainment leading to secondary pollution, low separation efficiency, and high regeneration energy consumption due to the use of traditional organic solvents with high boiling points as extraction agents. Ionic liquids (ILs), a class of designable functional solvents or materials, have been widely used in chemical separation processes to replace conventional organic solvents after nearly 30 years of rapid development. Herein, we provide a systematic and comprehensive review of the state-of-the-art progress in ILs in the field of extractive hydrocarbon separation (i.e., aromatics extraction, desulfurization, and denitrification) including (i) molecular thermodynamic models of IL systems that enable rapid large-scale screening of IL candidates and phase equilibrium prediction of extraction processes; (ii) structure-property relationships between anionic and cationic structures of ILs and their separation performance (i.e., selectivity and distribution coefficients); (iii) IL-related extractive separation mechanisms (e.g., the magnitude, strength, and sites of intermolecular interactions depending on the separation system and IL structure); and (iv) process simulation and design of IL-related extraction at the industrial scale based on validated thermodynamic models. In short, this Review provides an easy-to-read exhaustive reference on IL-related extractive separation of hydrocarbon mixtures from the multiscale perspective of molecules, thermodynamics, and processes. It also extends to progress in IL analogs, deep eutectic solvents (DESs) in this research area, and discusses the current challenges faced by ILs in related separation fields as well as future directions and opportunities.

In Situ Design of a Nanostructured Interface between NiMo and CuO Derived from Metal-Organic Framework for Enhanced Hydrogen Evolution in Alkaline Solutions

Hydrogen shows great promise as a carbon-neutral energy carrier that can significantly mitigate global energy challenges, offering a sustainable solution. Exploring catalysts that are highly efficient, cost-effective, and stable for the hydrogen evolution reaction (HER) holds crucial importance. For this, metal-organic framework (MOF) materials have demonstrated extensive applicability as either a heterogeneous catalyst or catalyst precursor. Herein, a nanostructured interface between NiMo/CuO@C derived from Cu-MOF was designed and developed on nickel foam (NF) as a competent HER electrocatalyst in alkaline media. The catalyst exhibited a low overpotential of 85 mV at 10 mA cm-2 that rivals that of Pt/C (83 mV @ 10 mA cm-2). Moreover, the catalyst's durability was measured through chronopotentiometry at a constant current density of -30, -100, and -200 mA cm-2 for 50 h each in 1.0 M KOH. Such enhanced electrocatalytic performance could be ascribed to the presence of highly conductive C and Cu species, the facilitated electron transfer between the components because of the nanostructured interface, and abundant active sites as a result of multiple oxidation states. The existence of an ionized oxygen vacancy (Ov) signal was confirmed in all heat-treated samples through electron paramagnetic resonance (EPR) analysis. This revelation sheds light on the entrapment of electrons in various environments, primarily associated with the underlying defect structures, particularly vacancies. These trapped electrons play a crucial role in augmenting electron conductivity, thereby contributing to an elevated HER performance.

Green valorization of PET waste into functionalized Cu-MOF tailored to catalytic reduction of 4-nitrophenol

Metal-organic frameworks (MOFs) are attractive functional materials due to their high surface area, high porosity, and flexible compositions. However, the high precursor cost and complex synthetic processes hinder their large-scale applications. Herein, a novel green approach has been developed toward the synthesis of Cu-based MOF by a solvent-free mechano-synthesis method and utilizing consumed polyethylene terephthalate (PET)-derived benzenedicarboxylate (BDC) as the linker. The as-prepared CuBDC and aminated CuBDC (CuBDC-NH2) act as green catalysts for the reduction of deleterious 4-nitrophenol (4-NP) into the value-added 4-aminophenol (4-AP). Compared with CuBDC, CuBDC-NH2 shows increased adsorption capability and reduction efficiency. The mechanism and thermodynamic studies suggest that the adsorption of 4-NP on CuBDC-NH2 is an endothermic, spontaneous, favorable, and physical adsorption process. Furthermore, CuBDC-NH2 can expedite the reduction of 4-NP by participating in an adsorptive catalytic process. With the CuBDC-NH2 catalyst, the catalytic normalized kinetic rate of 4-NP was achieved 11.28 mol/min. mg, outperforming state-of-the-art catalysts, and a complete reduction occur in 5 min for a concentrated effluent (200-ppm 4-NP). The plastic waste-derived MOF-mediated catalytic valorization of organic pollutants demonstrated here opens an avenue for the green recycling/utilization of plastic waste, providing meaningful insights into the sustainable management of organic pollutants in wastewater.

High-performance catalytic reduction of 4-nitrophenol to 4-aminophenol using M-BDC (M = Ag, Co, Cr, Mn, and Zr) metal-organic frameworks

The catalytic activity of pure metal nanoparticles is always limited by aggregation during the reaction. Therefore, promising candidates such as metal-organic frameworks possess benefits due to their 3D porous structures, high stability, and high specific surface area. In this study, effective and reusable catalysts based on M-BDC metal-organic frameworks were synthesized utilizing five different coordinating metal ions (M = Ag, Co, Cr, Mn, and Zr) as metal nodes and 1-4-benzene dicarboxylic acid (BDC) as an organic linker and used in catalytic reduction of 4-Nitrophenol (4-NP) to 4-Aminophenol (4-AP) for the first time. The as-prepared catalysts were characterized using SEM, EDX, XRD, and FTIR techniques. Based on catalytic performance, Co-BDC showed the best catalytic efficiency compared to the other M-BDC MOF catalysts with a conversion yield of about 99.25 in 2 min. All of the catalysts could catalyze the complete reduction of 4-NP to 4-AP at different reaction times (2-10); however, Mn-BDC could not finish the catalytic reduction reaction even after 20 min. The two more efficient catalysts including Co-BDC and Cr-BDC demonstrated high stability and reusability (more than 85% catalytic efficiency) even after 5 cycles.

Effective adsorptive removal of sulfamethoxazole (SMX) from aqueous solution by ZIF-8 derived adsorbent ZC-0.5

Efficient removal of antibiotics from the aquatic environment is urgently needed due to their obstinate accumulation and non-biodegradability. In this study, a mesoporous carbon material (ZC-0.5) was successfully synthesized for the adsorption of sulfamethoxazole (SMX), one of the major antibiotics for the treatment of human and animal infections. ZIF-8 as the precursor of ZC-0.5, specifically, using cetyl trimethyl ammonium bromide (CTAB) and sodium laurate (SL) as dual templates and carbonizing at 800 ℃. This novel adsorbent exhibited a high proportion of mesopore (75.64%) and a large specific surface area (1459.73 m²·g^-1). The adsorption experiment examined the reusability of ZC-0.5 and that it could retain superior maximum adsorption capacities (167.45 mg∙L^-1) after five cycles of adsorption and desorption. The adsorption process satisfied the pseudo-second-order kinetic (PSO) and mixed first- and second-order kinetic (MOE). It also satisfied the Freundlich and Sips isotherm models. Moreover, thermodynamic calculation indicated the adsorption process was spontaneous, endothermal, and entropy-increasing. Furthermore, plausible adsorption mechanisms were explained through van der Waals force, electrostatic interaction, hydrophobic force, π-π interaction, and hydrogen bond. This work offers a new efficient adsorbent for antibiotic elimination.