Color removal from wastewater using a synthetic high-performance antifouling GO-CPTMS@Pd-TKHPP/polyether sulfone nanofiltration membrane

Modified graphene oxide with 5,10,15,20-tetrakis-(4-hexyloxyphenyl)-porphyrin and palladium (II) (signified by GO-CPTMS@Pd-TKHPP) prepared as a novel antifouling polyether sulfone (PES) blended nanofiller membrane. The membrane efficiency has been analyzed such as pure water flux (PWF), hydrophilicity, and antifouling features. By increasing of modified graphene oxide percentage from 0 to 0.1 wt.% in the polymer matrix, the PWF was incremented from 14.35 to 37.33 kg/m2·h at 4 bar. The membrane flux recovery ratio (FRR) has been investigated by applying powdered milk solution; the FRR results indicated that the 0.1 wt.%-modified graphene oxide membrane showed a positive effect on fouling behavior with Rir and FRR value 8.24% and 91.76%, respectively. The nanofiltration membrane performance was assessed applying the Direct Red 16 dye rejection. It was demonstrated that the optimal membranes (0.1 wt.%-modified graphene oxide) had notable dye removal (99.58% rejection). The results are also verified by measuring the scanning electron microscopy (SEM), water contact angle (WCA), and atomic microscopy analysis (AFM).

PdII on Guanidine-Functionalized Fe3O4 Nanoparticles as an Efficient Heterogeneous Catalyst for Suzuki-Miyaura Cross-Coupling and Reduction of Nitroarenes in Aqueous Media

This paper presents guanidine-functionalized Fe3O4 magnetic nanoparticle-supported palladium (II) (Fe3O4@Guanidine-Pd) as an effective catalyst for Suzuki-Miyaura cross-coupling of aryl halides using phenylboronic acids and also for selective reduction of nitroarenes to their corresponding amines. Fe3O4@Guanidine-Pd synthesized is well characterized using FT-IR spectroscopy, XRD, SEM, TEM, EDX, thermal gravimetric analysis, XPS, inductively coupled plasma-optical emission spectroscopy, and vibrating sample magnetometry analysis. The prepared Fe3O4@Guanidine-Pd showed effective catalytic performance in the Suzuki-Miyaura coupling reactions by converting aryl halides to their corresponding biaryl derivatives in an aqueous environment in a shorter reaction time and with a meagerly small amount of catalyst (0.22 mol %). Also, the prepared Fe3O4@Guanidine-Pd effectively reduced nitroarenes to their corresponding amino derivatives in aqueous media at room temperature with a high turnover number and turnover frequency with the least amount of catalyst (0.13 mol %). The most prominent feature of Fe3O4@Guanidine-Pd as a catalyst is the ease of separation of the catalyst from the reaction mixture after the reaction with the help of an external magnet with good recovery yield and also reuse of the recovered catalyst for a few cycles without significant loss in its catalytic activity.

Synthesis and characterization of a supported Pd complex on volcanic pumice laminates textured by cellulose for facilitating Suzuki-Miyaura cross-coupling reactions

Herein, a novel high-performance heterogeneous catalytic system made of volcanic pumice magnetic particles (VPMP), cellulose (CLS) natural polymeric texture, and palladium nanoparticles (Pd NPs) is presented. The introduced VPMP@CLS-Pd composite has been designed based on the principles of green chemistry, and suitably applied in the Suzuki-Miyaura cross-coupling reactions, as an efficient heterogeneous catalytic system. Concisely, the inherent magnetic property of VPMP (30 emu g-1) provides a great possibility for separation of the catalyst particles from the reaction mixture with great ease. In addition, high heterogeneity and high structural stability are obtained by this composition resulting in remarkable recyclability (ten times successive use). As the main catalytic sites, palladium nanoparticles (Pd NPs) are finely distributed onto the VPMP@CLS structure. To catalyze the Suzuki-Miyaura cross-coupling reactions producing biphenyl pharmaceutical derivatives, the present Pd NPs were reduced from chemical state Pd2+ to Pd0. In this regard, a plausible mechanism is submitted in the context as well. As the main result of the performed analytical methods (including FT-IR, EDX, VSM, TGA, FESEM, TEM, BTE, and XPS), it is shown that the spherical-shaped nanoscale Pd particles have been well distributed onto the surfaces of the porous laminate-shaped VPMP. However, the novel designed VPMP@CLS-Pd catalyst is used for facilitating the synthetic reactions of biphenyls, and high reaction yields (∼98%) are obtained in a short reaction time (10 min) by using a small amount of catalytic system (0.01 g), under mild conditions (room temperature).

Design and Fabrication of a Magnetite-based Polymer-supported Hybrid Nanocomposite: A Promising Heterogeneous Catalytic System Utilized in Known Palladium-assisted Coupling Reactions

Objective:

Herein, a novel heterogeneous catalytic system constructed of iron oxide and palladium nanoparticles is presented. Firstly, a convenient synthetic pathway for the preparation of this catalytic system is introduced, then the application of the fabricated nanocomposite in the Pd-catalyzed C─C coupling reactions is monitored. High reaction yields (98%) have been obtained in short reaction time, by using this catalytic system.

Materials and Methods:

Fe3O4/P4VP-Pd catalytic system was fabricated via an in situ method by 4- vinylpyridine (4-VP). In this regard, all the essential structural analyses such as FT-IR, EDX, VSM, and TGA have been performed on the Fe3O4/P4VP-Pd catalytic system to investigate its properties. The spherical morphology of the NPs and their uniform size have also been studied by the SEM method. Further, the reaction progress was controlled by thin-layer chromatography. Finally, NMR analysis was used to identify the synthesized biphenyl pharmaceutical derivatives.

Results:

High efficiency of this catalytic system has been precisely investigated and the optimal conditions were determined. The catalytic process is carried out in 20 min, under mild conditions (room temperature). Then, the purification process is easily performed via magnetic separation of the catalyst NPs. After completion of the synthesis reaction, the NPs were collected, washed, and reused several times.

Conclusion:

Among recently reported heterogeneous catalytic systems, Fe3O4/P4VP-Pd is recommended due to its high catalytic performance, convenience of the preparation process, excellent biocompatibility, economic benefits, and well reusability. Overall, in order to save time in the complex synthetic processes and also prevent using so many chemical reagents and solvents for the purification process, the presented catalytic system could be suitable for scaling up and applying for the industrial applications.

Highly active PdCu/graphene catalyst for an efficient Suzuki cross-coupling reaction

A graphene supported Pd–Cu bimetallic catalyst (Pd–Cu/G) has been successfully fabricated by a simple one-pot solvothermal reaction.

Well-distributed Pt-nanoparticles within confined coordination interspaces of self-sensitized porphyrin metal-organic frameworks: synergistic effect boosting highly efficient photocatalytic hydrogen evolution reaction

Effective conversion of solar energy into chemical energy by visible light represents a potential strategy for sustainable development. Among which, photocatalytic hydrogen evolution reaction (HER) with a relatively small activation energy (1.23 eV, around 1000 nm light irradiation) is especially attractive. In this work, well-distributed platinum nanoparticles (Pt-NPs) with a width of about 3 nm have been successfully immobilized into the confined coordination interspaces of 3.7 nm diameter, which are facilitated by early transition metal Hf(iv)-based clusters of a self-sensitized palladium porphyrin metal-organic framework. Under visible light irradiation, the resultant Pt@Pd-PCN-222(Hf) (which is also denoted as Pt@Pd-PMOF-2(Hf)) displays superb photocatalytic activity, achieving an unprecedented maximum H2 evolution rate of 22 674 μmol g-1 h-1 with a turn-over number (TON) of 4131.2 in 32 h and the highest turn-over frequency (TOF) of 482.5 h-1 based on Pt-NPs. This photocatalyst can be recycled and reused for three successive runs without significant loss of catalytic activity. This effective strategy takes advantage of the synergetic effect between Pd-porphyrin photosensitizers and Pt-NP co-catalysts confined within nanoscale coordination interspaces incorporating hydrophilic Hf(iv)-oxo clusters.

Palladium decorated on a new dendritic complex with nitrogen ligation grafted to graphene oxide: fabrication, characterization, and catalytic application

Immobilized Pd nanoparticles on a new ligand, namely, tris(pentaethylene-pentamine)triazine supported on graphene oxide (Pdnp-TPEPTA(L)-GO) was introduced as a novel and robust heterogeneous catalyst for use in C-C bond formation reaction. The Pdnp-TPEPTA(L)-GO catalyst was synthesized by complexation of Pd with TPEPTA as a ligand with high N-ligation sites that were supported on graphene oxide through 3-chloropropyltrimethoxysilane. The prepared catalyst was characterized using some microscopic and spectroscopic techniques. The TPEPTA(L)-GO substrate is a 2D heterogeneous catalyst with a high specific surface area and a large amount of N-ligation sites. The Pdnp-TPEPTA(L)-GO catalyst used in the C-C bond formation reaction between aryl or heteroaryl and phenylboronic acid derivatives was applied towards the synthesis of biaryl units in high isolated yields. Notably, a series of competing experiments were performed to establish the selectivity trends of the presented method. Also, this catalyst system was reusable at least six times without a significant decrease in its catalytic activity.