Accelerating the Fe(III)/Fe(II) cycle via enhanced electronic effect in NH2-MIL-88B(Fe)/TPB-DMTP-COF composite for boosting photo-Fenton degradation of sulfamerazine.

In the photo-Fenton reactions, fast recombination of photoinduced electrons and holes in Fe-based metal-organic frameworks (Fe-MOFs) slows Fe(III)/Fe(II) cycle, which remains big challenge that significantly retards the overall process. Herein, NH2-MIL-88B(Fe) (NM88) was modified with 3,5-diaminobenzoic acid (DB) and TPB-DMTP-COF (COF-OMe) to in situ construct NM88(DB)0.85/COF-OMe composite that could strongly harvest the visible light for photo-Fenton degradation of sulfamerazine (SMR). With the addition of DB, electron-donating effect of NM88 was strengthened, which then promoted amino groups to react with aldehyde groups (Schiff-base), and thus highly facilitated the interfacial contact between NM88 and COF-OMe. Such modifications increased the degradation rate constants for NM88(DB)0.85/COF-OMe to 15.1 and 17.3 times that of NM88 and COF-OMe respectively with good reusability. Moreover, the catalyst exhibited 32-170 times higher degradation kinetics in comparison to other reported catalysts. Results showed that due to the Schiff-base reaction between NM88(DB) and COF-OMe, electron density on Fe(III) was decreased; and the photogenerated electrons of COF-OMe moved to NM88(DB) to reduce Fe(III), thus resulting in the generation of highly active Fe(II) and ·OH species. Furthermore, the main reactive species were determined to be ·OH and ·O2- by trapping experiments, and a possible mechanism of the degradation system followed Z-scheme charge transfer.

Amino acids imprinted ZIF-8s for the highly efficient and selective adsorption of antioxidant peptides from silkworm pupa protein.

Antioxidant peptides from edible protein sources have attracted great attention due to their high activity, easy adsorption and low toxicity. The purpose of this study was to develop a new MOF material with specific recognition and capture ability to achieve the aim of highly efficient and selective antioxidant peptides from silkworm pupa protein hydrolysate-N (SPPH-N). Firstly, Histidine (His) widely presented in antioxidant peptides was used to in-suit construct the modified ZIF-8 material (ZIF-His) with imprinted defective mesopores, based on "molecular imprinting strategy". Then, it was applied to extract antioxidant peptides from SPPH-N. ZIF-His exhibited high adsorption uptake for antioxidant peptides and especially presented specific adsorption property for peptides contained His, tryptophan, phenylalanine and tyrosine. Three peptides with the highest antioxidant activity (FKVPNMY, AVNMVPFPR and VNMVPFPR) from ZIF-His eluent were identified by Nano-LC-MS/MS. These peptides were synthesized and presented the excellent free radicals scavenging activity and the Ferric reducing power.

Antioxidant Potential, Phytochemicals Composition, and Metal Contents of Datura alba.

This study investigated the phytochemical characteristics and antioxidant activity in leaves, roots, stem, flower, and seed parts of Datura alba (D. alba). The study also assessed the heavy metal (Cr, Mn, Zn, and Cu) accumulation in each part of the plant. Among the phytochemicals, alkaloids were found only in leaves while tannins, flavonoids, and phenols were present in all parts of the plant. For antioxidant activity, free radical scavenging assay for 2,2-diphenyl-1-picrylhydrazyl (DPPH) was performed using ascorbic acid as the standard. Higher activity was shown by stem extract in methanol and leaf extract in n-hexane, ethyl acetate, and chloroform. Furthermore, all the target heavy metals were detected in all plant sections with the highest concentration of Zn in leaves and Cu in stem, root, flower, and seed. Due to stronger antioxidant potential and phytochemical composition, D. alba could prove as valuable prospect in pharmaceutical formulations by taking part in the antioxidant defense system against generation of free radicals.

Hydrodesulfurization of dibenzothiophene using Pd-promoted Co-Mo/Al2O3 and Ni-Mo/Al2O3 catalysts coupled with ionic liquids at ambient operating conditions.

Sulfur compounds in fuel oils are a major source of atmospheric pollution. This study is focused on the hydrodesulfurization (HDS) of dibenzothiophene (DBT) via the coupled application of 0.5 wt% Pd-loaded Co-Mo/Al2O3 and Ni-Mo/Al2O3 catalysts with ionic liquids (ILs) at ambient temperature (120 °C) and pressure (1 MPa H2). The enhanced HDS activity of the solid catalysts coupled with [BMIM]BF4, [(CH3)4N]Cl, [EMIM]AlCl4, and [(n-C8H17)(C4H9)3P]Br was credited to the synergism between hydrogenation by the former and extractive desulfurization and better H2 transport by the latter, which was confirmed by DFT simulation. The Pd-loaded catalysts ranked highest by activity i.e. Pd-Ni-Mo/Al2O3 > Pd-Co-Mo/Al2O3 > Ni-Mo/Al2O3 > Co-Mo/Al2O3. With mild experimental conditions of 1 MPa H2 pressure and 120 °C temperature and an oil : IL ratio of 10 : 3.3, DBT conversion was enhanced from 21% (by blank Ni-Mo/Al2O3) to 70% by Pd-Ni-Mo/Al2O3 coupled with [(n-C8H17)(C4H9)3P]Br. The interaction of polarizable delocalized bonds (in DBT) and van der Waals forces influenced the higher solubility in ILs and hence led to higher DBT conversion. The IL was recycled four times with minimal loss of activity. Fresh and spent catalysts were characterized by FESEM, ICP-MS, EDX, XRD, XPS and BET surface area techniques. GC-MS analysis revealed biphenyl as the major HDS product. This study presents a considerable advance to the classical HDS processes in terms of mild operating conditions, cost-effectiveness, and simplified mechanization, and hence can be envisaged as an alternative approach for fuel oil processing.