In this study, three acid mine drainage (AMD) sources were investigated as potential sources of iron for the synthesis of iron nanoparticles using green tea extract (an environmentally friendly reductant) or sodium borohydride (a chemical reductant). Electrical conductivity (EC), total dissolved solids (TDS), dissolved oxygen (DO), oxidation-reduction potential (ORP), ion chromatography (IC), and inductively coupled plasma-mass spectroscopy (ICP-MS) techniques were used to characterize the AMD, and the most suitable AMD sample was selected based on availability. Additionally, three tea extracts were characterized using ferric-reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picryl-hydrazine-hydrate (DPPH), and the most suitable environmentally friendly reductant was selected based on the highest FRAP (1152 µmol FeII/g) and DPPH (71%) values. The synthesized iron nanoparticles were characterized and compared using XRD, STEM, Image J, EDS, and FTIR analytical techniques. The study shows that the novel iron nanoparticles produced using the selected green tea (57 nm) and AMD were stable under air due to the surface modification by polyphenols contained in green tea extract, whereas the nanoparticles produced using sodium borohydride (67 nm) were unstable under air and produced a toxic supernatant. Both the AMD-based iron nanoparticles can be used as Fenton-like catalysts for the decoloration of methylene blue solution. While 99% decoloration was achieved by the borohydride-synthesized nanoparticles, 81% decoloration was achieved using green tea-synthesized nanoparticles.

This work focuses on the comparison of H2 evolution in the hydrolysis of boron-containing hydrides (NaBH4, NH3BH3, and (CH2NH2BH3)2) over the Co metal catalyst and the Co3O4-based catalysts. The Co3O4 catalysts were activated in the reaction medium, and a small amount of CuO was added to activate Co3O4 under the action of weaker reducers (NH3BH3, (CH2NH2BH3)2). The high activity of Co3O4 has been previously associated with its reduced states (nanosized CoBn). The performed DFT modeling shows that activating water on the metal-like surface requires overcoming a higher energy barrier compared to hydride activation. The novelty of this study lies in its focus on understanding the impact of the remaining cobalt oxide phase. The XRD, TPR H2, TEM, Raman, and ATR FTIR confirm the formation of oxygen vacancies in the Co3O4 structure in the reaction medium, which increases the amount of adsorbed water. The kinetic isotopic effect measurements in D2O, as well as DFT modeling, reveal differences in water activation between Co and Co3O4-based catalysts. It can be assumed that the oxide phase serves not only as a precursor and support for the reduced nanosized cobalt active component but also as a key catalyst component that improves water activation.

The global production of plywood is constantly increasing as its application in the furniture and interior decoration industry becomes more widespread. An urgent issue is how to decrease the formaldehyde released from plywood, considering its carcinogenic effect on humans and harm to the environment. Reducing the free formaldehyde content of the urea formaldehyde (UF) adhesives used in the preparation process is considered an effective method. Therefore, it is necessary to identify a new type of formaldehyde scavengers. Here, the strongly reducing substance sodium borohydride was used to reduce and degrade the free formaldehyde in UF adhesives, and its effects on the properties of the UF adhesive and plywood were studied. When 0.7% sodium borohydride was added to the UF adhesive with a molar ratio of formaldehyde to urea of 1.4:1, the free formaldehyde content of the UF resin decreased to 0.21%, which is 53% lower than that of the untreated control. Moreover, the formaldehyde released from the plywood was reduced to 0.81 mg/L, ~45% lower than that from the group. The bonding strength of the treated samples could reach ~1.1 MPa, which was only reduced by ~4% compared to that of the control. This study of removing formaldehyde from UF adhesive by reduction could provide a new approach for suppressing formaldehyde release from the final products.

Nano-sized silver has drawn a great deal of attention in the field of health sciences owing to its remarkable therapeutic applications. Interestingly, the method applied to synthesize nanoparticles and the choice of reagents considerably influence their therapeutic potential and toxicities. Current research has explored the toxicity, anti-inflammatory, antinociceptive, and antioxidant responses of the malonic acid-capped silver nanoparticles (MA-AgNPs (C) by using sodium borohydride as a reducing agent at low temperatures by employing both in vitro and in vivo approaches. Furthermore, it has highlighted the synergistic effect of these novel compounds with conventional anti-inflammatory therapeutic agents. Acute and sub-acute toxicity analysis performed following OECD guidelines showed that the studied MA-AgNPs (C) are safer, and prominent toxic signs have not been detected at the highest studied dose of 2,000 mg/kg. Cytotoxicity evaluation through brine shrimp lethality revealed 20% lethality at the highest concentration of 169.8 μg/mL. Significantly, positive anti-inflammatory and analgesic responses alone as well as synergism with the standard were identified through in vitro as well as in vivo methods which were more potent at a lower dose (200 mg/kg). Notably synergistic outcomes were more pronounced than individual ones, indicating their prominent effect as a feasible drug delivery system. IL-6 and TNF-α assessment in excised paw tissue through RTPCR technique further supported their anti-inflammatory potential. DPPH assay revealed eminent in vitro antioxidant activity which was further corroborated by in vivo antioxidant assessment through evaluation of SOD in excised paw tissue.

The nickel-pincer nucleotide (NPN) cofactor discovered in lactate racemase from Lactiplantibacillus plantarum (LarALp) is essential for the activities of racemases/epimerases in the highly diverse LarA superfamily. Prior mechanistic studies have established a proton-coupled hydride-transfer mechanism for LarALp, but direct evidence showing that hydride attacks the C4 atom in the pyridinium ring of NPN has been lacking. Here, we show that sodium borohydride (NaBH4) irreversibly inactivates LarALp accompanied by a rapid color change of the enzyme. The altered ultraviolet-visible spectra during NaBH4 titration supported hydride transfer to C4 of NPN, and the concomitant Ni loss unraveled by mass spectrometry experiments accounted for the irreversible inactivation. High resolution structures of LarALp revealed a substantially weakened C-Ni bond in the metastable sulfite-NPN adduct where the NPN cofactor is in the reduced state. These findings allowed us to propose a mechanism of LarALp inactivation by NaBH4 that provides key insights into the enzyme-catalyzed reaction and sheds light on the reactivity of small molecule NPN mimetics.

The generation of H2 via the catalytic hydrolysis of sodium borohydride (SBH) has promise as a practical and secure approach to produce H2, a secure and environmentally friendly energy source for the foreseeable future. In this study, distinctive trimetallic NiCoPd nanoparticle-supported carbon nanofibers (NiCoPd tri-NPs@CNFs) is synthesized via sol-gel and electrospinning approaches. The fabricated trimetallic catalysts show an excellent catalytic performance for the generation of H2 from the hydrolysis of SBH. Standard physicochemical techniques were used to characterize the as-prepared NiCoPd tri-NPs@CNFs. The results show that NiCoPd tri-NPs@CNFs is formed, with an average particle size of about 21 nm. When compared to NiCo bimetallic NP @CNFS, all NiCoPd tri-NPs@CNFs formulations demonstrated greater catalytic activates for the hydrolysis of SBH. The improved catalytic activity may be due in the majority to the synergistic interaction between the three metals in the trimetallic architecture. Furthermore, the activation energy for the catalytic hydrolysis of SBH by the NiCoPd tri-NPs@CNFs was determined to be 16.30 kJ mol-1. The kinetics studies show that the reaction is of a first order with respect to the catalyst loading amount and a half order with respect to the SBH concentration [SBH].

A facile method for the reduction of carboxylic acid group of Bezafibrate, an approved drug, is described. The selective reduction of carboxylic acid group to corresponding alcohol was carried out by activation of the carboxylic acid moiety via mixed anhydride followed by the addition of stoichiometric amount of NaBH4 and methanol to obtain the first alcohol variant of Bezafibrate. The reaction was completed in 5-10 min in excellent yield and purity. The new alcohol derivative was characterized by spectroscopic methods. This is the first report on this new molecule.

A highly efficient and facile protocol for the selective reduction of carboxylic acid of Fenofibric acid to corresponding alcohol was developed. The selective reduction was carried out by activation of carboxylic acid by mixed anhydride followed by the reaction of sodium borohydride in presence of methanol. This is the first example of chemoselective reduction of carboxylic acid to alcohol in presence of a ketone without any external catalyst or ligand in a single step. The reaction offers wide applicability for the selective carboxylic group reduction methodology. The chemoselective reduction was demonstrated by the reduction of Fenofibric acid, an active metabolite of the drug Fenofibrate, to corresponding alcohol in excellent selectivity, yield, and purity.

As a promising hydrogen storage material, sodium borohydride (NaBH4) exhibits superior stability in alkaline solutions and delivers 10.8 wt.% theoretical hydrogen storage capacity. Nevertheless, its hydrolysis reaction at room temperature must be activated and accelerated by adding an effective catalyst. In this study, we synthesize Co nanoparticles supported on bagasse-derived porous carbon (Co@xPC) for catalytic hydrolytic dehydrogenation of NaBH4. According to the experimental results, Co nanoparticles with uniform particle size and high dispersion are successfully supported on porous carbon to achieve a Co@150PC catalyst. It exhibits particularly high activity of hydrogen generation with the optimal hydrogen production rate of 11086.4 mLH2∙min-1∙gCo-1 and low activation energy (Ea) of 31.25 kJ mol-1. The calculation results based on density functional theory (DFT) indicate that the Co@xPC structure is conducive to the dissociation of [BH4]-, which effectively enhances the hydrolysis efficiency of NaBH4. Moreover, Co@150PC presents an excellent durability, retaining 72.0% of the initial catalyst activity after 15 cycling tests. Moreover, we also explored the degradation mechanism of catalyst performance.

Previous researches suggested that polysaccharides from brown algae had anti-virus activity. We hypothesized that nature polysaccharide from marine plants might have the effect on anti-SARS-CoV-2 activity. By high throughput screening to target 3CLpro enzyme using polysaccharides library, we discover a crude polysaccharide 375 from seaweed Ecklonia kurome blocked 3CLpro enzymatic activity and shows good anti-SARS-CoV-2 infection activity in cell. Further, we show that homogeneous polysaccharide 37502 from the 375 may bind to 3CLpro well and disturb spike protein binding to ACE2 receptor. The structure characterization uncovers that 37502 is alginate. These results imply that the bioactivities of 375 on SARS-CoV-2 may target multiple key molecules implicated in the virus infection and replication. The above results suggest that 375 may be a potential drug candidate against SARS-CoV-2.