The effect of carbonized zeolitic imidazolate framework-67 (ZIF-67) support on the reactivity and selectivity of bimetal-catalytic aqueous NO3- reduction.

A metallic catalyst, Cobalt N-doped Carbon (Co@NC), was obtained from Zeolitic-Imidazolate Framework-67 (ZIF-67) for efficient aqueous nitrate (NO3-) removal. This advanced catalyst indicated remarkable efficiency by generating valuable ammonium (NH3/NH4+) via an environmentally friendly production technique during the nitrate treatment. Among various metals (Cu, Pt, Pd, Sn, Ru, and Ni), 3.6%Pt-Co@NC exhibited an exceptional nitrate removal, demonstrating a complete removal of 60 mg/L NO3--N (265 mg/L NO3-) in 30 min with the fastest removal kinetics (11.4 × 10-2 min-1) and 99.5% NH4+ selectivity. The synergistic effect of bimetallic Pt-Co@NC led to 100% aqueous NO3- removal, outperforming the reactivity by bare ZIF-67 (3.67%). The XPS analysis illustrated Co's promotor role for NO3- reduction to less oxidized nitrogen species and Pt's hydrogenation role for further reduction to NH4+. The durability test revealed a slight decrease in NO3- removal, which started from the third cycle (95%) and slowly proceeded to the sixth cycle (80.2%), while NH4+ selectivity exceeded 82% with no notable Co or Pt leaching throughout seven consecutive cycles. This research shed light on the significance of the impregnated Pt metal and Co exposed on the Co@NC surface for the catalytic nitrate treatment, leading to a sustainable approach for the effective removal of nitrate and economical NH4+ production.

Investigating potential anti-proliferative activity of different statins against five cancer cell lines.

Statins have been reported to have potential anti-proliferative effects through an unknown mechanism. This study aims to investigate the anti-proliferative activities of five statins, including simvastatin, rosuvastatin, fluvastatin, atorvastatin, and pravastatin, against five different cancer cell lines; cervical epithelial carcinoma DoTc2 4510, malignant melanoma A-375, muscle Ewing's sarcoma A-673, hepatocellular carcinoma HUH-7, as well as breast cancer cells MCF-7. At 100 µM, simvastatin and atorvastatin significantly inhibited 70% of cellular proliferation. At the same concentration, rosuvastatin and fluvastatin showed about 50% of inhibition only in A-375 and A-673 cancer cells in a time- and dose-dependent manner. Of all the statin drugs used, pravastatin had the least inhibitory effect on all the cancer cell lines. Western Blot analysis showed a decrease in mTOR level, and the expression of p53 tumour suppression and BCL-2 proteins was relatively elevated compared to the untreated cells. Simvastatin and atorvastatin may inhibit cellular proliferation via BCL-2/p53, Bax/Bak, and PI3K/Akt/mTOR signalling pathways. This is the first research to evaluate the anti-cancer effects of simvastatin, rosuvastatin, fluvastatin, atorvastatin, and pravastatin against five different cell lines from distinct origins and provided a relevant comparison of their efficacies for their anti-proliferative activity.

The Use of H2 in Catalytic Bromate Reduction by Nanoscale Heterogeneous Catalysts.

The formation of bromate (BrO3-)in groundwater treatment is still a severe environmental problem. Catalytic hydrogenation by nanoscale heterogeneous catalysts with gaseous H2 or solid-state H2 has emerged as a promising approach, which relies on reducing BrO3- to innocuous Br- via the process of direct electron transfer or reduction with atomic hydrogen. Several nanocatalysts have demonstrated high efficiency with a 100% effective BrO3- reduction with greater than 95% of Br- generation in the batch and continuous reactors. However, this technology has not been widely adopted in water treatment systems. Indeed, this research article summarizes the advantages and disadvantages of these technologies by highlighting the factors of nanomaterials reduction efficiency, long-term durability, and stability, as well as addressing the essential challenges limiting the implementation of the use of H2 for BrO3- reduction. In this work, we provide an economic evaluation of catalytic BrO3- removal, safe hydrogen supply, storage, and transportation.

Competitive inhibition of catalytic nitrate reduction over Cu-Pd-hematite by groundwater oxyanions.

The presence of various oxyanions in the groundwater could be the main challenge for the successive application of Cu-Pd-hematite bimetallic catalyst to aqueous NO3- reduction due to the inhibition of its catalytic reactivity and alteration of product selectivity. The batch experiments showed that the reduction kinetics of NO3- was strongly suppressed by ClO4-, PO43-, BrO3- and SO32- at low concentrations (>5 mg/L) and HCO3-, CO32-, SO42- and Cl- at high concentrations (20-500 mg/L). The presence of anions significantly changing the end-product selectivities influenced high N2 selectivity. The selectivity toward N2 increased from 55% to 60%, 60%, and 70% as the concentrations of PO43-, SO32-, and SO42- increased, respectively. It decreased from 55% to 35% in the presence of HCO3- and CO32- in their concentration range of 0-500 mg/L. The production of NO2- was generally not detected, while the formation of NH4+ was observed as the second by-product. It was found that the presence of oxyanions in the NO3- reduction influenced the reactivity and selectivity of bimetallic catalysts by i) competing for active sites (PO43-, SO32-, and BrO3- cases) due to their similar structure, ii) blockage of the promoter and/or noble metal (HCO3-, CO32-, SO42-, Cl- and ClO4- cases), and iii) interaction with the support surface (PO43- case). The results can provide a new insight for the successful application of catalytic NO3- reduction technology with high N2 selectivity to the contaminated groundwater system.