Tuning the redox potential of vitamin K3 derivatives by oxidative functionalization using a Ag(i)/GO catalyst.

We propose herein initial results to develop optimum redox mediators by the combination of computational simulation and catalytic functionalization of the core structure of vitamin K3. We aim to correlate the calculated energy value of the LUMO of different vitamin K3 derivatives with their actual redox potential. For this, we optimized the catalytic alkylation of 1,4-naphthoquinones with a designed Ag(i)/GO catalyst and synthesized a series of molecules.

Removal of heavy metals via adsorption on activated carbon synthesized from solid wastes.

The huge quantity of date pits as solid waste byproduct in Saudi Arabia pose a problem as they are difficult to biodegrade. The potential of using date pits as a cheap precursor to prepare activated carbons was investigated. Steam as well as zinc chloride activated carbons were prepared from dates pit. The textural properties, including surface area, mean pore radius and total pore volume, were determined from the adsorption of nitrogen at 77 K. FT-IR spectroscopy and base neutralization capacity were used to determine the surface groups. The adsorption of Cu2+, Pb2+ and Cd2+ was studied in equilibrium method. FT-IR investigation of un-activated carbons identified phenolic, lactonic, -O-H, quinonic and carboxylate groups. For steam and zinc chloride activated carbons, some of the adsorption bands either disappeared or become less predominant, depending on the acidic or basic nature of the surface. The measurements of BNC indicated that steam activated carbons were predominately basic, while zinc chloride activated carbons exhibited acidic nature. Physical and chemical activation increase the porosity and thereby develop a higher surface area. The adsorption of Cu2+, Pb2+ and Cd2+ followed the order Pb2+ > Cu2+ > Cd2+. Zinc chloride activated carbons had a higher adsorption power compared with steam activated carbons. The adsorption behavior was affected by the textural and chemistry of the surface.

Comparative study for the removal of methylene blue via adsorption and photocatalytic degradation.

Physically and chemically activated carbons were prepared from date pits and olive stones. Titania and WO(x)-TiO(2)/MCM-41 were prepared as photoactive catalysts. Surface characterizations were investigated from ash content, pH, base neutralization capacities and FT-IR techniques. The textural characteristics, namely specific surface area (S(BET)) and pore texture, were determined from low temperature adsorption of N(2) at 77 K. The decolorization of aqueous solution of methylene blue was performed by means of two alternative methods. Steam-activated carbons own higher surface area compared with ZnCl(2)-activated carbons, and the micropore surface area represents the major contribution of the total area. Steam-activated carbons were the most efficient decolorizing adsorbents owing to its higher surface area, total pore volume and the basic nature of the surface. The calculated values of DeltaG(0), DeltaH(0) and DeltaS(0) indicate the spontaneous behavior of adsorption. The photocatalytic degradation is more convenient method in decolorizing of methylene blue compared with the adsorption process onto activated carbons.