Polyoxometalate (POM) catalysts with different trivalent hetero ions (Mn+ = Fe3+, Al3+, and Cr3+) were prepared by incipient wetness impregnation method and supported on different zeolites namely, NaY, ZSM-5 and Mordenite. The intended catalysts samples were distinguished by X-ray diffraction, FTIR and surface texture measurements. The data given disintegration in the crystallinity of zeolite structure, enlarge in particle size and new phases of metal oxides Al2(MoO4)3 and Fe2(MoO4)3 were exposed by XRD and FTIR techniques. These phases caused widening of pores of the employed zeolites and change of the surface texture. The physical changes indicate the considerable interaction of polyoxomolybdate with the zeolite structure. The assessment of the catalytic activity was thorough by applied the photocatalytic degradation of direct blue 1 dye (DB1) in existence of H2O2 as a green oxidant. The catalytic activity of Mn+Mo-ZSM-5 sample is higher than that of Mn+Mo-Y or Mn+Mo-Mord.

This study reports on the adsorption efficiency of a natural iron oxide from Mballam-Cameroon in comparison with synthesized goethite to simulta-neously remove cobalt and nickel ions from aqueous solutions. Chemical analysis on the natural iron oxide sample revealed iron as the main element and hematite (58.52%) goethite (19.42%), kaolinite (12.69%) and quartz (7.79%) as the component phases in the iron oxide sample. The iron oxide was found to be microporous (BET surface area 43.27 m2/g) with fairly spherical polydisperse particles. Results show maximum absorption for Co(II) and Ni(II) ions for both adsorbents occurred at an equilibrium contact time of 80 mins, dose rate of 0.1 g/L, and pH = 7. Goethite was slightly more efficient at removing target metal ions with maximal adsorbed quantities at 117.8 mg/g of Co(II) and 100.6 mg/g of Ni(II), and 103.9 mg/g of Co(II) and 85.2 mg/g of Ni(II) ions for natural iron oxide. Equilibrium modelling presented the Freundlich isotherm as the best fit model for both adsorbents and metal ions, indicating heterogeneity of the surface binding sites during adsorption. The pseudo-second order kinetic model was the best-fit model, indicating chemical adsorption between the adsorbent surface and metal ions, hence a good correlation between equilibrium and kinetics. The findings indicate that the efficacy of the natural iron oxide from Mballam is almost equivalent to that of synthetic goethite, validating its applicability for the simultaneous removal of cobalt and nickel ions from aqueous solution.

Commercial silicoaluminophosphate molecular sieves (SAPO-34) received alkali treatment with either NaOH (0.2, 0.01, 0.005, or 0.001 M) or NH4OH (0.005 M). Treatment with NaOH (0.005 M) increased the water adsorption initial rate of SAPO-34 by 1.4-fold. The alkali treatment introduced Na+ adsorption sites into the SAPO-34. The desorption ratio (adsorption at 30°C and desorption at 100°C) was 88.2% higher than the original rate (84.3%). On the other hand, after alkali treatment of SAPO-34 using NH4OH (0.005 M), calcination resulted in the highest desorption ratio at 91.3%. When combined with calcination, alkali treatment with NH4OH introduced H+adsorption sites into SAPO-34, H+ adsorption sites feature low levels of interaction with water, which enhanced the desorption ratio, but decreased the initial adsorption rate. These results indicate that treating commercial SAPO-34 with 0.005 M NaOH enhances both the adsorption and desorption behaviors.

In this study, it was to investigate the swelling performance of novel biohybrid composite hydrogel sorbents containing acrylamide/potassium 3-sulfopropyl methacrylate/sodium alginate/bentonite in water and binary mixtures of water-solvent. Novel hydrogels were synthesized with free radical solution polymerization by using ammonium persulfate/N,N,N’,N’-tetramethylethylenediamine as redox initiating pair in presence of poly(ethylene glycol) diacrylate as crosslinker. Swelling experiments were performed in water and binary mixtures of water-solvent (acetone, methanol and tetrahydrofuran) at 25°C, gravimetrically. Some swelling and diffusion properties of the hydrogels were calculated and they were discussed for the biohybrid/hybrid hydrogel systems prepared under various formulations. It has been seen the lower equilibrium percentage swelling ratio values (62% - 124%) in all solvent compositions in comparison with the equilibrium percentage swelling ratio values in water (718% - 2055%). Consequently, the hydrogel systems developed in this study could serve as a potential device for water and water-solvent binary mixtures.

Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [RF-(CH2CHSi(OMe)3)n-RF; RF = CF(CF3)OCF7, n = 2, 3; RF-(VM)n-RF] was applied to the preparation of fluoroalkyl end-capped vinyltrimethoxysilane oligomer/α-, β-, γ-cyclodextrin polymers (α-, β-, γ-CDPs) composites [RF-(VM-SiO2)n-RF/α-, β-, γ-CDPs] by the sol-gel reaction of the corresponding oligomer in the presence of the α-, β-, γ-CDPs under alkaline conditions. The RF-(VM-SiO2)n-RF/α-, β-, γ-CDPs composites thus obtained were found to give a good dispersibility toward the traditional organic media except for water, and were applied to the surface modification of glass to provide a sueperoleophilic/superhydrophobic characteristic on the modified surface, although the corresponding RF-(VM-SiO2)n-RF nanocomposites can give a usual oleophobic/superhydrophobic property on the surface. These composites powders were also found to be applicable to the packing material for the column chromatography to separate the mixture of oil/water and the water in oil (W/O) emulsions. More interestingly, these composite powders were found to have a higher adsorption ability toward not only low-molecular weight aromatic compounds such as bisphenol A and bisphenol AF but also volatile organic compounds, compared to that of the pristine α-, β-, γ-CDPs.

Encapsulation confers protection to substances as essential oils from processes like oxidation, evaporation or uncontrolled release. In this study almond oil capsules were obtained by co-extrusion/gelling technique. Chitosan was used as shell material and sodium triphosphate pentabasic as cross linking agent. Different encapsulation process variables were studied: cross-linker concentration, nozzles size and potential. Optical microscopy was used to determine the capsules morphology and degradability tests were performed in order to study capsules degradation over time. Results showed that nozzles size and cross linking concentration are key variables to consider in the encapsulation process. Degradability tests showed rapid weight loss.

Microspheres containing Pioglitazone hydrochloride were prepared by the ionotropic external gelation method, using sodium alginate with four mucoadhesive polymers namely sodium carboxy methyl cellulose, hydroxy propyl methyl cellulose, carbopol 934 P and cellulose acetate phthalate as coat materials. Ionotropic gelation is a method to prepare microspheres using combination of Ca2+ as cationic components and alginate as anion. The practical yield of prepared microspheres using the ionotropic gelation technique was between 172 mg and 604 mg. The result of the Chi-squared test carried out between the actual (practical) and expected (theoretical) yields showed no significant difference (P ex-vivo wash-off test shows the best mucoadhesive property. The in vitro drug release studies do up to 18 h. As observed from the various plots, most of the formulations followed the Korsmeyer-Peppas model.

In dentistry, a wide range of materials is available for restorative treatment; a typical product of such restorative materials mainly consists of radically polymerizable monomer(s) and inorganic filler(s) (for added physical strength), as well as a surface modifier (e.g. silane coupling agent) for improved affinity between monomer and filler. It is favorable to use an optimal surface modifier depending on the respective restorative materials. However, commercially available surface modifiers, which are synthesized by the ton, are not always suited for what is required for properties of the many different dental restorative materials. As a potential solution to such a problem, we focused on the latest technology, “micro flow reactors” that enabled an on-demand low-volume synthesis of many types of surface modifiers. Using micro reaction fields of such flow reactors, we synthesized a novel long-chain silane coupling agent. Compared to the control system synthesized using a conventional reaction flask, the novel system enabled significant reduction in reaction time without inducing any major side reactions. A dental composite resin that was treated with the novel coupling agent exhibited higher toughness, suggesting that such a silane coupling agent was an effective surface modifier.

Inhibition performance of norepinephrine was investigated as corrosion inhibitors by Gravimetric technique and carried out with mild steel samples in 1 M hydrochloric acid solution at room temperature. Norepinephrine exhibited maximum efficiency of 79% at 500 mg/L. The results of Gravimetric studies revealed that the investigated compound acted as good corrosion inhibitor and the inhibition efficiencies increased with increase in the concentrations of the inhibitor IC. The experimental data complied with the Langmuir adsorption isotherm. Thermodynamic parameters, such as ΔGo, ΔHo, and ΔSo, were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm. Results suggested that the norepinephrine adsorption on mild steel surface was a spontaneous and exothermic process. Scanning electron microscopy was used to investigate the mild steel surface at the highest corrosion inhibition studied concentration.

An essential oil is the volatile lipophilic component extracted from plants. Microencapsulation systems protect the essential oil from degradation and evaporation, and, at the same time, allow a sustained release. This work analyses and characterizes the oregano and sage essential oil microcapsules prepared by interfacial polymerization technique, using polyurea as wall material. Several instrumental techniques are used: optical microscopy, size particle, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), Termo gravimetric analysis (TGA), spectrophotometry, antimicrobial test and chromatography. Results show that oregano and sage oil have antimicrobial properties, and their microencapsulation allows knowing that these properties remain inside the microcapsules.