The hopcalite (CuMnOx) catalyst is a well-known catalyst for CO oxidation at a low temperature and it is synthesized by the co-precipitation method with different types of precursors. Activity of the CuMnOx catalysts for CO oxidation is strongly dependent upon the combination of precursors, ranking in order {Mn(Ac) 2 + Cu(NO 3 ) 2 } > {Mn(Ac) 2 + Cu(Ac) 2 } > {Mn(N O 3 ) 2 + Cu(NO 3 ) 2 } > {Mn(NO 3 ) 2 + Cu(AC) 2 }. All the precursors were precipitated by KMnO 4 solution and the precursors mostly comprised of MnO 2 , Mn 2 O 3 and CuO phases. Keeping the same precipitant while changing the precursors caused a change in the lattice oxygen mobility which influenced the CO oxidation activity. The calcination strategy of the precursors has great influence on the activity of resulting catalysts. The reactive calcination (RC) conditions produce multifarious phenomena of CO oxidation and the precursor decomposition in a single-step process. The activity order of the catalysts for CO oxidation was as follows: reactive calcination (RC) > flowing air > stagnant air. Therefore, we recommended that the RC route was the more appropriate calcination route for the production of highly active CuMnOx catalysts. All the catalysts were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, X-ray photoelectron spectroscopy and scanning electron microscopy technique. The influence of precursors on the structural properties and the catalytic activity of co-precipitation derived binary CuMnOx catalysts for CO oxidation has been investigated.

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Biosorption of lead (II), copper (II) and cadmium (II) ions from aqueous solutions onto olive leaves powder has been investigated. The biosorption of lead (II), copper (II), and cadmium (II) was found to be dependent on solution pH, initial metal ion concentrations, biosorbent dose, contact time and temperature. The experimental equilibrium biosorption data were analyzed by two widely used two-parameters, Langmuir and Freundlich isotherm models. The Langmuir model gave a better fit than the Freundlich model. The kinetic studies indicated that the biosorption process of the metal ions followed well pseudo-second-order model. The thermodynamic parameters Gibbs free energy, ∆G• , enthalpy, ∆H • , and entropy, ∆S• were also calculated, and the values indicated that the biosorption process was endothermic and spontaneous in nature. It was concluded that olive leaves powder can be used as an effective, low cost, and environmentally friendly biosorbent for removal of Pb(II), Cu(II) and Cd(II) ions from aqueous solution.

Biosorption of Cr(VI) ions from aqueous solutions and electroplating wastewater by walnut shell powder has been investigated in a batch biosorption process. The biosorption of Cr(VI) ions was found to be dependent pH, initial chromiu m ion concentrations, biosorbent dose, contact time and temperature. The experimental equilib riu m biosorption data were analy zed by Lang muir, Freundlich, and Temkin isotherm models. The Lang muir model gave a better fit than the Freundlich and Temkin models. The ma ximu m biosorption capacity calculated from the Langmu ir isotherm was 138.89 mg/g at optimu m conditions. The kinetic studies indicated that the biosorption process of the chromiu m ions fo llo wed well pseudo-second-order model. The negative values of ∆G o (-3.51 kJ/ mo l) and positive value of ∆H o (12.95 kJ/ mol) revealed that the biosorption process was spontaneous and endothermic. Biosorption process was successfully applied to the treatment of an electroplating wastewater sample, where the concentration of chro miu m (VI) ions, organic materials and COD were effectively reduced. According to the sorption capacity, walnut shell powder considered as an effective, low cost, and environmentally friendly biosorbent for the removal of Cr(VI) ions fro m aqueous solution and electroplating wastewater.

The experimental densities ρ, and viscosities η, of binary mixtures of 2-pyrrolidone with butanol isomers: 1-butanol, 2-methyl-1-propanol, 2-butanol, and 2-methyl-2-propanol have been measured at T = (293.15, 298.15, and 303.15) K and atmospheric pressure over the whole mole fraction range. From these data, excess molar volumes, V E, and viscosity deviations, η, have been calculated at various temperatures. Both excess molar volumes and viscosity deviations are negative for all investigated systems. The excess molar enthalpies, H E, measured at 298.15 K and at atmospheric pressure for the four systems are positive over the whole mole fraction range. The experimental results have been correlated using Redlich−Kister polynomial equation, and parameters from least-squares analysis have been reported.