No abstract

This work presents the conditions for Pb(II) and Cd(II) removal from aqueous solution using two different sorbent materials, namely, clinoptilolite and Opuntia ectodermis, which were characterized before and after entering into contact with the metal-containing aqueous media, using scanning electron microscopy (SEM), thermal analysis (TGA) and surface area (BET). Metal removal was found to depend on the initial metal concentration in aqueous solution, pH and the mass/volume ratio. The Pb(II) and Cd(II) uptake process was maximum at pH 4 for both sorbents, which showed an adsorption capacity that was adequately described by the Freundlich adsorption isotherm. The Thomas model was used to describe the adsorption data from column studies, the sorption capacity was 12.21 Pb(II) mg per gram of Opuntia ectodermis, while 7.71 Pb(II) mg per gram of clinoptilolite were adsorbed; lower values were obtained for Cd(II) removal. It was demonstrated that the use of low cost materials for the treatment of Pb(II), and Cd(II), containing wastewater is an effective and economical alternative method.

No abstract

This work presents conditions for hexavalent chromium (Cr(VI)) removal from aqueous solution using different sorbent materials, namely: pyrolytic ashes of an industrial sludge from wastewater treatment and roots of Typha latifolia. The sorbent materials were characterized using scanning electron microscopy (SEM) and surface area using the Brunauer-Emmett-Teller (BET) technique, before and after the contact with the chromium-containing aqueous media. An overall Cr(VI) concentration reduction of 45% was achieved using the roots of Typha latifolia whereas in the case of pyrolytic ashes a 60% removal was observed. The percentage removal was found to depend on the initial Cr(VI) concentration in aqueous solution, pH and temperature. The Cr(VI) uptake process was maximum at pH 2 and a temperature of 40 degrees C for both sorbents. These materials showed a Cr(VI) adsorption capacity that was adequately described by the Langmuir adsorption isotherm. It was demonstrated that the use of waste materials for the treatment of Cr(VI)-containing wastewater is an effective and economical alternative method.

This work analyzes the mechanical behavior of new composite materials with polymeric matrix, made from recycled polyethylene terephthalate (r-PET), reinforced with 10, 20, 30 and 40 wt% Zn metal particles, processed under isothermal sintering at constant temperature (256°C) and time (15 min) conditions. The r-PET/Zn composite material samples were obtained by a powder traditional technique, namely, ball-milling, uniaxial dye-pressing to obtain pre-forms followed by isothermal sintering. The observations through optical microscopy of the overall morphologies that resulted after sintering the samples studied, were compared against the r-PET-control sample without reinforcement, processed under the same conditions. From the results, it was found that the metal particles were distributed uniformly in the matrix; further, increasing amounts of metal particles tended to improve the mechanical behavior resulting in a stronger material, as was the case of the two materials with higher metal contents (30 and 40 wt% Zn).

The corrosion inhibition efficiency of the new heterocycles is investigated on steel grade API 5L X52 in 1M HCl employing electrochemical impedance spectroscopy. -(CRUZ-GONZALEZ, D. Y.; GONZALEZ-OLVERA, R.; NEGRON-SILVA*, G. E.; LOMAS-ROMERO, L.; GUTIERREZ-CARRILLO, A.; PALOMAR-PARDAVE, M. E.; ROMERO-ROMO, M. A.; SANTILLAN, R.; URUCHURTU, J.; Synthesis 46 (2014) 9, 1217-1223, http://dx.

No abstract

No abstract