RESUMO O isolamento zonal inadequado em poços de petróleo pode provocar problemas de segurança e ambientais. Novas pastas de cimento podem evitar esses problemas. Neste trabalho, novas pastas de cimento foram preparadas na presença de água do mar com resina epóxi- etilenodiamina formada in situ. As novas pastas foram testadas em relação às suas propriedades mecânicas e caracterizadas por FTIR, DRX, TG / DTG, porosimetria por adsorção-dessorção de N2 e RMN 29Si e 27Al no estado sólido. Algumas características cinéticas do contato de longo prazo das pastas com fluido ácido gerado in situ foram realizadas para avaliar o desempenho das novas pastas em procedimentos rotineiros de acidificação na indústria de poços de petróleo. Os dados cinéticos experimentais foram bem ajustados ao modelo cinético exponencial de ordem-variável e a um planejamento fatorial de quatro variáveis (24). Nesses estudos, foi possível avaliar detalhadamente como alguns fatores experimentais importantes atuam sobre as quantidades de ácido que interagem com as pastas, bem como verificar como esses fatores afetam a velocidade com a qual o fluido ácido interage com as pastas. Os resultados sugerem fortemente que as interações ocorridas nas interfaces de pasta de cimento epoxi/ etilenodiamina-fluido ácido são devidas às reações na superfície das pastas de cimento com preservação das suas estruturas químicas, mesmo após contato prolongado com o fluido. As novas pasta de cimento apresentam boas características para ser usada em procedimentos ecológicos no campo de poços de petróleo.

ABSTRACT Inadequate zonal isolation in oil wells can provoke safety and environmental problems. New cement slurries can avoid such problems. In this work, novel cement slurries were prepared in the presence of seawater with in situ-formed epoxy resin–ethylenediamine. The new slurries were tested in relation to their mechanical properties and characterized by FTIR, XRD, TG/DTG, porosimetry by N2 adsorption-desorption and solid-state 29Si and 27Al NMR. Some kinetic features of long-term contact of the slurries with in situ-generated mud-acid were performed to evaluate the performances of the new slurries in routine acidizing procedures in oil well industry. The experimental kinetic data were well fitted to order-variable exponential kinetic model and a factorial design of four variables (24). In these studies, it was possible to evaluate in detail how some important experimental factors act on the quantities of acid that interact with the pastes, as well as to verify how these factors affect the speed with which the mud-acid interacts with the slurries. The results strongly suggest that the interactions occurred at epoxy/ethylenediamine cement slurry/mud-acid interfaces are due to surface reactions with preservation of the chemical structures of the cement slurries, even after long-term contact with mud-acid. The new cement slurry present good features to be used in environmental-friendly procedures in oil well field.

ABSTRACT Chemically-modified in natura collage was prepared under acidic catalysis for using in sorption of Cd(II) from aqueous solutions. Simultaneous determination of the quantity and energetic parameters of Cd(II) sorption on PGA-scale at pH 8.0 were determined using solution microcalorimetry (SM). The calorimetric enthalpies of Cd(II) sorption on PGA-scale are all exothermic, and Cd(II) adsorption energies decrease as temperature increases. The maximum sorption capacity of PGA-scale for Cd(II) (438 μmol g-1) is superior with many sorption data reported in the literature. Characterization and SM indicate that the main sites for Cd(II) sorption are located in the collagen structure of PGA-scale. It was found that the interactions PGA-scale/Cd(II) are mainly due to chemisorption and diffusion may occur at the PGA-scale/Cd(II) interface. The results of this study underline the good features of PGA-scale as a promising material for sorption of Cd(II) from aqueous media.

ABSTRACT It is known that wastewaters containing dyes are very difficult to treat, since many dyes are stable and recalcitrant molecules. In this way, sorption may suitable for effectively remove dyes in this specific application field. In this work, a first approach for using polymeric membranous collagen of fish scales for sorption of saline methylene blue dye (MB) solution found in subsurface procedures of oil well industry. From structural characterization, the sorbent was found to be a composite of fibrillar type I collagen and apatites. The MB sorption amounts decreased with temperature increasing, with maximum MB sorbed of 2.18 mmol g-1 at 25 0C. In most sorption tests, residual MB in saline water was undetectable within 200 min of contact time. The sorption kinetic data were well adjusted to a three-parameter multi-step exponential function. The good fitting of such function were only obtained taking into account the presence of time-dependent kinetic parameters. The proposed multi-step sorption mechanism involved surface interaction and diffusion of MB into the membranous collagen. The interaction of positively charged MB ions with the collagenous adsorbent occurred through electrostatic forces. The results point out the collagenous adsorbent for effective procedures of sorption of MB dyes from high-saline wastewaters.

Characterization of fish scales of Leporinus elongatus and their application in the removal of Cu(II) from aqueous solutions are described. It was observed that the scales are mainly formed by hydroxyapatite and type I collagen. Adsorption of Cu(II) was performed using batch experiments at 25 0C. The ANOVA statistical results have shown that the Langmuir model was successful applied to determine the maximum adsorption capacity of 2.686 x10-4 mol g-1 and the Langmuir equilibrium parameter (b) of 168.8 L mol-1. The Langmuir separation parameter, R L, has shown favorable adsorption of Cu(II) on the scales.