Summary:The petroleum has become our most important source of energy since the mid-1950s. It is due to its high energy density, easy transportability and relative abundance. However, along extraction, storage or transportation of oil, spill accidents may happen. This kind of accident causes severe impacts on the environment, being directly responsible for the destruction of the marine life, which affects the fishing and even tourism industries. Main goal of this work is related to the use of renewable sources aiming to obtain ''absorbent green materials''. These materials were synthesized by a typical phenolic resin polycondensation route using cashew nut shell liquid (CNSL) as main phenolic compound. Focused on keep the green characteristic of the materials, furfuraldehyde from hemicellulose was used as aldehyde and the reaction was catalyzed using a small amount of sulfuric acid. Resins were characterized using Optical Microscopy, Scanning Electron Microscopy, Infrared Spectroscopy with Fourier Transformed (FTIR) and density tests. In addition, contraction of the oil spilled was studied in presence of resins. Obtained results demonstrated that synthesized resins present a good chemical similarity with oil, which produces a good interaction among resins and oil, making easy the contraction of the oil spot on the water and, consequently, the removal process of oil spilled on water.
Hydrotalcite is a layered double hydroxide (LDH) consisting of brucite-like sheets of metal ions (Mg-Al). In this work, hydrotalcites were synthesized, and boron removal from oilfield wastewater was evaluated. LDHs were synthesized using the co-precipitation method. The calcined products (CLDHs) were obtained by heating at 500°C and characterized using X-ray diffraction, X-ray fluorescence, thermogravimetric analysis and the specific surface area (BET). The affinity of LDHs for borate ions was evaluated for calcined and uncalcined LDHs as a function of contact time, initial pH of the oilfield wastewater (pH ∼ 9) and the LDH surface area. The tests were conducted at room temperature (approximately 25ºC). The results indicated that 10 min were needed to reach a state of equilibrium during boron removal for calcined LDHs due to the high surface area (202.3 m(2) g(-1)) regardless of the initial pH of the oilfield wastewater, which resulted from the high buffering capacity of the LDHs. The adsorption capacity increased as the adsorbents levels increased for the range studied. After treatment of the oilfield wastewater containing 30 mg L(-1) of boron with Mg-Al-CO3-LDHs, the final concentration of boron was within the discharge limit set by current Brazilian environmental legislation, which is 5 mg L(-1). Pseudo-first-order and pseudo-second-order kinetic models were tested, and the latter was found to fit the experimental data better. Isotherms for boron adsorption by CLDHs were well described using the Langmuir and Freundlich equations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.