Fabrication and characterization of MgCo2O4 for solid phase extraction of Pb(II) from environmental samples and its detection with high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS)

Ionic liquids (ILs) have been shown to affect cellulose crystalline structure in lignocellulosic biomass during pretreatment. A systematic investigation of the swelling and dissolution processes associated with IL pretreatment is needed to better understand cellulose structural transformation. In this work, 3–20 wt % microcrystalline cellulose (Avicel) solutions were treated with 1-ethyl-3-methylimidazolium acetate ([C₂mim][OAc]) and a mixture of [C₂mim][OAc] with the nonsolvent dimethyl sulfoxide (DMSO) at different temperatures. The dissolution process was slowed by decreasing the temperature and increasing cellulose loading, and was further retarded by addition of DMSO, enabling in-depth examination of the intermediate stages of dissolution. Results show that the cellulose I lattice expands and distorts prior to full dissolution in [C₂mim][OAc] and that upon precipitation the former structure leads to a less ordered intermediate structure, whereas fully dissolved cellulose leads to a mixture of cellulose II and amorphous cellulose. Enzymatic hydrolysis was more rapid for the intermediate structure (crystallinity = 0.34) than for cellulose II (crystallinity = 0.54).

Impact of Ionic Liquid Pretreatment Conditions on Cellulose Crystalline Structure Using 1-Ethyl-3-methylimidazolium Acetate B

Adsorption of crude oil from aqueous solution: A review

It is increasing the preoccupation with the estuary system due to the importance that it presents and its unique environmental characteristics that result in high biological productivity. In this work we analyze the impacts caused in Santos Estuary System by the port activities. In the lasts years, urban settings and the development of industrial, port, fishing activities, mineral exploration, tourist activities, and others, without adequate planning, comes placing in scratch the basic attributes Brazilian estuaries and ecosystems associates, resulting in local population life quality decrease.

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Impactos das atividades portuárias no sistema estuarino de Santos / Impacts of activities in port system estuarine Santos

This review provides an overview and discusses analytical strategies for the preconcentration of trace elements using lignocellulosic sorbents for solid-phase extraction. This procedure is widely used for the determination of metals and metalloids in different types of samples due to its simplicity, rapidity, minimal waste generation, reduction of sample matrix effects as well as sorption of the target species on the solid surface. For this purpose, some inorganic, organic, and several natural adsorbents are used. New approaches to obtaining adsorbent materials from natural sources such as agro-industrial residues and composting materials have received attention. The most used lignocellulosic materials as sorbents for solid-phase extraction are bagasse sugarcane, cotton, sisal, palm fiber, coconut, corn cob, soybean straw, jute, and rice. The lignocellulosic materials have been investigated because the presence of functional groups in their structures is made up of lignin and cellulose. These materials have been used in the development of analytical methods with the varied proposal, such as preconcentration or speciation of analytes. 

Lignocellulosic materials as adsorbents in solid phase extraction for trace elements preconcentration

Determination of Cu, Ni, Mn and Zn in diesel oil samples using energy dispersive X-ray ﬂuorescence spectrometry after solid phase extraction using sisal fiber.

This work evaluates the adsorption capacity of the wild cane fiber (Gynerium Sagittatum) in crude oil. Both untreated biomass and treated with ionic liquid [2HEA][Ac] and acetylated were studied for oil spill cleanup in aqueous environment. Crude oil adsorption tests were performed in a thermostatic bath, varying the time for the kinetic study and the amount of oil for isotherm model. Kinetic study of oil adsorption allowed us to identify that the untreated fiber reached saturation in 90 minutes, while the fiber treated with acetylated and ionic liquid reached saturation in 30 minutes. In equilibrium, the total amount of oil adsorbed by the untreated fiber was 3.8g, whereas in acetylated and ionic liquid treated fiber, the obtained maximum adsorption capacity was 4.4 and 3.7 g, respectively. The remediation process using wild cane fiber followed a second order kinetic rate and Sips and Toth isotherm models provided the best fit to experimental data.

http://www.portalabpg.org.br/bjpg/index.php/bjpg/article/download/714/356

Adsorption of crude oil in aqueous environment using wild cane fiber: equilibrium and kinetic studies

One way to take advantage from out-of-specification biodiesel and waste from biodiesel tank bottom drainage is to co-process them in a fluidized catalytic cracking (FCC) unit. The present work deals with the cracking of oleic acid methyl ester (OAME) as a biodiesel model, under conditions close to that of FCC process over ZSM-5 and Y zeolites, either in protonated or sodium forms, towards deoxygenated compounds. Catalytic fast cracking of OAME pre-adsorbed on the catalyst surface was performed, with a catalyst:OAME mass ratio of 10:1 in a micro-pyrolysis system at 650 °C, coupled to a GC/MS for on line analysis of the products. Results show that the cracking of OAME without a catalyst favored the formation of linear alkenes and polyenes. Fast cracking of OAME over HZSM-5 and HY acidic zeolites led to the production of aromatics, due to hydrogen transfer. Cracking over NaY and HY zeolites produced remarkable amounts of ramified saturated hydrocarbons. The formation of alkylated hydrocarbons was not significant over ZSM-5 zeolite probably due to a small pore size of this zeolite. NaY catalyst favored the production of hydrocarbons in the range of kerosene (C8–C12). Low acidic zeolites favored the production of non-aromatic hydrocarbons. Product distribution was affected by catalyst shape selectivity and acidity. These results suggest that residues from the biodiesel chain can be directly co-processed in FCC units to obtain high value hydrocarbons, mainly in the jet fuel and gasoline ranges.

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Alane P. Santos

Papers

Determination of Cu, Ni, Mn and Zn in diesel oil samples using energy dispersive X-ray ﬂuorescence spectrometry after solid phase extraction using sisal fiber.

Adsorption of crude oil in aqueous environment using wild cane fiber: equilibrium and kinetic studies

Deoxygenation of Oleic Acid Methyl Ester in FCC Process Conditions Over Protonated and Sodium Exchanged Y and ZSM-5 Zeolites