Browsing by Author "Sgorlon, Juliana"
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- Imidazolium chloride ionic liquid mixtures as separating agents: fuel processing and azeotrope breakingPublication . Vilas-Boas, Sérgio M.; Martins, Mónia A.R.; Tentor, Fabio Ribeiro; Teixeira, Gabriel; Sgorlon, Juliana; Coutinho, João A.P.; Ferreira, Olga; Pinho, SimãoRelevant chemical separations for the petrochemical and chemical industries include the removal of aromatic hydrocarbons from aliphatics, the desulfurization and denitrification of fuels, and the separation of azeotropic mixtures containing alkanols. In an attempt to contribute to the development of novel technologies, the potentialities of imidazolium chloride ionic liquid (IL) mixtures as separation agents were investigated. Selectivities, capacities, and solvent performance indices were calculated through the activity coefficients at infinite dilution of organic solutes and water in the imidazolium chloride IL: [C8mim]Cl, [C12mim]Cl, and the equimolar mixture of [C4mim]Cl and [C12mim]Cl. Results show that the imidazolium chloride IL might be appropriately tailored for specific purposes, in which an increase in the proportion of cations containing larger alkyl chains tends to increase the overall affinity with organic solutes. The IL designer solvent concept was explored by comparing the IL equimolar mixture results with the intermediary [C8mim]Cl. The COSMO-RS thermodynamic model was also applied, showing it to be a promising tool for a fast qualitative screening of potential separation agents for specific separation processes.
- Synthesis and characterization of clay-based catalysts prepared from natural claysPublication . Silva, Adriano S.; Díaz de Tuesta, Jose Luis; Gomes, Helder; Sgorlon, JulianaThis work deals with the synthesis and characterization of clay-based catalysts. The catalysts prepared in this work were clays activated through acid treatment and clays pillared with Co and Fe. For the preparation, natural clays from four different regions of Kazakhstan were used: Akzhar, Asa, Karatau and Kokshetau. The FTIR analysis showed that the pillared clays have an amount of iron in its structure. The N2 adsorption isotherms obtained were classified as Type II, according to IUPAC classification, typical of macroporous materials. The SBET calculated with the N2 adsorption isotherms for the activated clays showed to be higher than the SBET results for natural clays. XRD patterns helped to gather information about crystalline phases of the clay, allows classifying the type of clay used in the work. The acid characterization showed that the procedures used for the preparation of the acid activated clays and pillared clays caused structural modifications, which is another result that suggests the success of both methods.
- Wet peroxide oxidation of paracetamol using acid activated and Fe/Co-pillared clay catalysts prepared from natural claysPublication . Silva, Adriano S.; Kalmakhanova, Marzhan; Massalimova, Bakytgul Kabykenovna; Sgorlon, Juliana; Díaz de Tuesta, Jose Luis; Gomes, HelderMany pharmaceuticals have been recently identified at trace levels worldwide in the aquatic environment. Among them, the highly consumed paracetamol (PCM), an analgesic and antipyretic drug, is largely being accumulated in the aquatic environment due to ine cient removal by conventional sewage treatment plants. This work deals with the treatment of PCM, used as a model pharmaceutical contaminant of emerging concern, by catalytic wet peroxide oxidation using clay-based materials as catalysts. The catalysts were prepared from natural clays, extracted from four di erent deposits using acid-activated treatment, calcination, and pillarization with Fe and Co. Pillared clays show the highest catalytic activity owing to the presence of metals, allowing to remove completely the PCM after 6 h under the following operating conditions: CPCM = 100 mg L1, CH2O2 = 472 mg L1, Ccat = 2.5 g L1, initial pH = 3.5 and T = 80 C. The prepared materials presented high stability since leached iron was measured at the end of reaction and found to be lower than 0.1 mg L1.
- Wet peroxide oxidation of paracetamol using Fe/Co-pillared clay catalysts prepared from natural claysPublication . Silva, Adriano S.; Roman, Fernanda; Kalmakhanova, Marzhan; Sgorlon, Juliana; Díaz de Tuesta, Jose Luis; Gomes, HelderThis work deals with the catalytic wet peroxide oxidation of paracetamol, considered as model emerging pollutant, using as catalysts low-cost materials based on pillared clays prepared from natural clays. Pillared clays were prepared successfully through a pillaring solution containing cobalt and iron. The prepared clays allow to remove completely the pollutant after 8 h of reaction at 80 ºC, initial pH 3.5, Ccatalyst = 2.5 g L-1, Cpollutant = 100 mg L-1 and CH2O2 = 472 mg L-1, whereas in the non-catalytic run only 20% removal of pollutant was obtained after 24 h at the same operating conditions.
- Wet peroxide oxidation of paracetamol using natural clay-based materials as catalystsPublication . Silva, Adriano S.; Díaz de Tuesta, Jose Luis; Sgorlon, Juliana; Kalmakhanova, Marzhan; Gomes, HelderIn recent years, many pharmaceutical compounds have been identified worldwide at trace levels (in the order from ng·L·1 to mg·L-1) in the aquatic 12nvironment [1]. The presence of pharmaceutical contaminants in water, even at low concentrations, could bring harmful toxicological consequences to human beings and animals that ingested the contaminated water [2]. This work deals with the treatment of water containing paracetamol (PCM) by catalytic wet peroxide oxidation (CWPO) using clay-based materials as catalysts. PCM was considered as a model pharmaceutical emergent pollutant. For the preparation of the catalysts, natural clays from four different regions of Kazakhstan were used Akzhar, Asa, Karatau, and Kokshetau. From the clay obtained in kokshetau deposit, three catalysts were prepared: 1) natural one (KON), 2) calcined clay at 600 °C for 5 h (KOC), and 3) a pillarized clay (KOP) with a pillaring solution containing 0.25 M CoCI2, 0.5 M FeCI3 and 0.5 M NaOH, resulting in OH/(Fe+Co) = 2:1. Additionally, three clays were ptrepared by the same procedure of pillarization from the Akzhar, Asa and Karatau natural clays, resulting in AKP, ASP, and KAP, respectively. The concentration of PCM, H20 2 and total organic carbon (TOC) were followed during the CWPO experiments (Fig. 1 ). All materials revealed high catalytic activity, the non-pillared samples allowing to remove more than 33.4% of PCM after 24 h of reaction time under the following operating conditions: 80 °C, initial pH 3.5, Ccatalyst = 2.5 g L-1, CPCM = 100 mg L-1 and CH202 = 472 mg L-1. The CWPO runs done with the pill a red clay catalysts resulted in more than 90% of removal of the pollutant after 24 h of reaction. The best catalyst was KOP since it leads to the complete removal of the pollutant after 8 h of reaction time and to the highest abatement of TOC (>60%) under the same operational conditions.