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Laboratory for Process Engineering, Environment, Biotechnology and Energy
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Assessment of the Potential of Using Nanofiltration Polymeric and Ceramic Membranes to Treat Refinery Spent Caustic Effluents
Publication . Rita, Ana Isabel; Nabais, Ana Rita; Neves, Luísa A.; Huertas, Rosa; Santos, Maria; Madeira, Luís M.; Sanches, Sandra; DQ - Departamento de Química; LAQV@REQUIMTE; MDPI AG
Spent caustic effluents are very challenging due to their very hazardous nature in terms of toxicity as well as their extreme pH (approximately 12–14). Spent caustic has presented a challenge for wastewater treatment in refineries, due to its composition rich in mercaptans, sulfides and other aromatic compounds. To address such problems, membrane filtration was studied using real effluents from Sines Refinery, in Portugal. The present study attempts to assess the potential for spent caustic treatment with nanofiltration (NF) polymeric and ceramic membranes, assessing membrane life expectancy. For that, membrane aging studies in static mode were performed with the polymeric membrane before attempting NF treatment (dynamic studies). A ceramic membrane was also tested for the first time with this type of effluents, though only in dynamic mode. Although the polymeric membrane performance was very good and in accordance with previous studies, its lifespan was very reduced after 6 weeks of contact with spent caustic, compromising its use in an industrial unit. Contrarily to expectations, the ceramic membrane tested was not chemically more resistant than the polymeric one upon direct contact with spent caustic (loss of retention capacity in less than 1 h in contact with the spent caustic). The results obtained suggest that a pH of 13.9 is very aggressive, even for ceramic membranes.
Study, development and implementations of methodologies that allow optimizing refinery wastewater treatment processes and minimize impact risks on the surrounding
Publication . Rita, Ana Isabel Batista; Sanches, Sandra; Madeira, Luís; Santos, Maria António
The main objective of the work developed in this thesis was to address spent caustic treatment as a way to decrease the high organic load of this effluent and reduce its great impact on the quality of the wastewater sent to wastewater treatment plants, particularly in terms of oil and grease (O&G) contamination. The naphthenic spent caustic generated by Galp refinery in Sines was used as case study.
Spent caustic effluents are very challenging due to their very hazardous nature in terms of toxicity as well as their extreme pH (approximately 12-13). Spent caustic treatment is presently a challenge for refineries, due to its composition rich in mercaptans, sulphides and other aromatic compounds. In general, proton nuclear magnetic ressonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and gas chromatography mass spectromery (GC-MS) analyses suggested that aromatic structures account for a significant part of the organic structures that constitute naphthenic spent caustic, which are also present in the final wastewater. It was found that acid crudes processing with lower molecular-weight acid components seem to have a great impact on polar O&G concentration increase in spent caustic and therefore in the final wastewater.
Nanofiltration (NF) is a very effective technology when treatment and separation/recovery of specific components is required since it is able to remove low molecular weight organic molecules like hydrocarbons and phenolic compounds. The potential application of polymeric and ceramic membranes was addressed by conducting ageing studies (only in the case of polymeric membranes) and NF experiments to assess their retention properties and lifespan. Contrarily to expectations, neither of the tested types of membranes presented attractive results for spent caustic treatment, due to very quick losses of their retention properties; analysis by FT-IR and Inductively coupled plasma atomic emission spectroscopy (ICPAES) corroborated the ocurrence of desintegration mechanisms in the structure of the tested membranes. A different strategy based on chemical treatments was followed to treat spent caustic: (i) neutralization, followed by Fenton oxidation post-treatment (approach 1) and (ii) neutralization, followed by liquid-liquid extraction (approach 2). Approach 1 (lab scale tests) allowed to remove 95 % of polar O&G, with a 70% decrease in the acute toxicity after treatment. Approach 2 (pilot scale tests) allowed to remove 99 % of polar O&G. Both technologies allowed direct discharge of treated spent caustic into the Sines refinery wastewater circuit, with approach 2 being the best option since it presented the highest annual savings (1.5 yearly effluent management cost.
The results obtained in the present thesis may be useful for the development/optimization of industrial-scale plants in petroleum refineries for the treatment of naphthenic spent caustic effluents, providing an effective treatment technology proposal, with interesting effluent management cost reduction.
Helicobacter pylori lipopolysaccharide structural domains and their recognition by immune proteins revealed with carbohydrate microarrays
Publication . Silva, Lisete M.; Correia, Viviana G.; Moreira, Ana S. P.; Domingues, Maria Rosário M.; Ferreira, Rui Manuel; Figueiredo, Céu; Azevedo, Nuno F.; Marcos-Pinto, Ricardo; Carneiro, Fátima; Magalhães, Ana; Reis, Celso A.; Feizi, Ten; Ferreira, José A.; Coimbra, Manuel A.; Palma, Angelina S.; UCIBIO - Applied Molecular Biosciences Unit; DQ - Departamento de Química; Elsevier
The structural diversity of the lipopolysaccharides (LPSs) from Helicobacter pylori poses a challenge to establish accurate and strain-specific structure-function relationships in interactions with the host. Here, LPS structural domains from five clinical isolates were obtained and compared with the reference strain 26695. This was achieved combining information from structural analysis (GC-MS and ESI-MSn) with binding data after interrogation of a LPS-derived carbohydrate microarray with sequence-specific proteins. All LPSs expressed Lewisx/y and N-acetyllactosamine determinants. Ribans were also detected in LPSs from all clinical isolates, allowing their distinction from the 26695 LPS. There was evidence for 1,3-D-galactans and blood group H-type 2 sequences in two of the clinical isolates, the latter not yet described for H. pylori LPS. Furthermore, carbohydrate microarray analyses showed a strain-associated LPS recognition by the immune lectins DC-SIGN and galectin-3 and revealed distinctive LPS binding patterns by IgG antibodies in the serum from H. pylori-infected patients.
Determination of the chemical composition of Eucalyptus spp. For cellulosic pulp production
Publication . Vieira, Túlio Anselmo Sacramento; Arriel, Taiana Guimarães; Zanuncio, Antônio José Vinha; Carvalho, Amélia Guimarães; Branco-Vieira, Monique; Carabineiro, Sónia Alexandra Correia; Trugilho, Paulo Fernando; LAQV@REQUIMTE; DQ - Departamento de Química; MDPI - Multidisciplinary Digital Publishing Institute
The chemical composition of wood is important to assess the quality of this raw material for the industry of cellulosic pulp production. The purpose of this work was to determine the chemical composition of Eucalyptus spp. grown for cellulosic pulp production. Ten Eucalyptus spp. clones with six years of age, located in the municipality of Itamarandiba, Minas Gerais, Brazil, were used. Quantification was obtained for extractives, monosaccharides, uronic acids, acetates, lignin, ash and the phenolic composition of the extracts. In average, clones showed around 2.7% extractives, with a predominance of polar compounds soluble in ethanol and water; 27.7% lignin and 0.3% ash. Glucose was the main sugar detected (64.2%), followed by xylose (19.3%). The main components of the extractives were steroids, fatty acids and aromatic acids, followed by smaller amounts of substituted alkanoic acids, fatty alcohols, glycerol derivatives and triterpenes. The ethanol–water extracts presented total phenol contents ranging from 321.4 to 586.6 mg EAG/g of extract, tannins from 28.1 to 65.1 mg catechin/g of extract and flavonoids from 73.6 to 256.9 mg catechin/g of extract. Clones with a higher holocellulose amount and a lower lignin content showed a higher potential for cellulosic pulp production. These findings are important for the development of high-quality wood based on important traits for the pulp and paper sector.
Antineoplastic drugs in urban wastewater
Publication . Gouveia, Teresa I. A.; Cristóvão, Maria B.; Pereira, Vanessa J.; Crespo, João G.; Alves, Arminda; Ribeiro, Ana R.; Silva, Adrián; Santos, Mónica S. F.; LAQV@REQUIMTE; DQ - Departamento de Química; Instituto de Tecnologia Química e Biológica António Xavier (ITQB); Elsevier
Antineoplastic drugs are pharmaceuticals that have been raising concerns among the scientific community due to: (i) their increasing prescription in the fight against the disease of the twentieth century (cancer); (ii) their recalcitrance to conventional wastewater treatments; (iii) their poor environmental biodegradability; and (iv) their potential risk to any eukaryotic organism. This emerges the urgency in finding solutions to mitigate the entrance and accumulation of these hazardous chemicals in the environment. Advanced oxidation processes (AOPs) have been taken into consideration to improve the degradation of antineoplastic drugs in wastewater treatment plants (WWTPs), but the formation of by-products that are more toxic or exhibit a different toxicity profile than the parent drug is frequently reported. This work evaluates the performance of a nanofiltration pilot unit, equipped with a Desal 5DK membrane, in the treatment of real WWTP effluents contaminated (without spiking) with eleven pharmaceuticals, five of which were never studied before. Average removals of 68 ± 23% were achieved for the eleven compounds, with decreasing risks from feed to permeate for aquatic organisms from receiving waterbodies (with the exception of cyclophosphamide, for which a high risk was estimated in the permeate). Aditionally, no significative impact on the growth and germination of three different seeds (Lepidium sativum, Sinapis alba, and Sorghum saccharatum) were determined for permeate matrix in comparison to the control.
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Fundação para a Ciência e a Tecnologia
Programa de financiamento
6817 - DCRRNI ID
Número da atribuição
UIDB/00511/2020