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Multicomponent adsorption of pentavalent As, Sb and P onto iron-coated cork gra...
Ariana M. A. Pintor; Cátia C. Brandão; Rui A. R. Boaventura; Cidália M. S. BotelhoThe assessment of multicomponent adsorption of pentavalent metalloids is important since they are often found together in groundwaters and mining runoff. For this purpose, adsorption of As(V), Sb(V) and P(V) onto ironcoated cork granulates was studied in binary and ternary systems. Data from equilibrium and kinetic studies revealed that uptake of these contaminants is a multilayer, heterogeneous process well de...
Arsenic removal from water using iron-coated seaweeds
Bárbara R. C. Vieira; Ariana M. A. Pintor; Rui A. R. Boaventura; Cidália M. S. Botelho; Sílvia C. R. SantosArsenic is a semi-metal element that can enter in water bodies and drinking water supplies from natural deposits and from mining, industrial and agricultural practices. The aim of the present work was to propose an alternative process for removing As from water, based on adsorption on a brown seaweed (Sargassum muticum), after a simple and inexpensive treatment: coating with iron-oxy (hydroxides). Adsorption eq...
Tannin-based biosorbents for environmental applications - A review
Hugo A. M. Bacelo; Sílvia C. R. Santos; Cidália M. S. BotelhoAdsorption has been proved as an efficient process to remove a multiplicity of solutes from aqueous solution. Various biosorbents have found promising applications in wastewater treatment and in the recovery of critical metals that is, nowadays, the spotlight due to the promotion of environmental and economic sustainability. Tannins are excellent candidates to produce biosorbents. These ubiquitous and inexpensi...
Antimony oxyanions uptake by green marine macroalgae
Gabriela Ungureanu; Catalina Filote; Sílvia C. R. Santos; Rui A. R. Boaventura; Irina Volf; Cidália M. S. BotelhoThe potential of green seaweeds, Cladophora sericea and Ulva rigida, to adsorb antimony(III) and antimony (V) from aqueous solution was studied in batch mode. The hydroxyl and carboxyl groups from the algae surface, responsible for Sb uptake, were quantified by potentiometric titration and a continuous model for the deprotonation of these sites was obtained. Kinetic studies using C. sericea as biosorbent were c...
Treatment of vegetable oil refinery wastewater by sorption of oil and grease on...
Ariana M. A. Pintor; Andreia G.Martins; Renata S. Souza; Vítor J. P. Vilar; Cidália M. S. Botelho; Rui A. R. BoaventuraThe feasibility of a novel sorption treatment using regranulated cork granules for oil and grease (O&G) removal from real vegetable oil refinery wastewaters (VORW) was investigated and compared to similar treatment of oil-in-water emulsions. O&G sorption from real VORW onto regranulated cork particles was studied at different pH and ionic strength conditions. Only wastewater acidification was able to effectivel...
The role of emulsion properties and stability in vegetable oil uptake by regran...
Ariana M. A. Pintor; Renata S. Souza; Vítor J. P. Vilar; Cidália M. S. Botelho; Rui A. R. BoaventuraBACKGROUNDThis work presents a novel approach to the understanding of electrostatic phenomena and sorbate-sorbent interactions in oil sorption. The study focuses on sorption of sunflower oil onto regranulated cork granules as promising natural sorbents. RESULTSIt was shown that lowering the pH caused neutralization of negative surface charge by the positive hydrogen ions, leading to a reduction in the negative ...
Oil desorption and recovery from cork sorbents
Ariana M. A. Pintor; Catarina I. A. Ferreira; Joana P. C. Pereira; Renata S. Souza; Susana P. Silva; Vítor J. P. Vilar; Cidália M. S. BotelhoThis study focuses on the recovery of sunflower oil from cork sorbents, namely of regranulated type, either by desorption using different eluents or by mechanical compression. Saturation of sorbents was carried out in pure oil medium. Elution with tap water, 0.1 M H2SO4 and 10 mM sodium dodecyl sulphate (SDS, anionic surfactant) solutions showed very low efficiency, below 10%. Slight improvement was achieved wi...
Performance evaluation of the main units of a refinery wastewater treatment pla...
Carlos E. Santo; André Fonseca; Eva Kumar; Amit Bhatnagar; Vítor J. P. Vilar; Cidália M. S. Botelho; Rui A. R. BoaventuraPetroleum refineries generate great amounts of wastewaters which require proper treatment before being discharged into coastal waters or other aquatic systems. The main pollutants present in these industrial wastewaters include suspended particles, biodegradable and refractory organics, hydrocarbons, sulfides, phenols and nitrogen compounds. The performance of the Porto Refinery wastewater treatment plant (WWTP...
Optimization of a primary gravity separation treatment for vegetable oil refine...
Ariana M. A. Pintor; Vítor J. P. Vilar; Cidália M. S. Botelho; Rui A. R. BoaventuraVegetable oil refinery wastewaters (VORW) are loaded with organic and oily matter, and cannot be decontaminated by conventional treatment methods. Pretreatment methods with the objective of decreasing oil and grease (O&G) and chemical oxygen demand (COD) content either generate hazardous byproducts or may be too costly. In this paper, it is demonstrated that gravity separation is appropriate as a low-cost prima...
Integrated reduction/oxidation reactions and sorption processes for Cr(VI) remo...
Ingrid M. Dittert; Heloisa de Lima Brandão; Eduardo A. B. da Silva; Selene M. A. Guelli U. de Souza; Antônio Augusto U. de Souza; Cidália M. S. BotelhoThe main goal of this work was the valorization of seaweed Laminaria digitata, after acid pre-treatment, for the remediation of hexavalent chromium solutions. The Cr(VI) removal efficiency by the protonated biomass was studied as a function of different parameters, such as contact time, pH, biomass and Cr(VI) concentration, and temperature. Cr(VI) removal is based on a complex mechanism that includes a reductio...