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Vermiculite as a potential functional additive for water treatment bioreactors ...
Węgrzyn, Agnieszka; Tsurtsumia, Avtandil; Witkowski, Stefan; Freitas, Olga; Figueiredo, Sónia; Cybińska, Joanna; Stawiński, WojciechA new adsorbent that combines mineral vermiculite with the yeast Saccharomyces cerevisiae, was used for Cd2+ removal. The influence of vermiculite presence on the toxic effects of Cd2+ to Saccharomyces cerevisiae yeast was evaluated as a function of the microorganisms' respiratory activity (CO2 production). The Cd2+ toxicity increased with prolonged exposure time reaching the LC50 value of 857 and 489 mg L−1 af...
Adsorption of Fluoxetine and Venlafaxine onto the Marine Seaweed Bifurcaria bif...
Silva, Andreia; Stawiński, Wojciech; Romacho, Juan; Santos, Lúcia H.M.L.M.; Figueiredo, Sónia; Freitas, Olga; Delerue-Matos, CristinaMarine macroalga Bifurcaria bifurcata was investigated as sorbent for two environmental emerging pollutants, the pharmaceuticals venlafaxine (VLF) and fluoxetine (FLX), from aqueous solutions, both in mono and bicomponent batch systems. The alga was characterized by means of IR spectroscopy, allowing to identify the most important groups for biosorption, carboxylic, sulfonic and hidroxile. The point of zero cha...
Interaction between adsorbed molecules and tailor made large chelating ligands ...
Węgrzyn, Agnieszka; Radko, Marcelina; Majda, Dorota; Stawiński, Wojciech; Skiba, Michał; Cież, DariuszModified mesoporous silicas were examined as adsorbents for efficient removal of model pollutants from wastewaters. Functionalized SBA-15 materials for capture of cationic pollutants such as metal cations and anionic dyes were obtained using post-synthesis grafting method. Large organic ligands containing acetyloacetone, 2-aminopyridine, 2-aminothiazole and 2-aminobenzothiazole groups were incorporated into the...
Sustainable adsorbents formed from by-product of acid activation of vermiculite...
Stawiński, Wojciech; Węgrzyn, Agnieszka; Mordarski, Grzegorz; Skiba, Michał; Freitas, Olga; Figueiredo, SóniaHydrotalcite-like layered double hydroxide (LDH) materials were synthesized from liquid waste by-product produced during acid activation of vermiculite (raw (W) and expanded (Ve)), and by combining the waste with the activated mineral, novel hybrid vermiculite-hydrotalcite-like materials were obtained in one-pot synthesis. Batch system adsorption experiments were performed on fresh and calcined (at 450 °C) mate...
Study of adsorptive materials obtained by wet fine milling and acid activation ...
Węgrzyn, Agnieszka; Stawiński, Wojciech; Freitas, Olga; Komędera, Kamila; Błachowski, Artur; Jęczmionek, Łukasz; Dańko, Tomasz; Mordarski, GrzegorzWet fine milling, as a pretreatment step to acid activation of vermiculite, was applied in order to decrease the environmental impact of the procedure commonly used to increase the mineral's adsorption capacity. Milling caused fragmentation of the material and several changes in its structure: edges of the flocks became frayed, the surface cracked, cation exchange capacity (CEC) increased, and most of the iron ...
Application of vermiculite-derived sustainable adsorbents for removal of venlaf...
Silva, Andreia; Martinho, Sílvia; Stawiński, Wojciech; Węgrzyn, Agnieszka; Figueiredo, Sónia; Santos, Lúcia H. M. L. M.; Freitas, OlgaRemoval of emerging pollutants, such as pharmaceuticals, from wastewater is a challenge. Adsorption is a simple and efficient process that can be applied. Clays, which are natural and low-cost materials, have been investigated as adsorbent. In this work, raw vermiculite and its three modified forms (expanded, base, and acid/base treated) were tested for removal of a widely used antidepressant, venlafaxine. Adso...
Acid-base treated vermiculite as high performance adsorbent: Insights into the ...
Stawiński, Wojciech; Węgrzyn, Agnieszka; Dańko, Tomasz; Freitas, Olga; Figueiredo, Sónia; Chmielarz, LucjanAdditional treatment with NaOH of acid activated vermiculite results in even higher increase in the adsorption capacity in comparison to samples modified only in acidic solution (first step of activation) with respect to raw material. Optimization of treatment conditions and adsorption capacity for two cationic dyes (methylene blue (MB) and astrazon red (AR)), also as binary mixture, was evaluated. The capacity...
Dual-function hydrotalcite-derived adsorbents with sulfur storage properties: D...
Stawiński, Wojciech; Węgrzyn, Agnieszka; Freitas, Olga; Chmielarz, Lucjan; Figueiredo, SóniaThermal treatment of hydrotalcite at increasing temperatures resulted in formation of mixed oxides that exhibited different adsorption behavior toward anionic and cationic industrial dyes. The material annealed at 450 °C was characterized by the highest maximum adsorption capacity for both types of dyes. The adsorption was strongly pH dependent and for the anionic dye abatement low pH was favored whilst higher ...
The influence of acid treatments over vermiculite based material as adsorbent f...
Stawiński, Wojciech; Freitas, Olga; Chmielarz, Lucjan; Węgrzyn, Agnieszka; Komędera, Kamila; Błachowski, Artur; Figueiredo, SóniaThe influence of different acid treatments over vermiculite was evaluated. Equilibrium, kinetic and column studies have been conducted. The results showed that vermiculite first treated with nitric acid and then with citric acid has higher adsorption capacity, presenting maximum adsorption capacities in column experiments: for Astrazon Red (AR), 100.8 ± 0.8 mg g−1 and 54 ± 1 mg g−1 for modified and raw material...
Simultaneous removal of dyes and metal cations using an acid, acid-base and bas...
Stawiński, Wojciech; Węgrzyn, Agnieszka; Freitas, Olga; Chmielarz, Lucjan; Mordarski, Grzegorz; Figueiredo, SóniaThe aimof thiswork was the modification of vermiculite in order to produce a lowcost, efficient and sustainable adsorbent for dyes and metals. Three activation methods consisting of acid, base and combined acid/base treatment were applied to improve the of vermiculite's adsorption properties. Adsorbents were tested in single, biand tricomponent solutions containing cationic dyes and Cu2+ cations. The rawmateria...