18 documents found, page 1 of 2
Core-shell polymer aerogels prepared by co-polymerisation of 2,4-dihydroxybenzo...
Carrott, PJM; Marques, LM; Ribeiro Carrott, MMLDHBARF polymer aerogels were prepared from mixtures containing a fixed stoichiometric amount of formaldehyde (F) and varying proportions of resorcinol (R) and 2,4-dihydroxybenzoic acid (DHBA), with the objective of combining the advantages of high mesopore volume and solids content of RF aerogels with the ion exchange capacity of DHBAF aerogels. The results show that surface area, pore volume, pore size and ion...
Separating Surface and Solvent Effects and the Notion of Critical Adsorption En...
Carrott, PJM; Mourão, PAM; Ribeiro Carrott, MML; Gonçalves, EMA modified form of the Freundlich equation in which the solute equilibrium concentration is normalized with respect to the solute solubility is analyzed and applied to adsorption isotherms of phenol, 4-nitrophenol, 4-chlorophenol, and 2-chlorophenol at different values of pH on commercial activated carbon before and after oxidation. The analysis confirms the importance of normalizing the solute equilibrium conc...
Low-Cost Adsorbents: Growing Approach to Wastewater Treatment—a Review
Gupta, VK; Carrott, PJM; Ribeiro Carrott, MML; SuhasIndustrial, agricultural, and domestic activities of humans have affected the environmental system, resulting in drastic problems such as global warming and the generation of wastewater containing high levels of pollutants. As water of good quality is a precious commodity and available in limited amounts, it has become highly imperative to treat wastewater for removal of pollutants. In addition, the rapid moder...
New carbon materials with high porosity in the 1–7 nm range obtained by chemica...
Conceição, FL; Carrott, PJM; Ribeiro Carrott, MMLChemical activation of resorcinol–formaldehyde aerogels with phosphoric acid results in materials containing both intra-particle microporosity (pore volume ˇ0.18 cm3g 1 and mean-pore-width ˇ1 nm) and inter-particle micro/mesoporosity. The latter forms as a result of partial collapse of the mesopore structure of the organic aerogel and can be controlled by varying the phosphoric acid/organic aerogel ratio. Incre...
Using alkali metals to control reactivity and porosity during physical activati...
Suhas; Carrott, PJM; Ribeiro Carrott, MMLDemineralised kraft lignin was impregnated with between 6.2% and 50% NaCl or KCl and physically activated in CO2 at 750 C. The results presented show that a considerable reduction in activation time even at a comparatively low activation temperature could be achieved, particularly when using KCl. Considering a fixed level of burn-off, the impregnation did not affect the pore volume and only increased the pore w...
Influence of thermal treatment conditions on porosity development and mechanica...
Ramos, ME; Bonelli, PR; Cuckierman, AL; Ribeiro Carrott, MML; Carrott, PJMActivated carbon cloths (ACC)were prepared fromTencel®, a novel regenerated cellulose nanofibre fabric, by phosphoric acid activation in an inert atmosphere using different thermal treatment conditions. The effect of the final thermal treatment temperature (663–963 ◦C) and temperature programme (temperature of isothermal step and heating rate) on yield, elemental composition, porosity development and mechanical...
Characterisation by adsorption of various organic vapours of the porosity of fr...
Russo, PA; Ribeiro Carrott, MML; Carrott, PJM; Matias, P; Lopes, JM; Guisnet, M; Ramôa Ribeiro, FThe microporosity of H-MCM-22 samples, fresh and deactivated by coke during methylcyclohexane transformation at 350 C for 10 h, was characterised by adsorption of nitrogen and organic molecules of different size, namely, p- and o-xylenes, mesitylene and methylcyclohexane. Nitrogen adsorption was also carried out on the fresh sample after pre-adsorption of the hydrocarbons. All of these can fit the outer 12 MR c...
Adsorption Properties of Activated Carbons Prepared from Recycled PET in the Re...
Cansado, IPP; Galacho, Cristina; Nunes, AS; Ribeiro Carrott, MML; Carrott, PJMActivated carbons (ACs) were prepared from recycled polyethylene terephthalate (PET) by chemical activation with KOH and used successfully for the removal of 4-chloro-2-methylphenoxyacetic acid (MCPA) and Methylene Blue (MB) from aqueous media. In order to improve the adsorption capacity towards pollutant removal, the AC was submitted to different post-treatments. After oxidation, the sample exhibited an increa...
Adsorption of Bovine Serum Albumin onto Mesocellular Silica Foams with Differen...
Sezões, F; Ribeiro Carrott, MML; Mourão, PAM; Carrott, PJMAs a model protein with quite large dimensions, Bovine Serum Albumin (BSA) has been used to evaluate the influence of the distinct pore structural characteristics of three mesocellular foam (MCF) materials prepared with or without the addition of ammonium fluoride and with varying 1,3,5-trimethylbenzene/Pluronic P123 (TMB/P123) ratios. SBA-15 was also studied for comparative purposes. Characterisation by X-ray ...
Competitive naphthalene adsorption on activated carbons. Effect of porosity and...
Cabal, B; Ania, CO; Mourão, PAM; Ribeiro Carrott, MML; Carrott, PJM; Parra, JB; Pis, JJThe goal of this work was to investigate the mechanism of competitive adsorption of naphthalene on activated carbons from diluted solutions. The polarity of the adsorption media was varied, by selecting solvents ranging from high to low dielectric constants (ethanol, cyclohexane and heptane). By altering the hydrophobicity of the adsorption media, the preferential adsorption of the organic probe is changed; the...