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Cordeiro, T, Paninho AB, Bernardo M, Matos I, Pereira CV, Serra AT, Matias A, Ventura MG.  2020.  Biocompatible locust bean gum as mesoporous carriers for naproxen delivery. Materials Chemistry and Physics. 239:121973. AbstractWebsite

The work reports the impregnation of naproxen into locust bean gum mesoporous matrixes with different textural properties. The matrixes were prepared through the dissolution of the biopolymer in water and in two ionic liquids (ILs): [bmim][Cl] and [C2OHmim][Cl] and dried with scCO2. The poor water-soluble pharmaceutical drug naproxen was loaded into the matrixes and the composites were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy and by differential scanning calorimetry; the results were compared with neat ILs and drug. The naproxen release from the matrixes was attempted at pH 7.4. Sustained release of naproxen in the different composites occurs, and consequently the naproxen release has lower rates compared with neat crystalline naproxen dissolution. Nevertheless, it was possible to observe small differences on release profiles for the studied composites. The higher release rate was observed for the composite where [bmim][Cl] was used as solvent, for which the calorimetric analysis revealed full amorphization of the incorporated drug. Cytotoxicity assays reveal that cellular viability in Caco-2 cells is preserved. This fact allied with the biocompatibility of locust bean gum allow for the composites potential application as naproxen controlled/sustained delivery systems with higher drug bioavailability achieved through naproxen amorphization.

Batista, MKS, Mestre AS, Matos I, Fonseca IM, Carvalho AP.  2016.  Biodiesel production waste as promising biomass precursor of reusable activated carbons for caffeine removal. RSC Adv.. 6:45419-45427.: The Royal Society of Chemistry AbstractWebsite

Biodiesel production generates low particle size rapeseed waste (recovered from warehouse air filtration systems) that was herein explored as promising biomass precursor of chemically activated carbons. The influence of several experimental parameters on the porosity development was investigated. No benefit was observed when solution impregnation was made nor a significant dependence of the biomass : K2CO3 ratio was observed and{,} as expected{,} high porosity development was obtained only for treatments at 700 [degree]C. Microporous materials with apparent surface area around 1000 m2 g-1 were obtained comparing favorably with literature data regarding activated carbons from rapeseed processing by-products. A selected lab-made sample and two commercial carbons were tested as adsorbents of caffeine from aqueous solution. Although commercial materials present a quicker adsorption rate{,} regarding adsorption capacity the lab-made sample reaches the same value attained by a benchmark material. The regeneration tests made over the rapeseed derived carbon through heat treatments at 600 [degree]C for 1 hour under N2 flow proved that at least two exhaustion-regeneration cycles can be made since the material retains a caffeine adsorption capacity similar to that of the fresh carbon. Therefore{,} a waste management problem of biodiesel industry - rapeseed residue - can be transformed in a valuable material with promising properties for environmental remediation processes.

do Fraga, AC, Quitete CPB, Ximenes VL, Sousa-Aguiar EF, Fonseca IM, Rego AMB.  2016.  Biomass derived solid acids as effective hydrolysis catalysts. Journal of Molecular Catalysis A: Chemical. 422:248-257. AbstractWebsite

The conversion of cellulose into products with higher added value often includes a depolymerization step to obtain glucose, its fundamental unity. The depolymerization reaction is carried out via hydrolysis of the β-1,4-glycosidic bond. The search for a solid acid catalyst capable of breaking these bonds is gaining increasing prominence in the literature. In this regard, sulfonated carbons have shown promising results. This work evaluated the use of a residue from the extraction of palm oil as raw material for the production of sulfonated carbons. The raw material was carbonized and sulfonated. The obtained solid acids were tested in the hydrolysis of cellobiose, a dimer of glucose often used as a model compound for cellulose. The hydrolysis reaction is the first step in converting renewable carbon sources into chemical products and biofuels. Some aspects were investigated, as the effect of carbonization temperature on the concentration of sulfonic groups, the results showing that the content thereof reached a maximum value at 300°C. Regarding the hydrolysis of cellobiose, it has been identified that there is a relationship between the concentration of sulfonic acid groups and the activity of these catalysts. However, there is a drop in the turnover number as the amount of sulfonic acid sites increases. This was related to a preferred position sulfonation mechanism. Furthermore, sulfonated carbons showed higher activity than the commercial acid resins, indicating that this material may be a good option for the generation of solid acid catalysts.

Surra, E, Bernardo M, Lapa N, Esteves IAAC, Fonseca I, Mota JPB.  2019.  Biomethane production through anaerobic co-digestion with Maize Cob Waste based on a biorefinery concept: A review. Journal of Environmental Management. 249:109351. AbstractWebsite

Maize Cob Waste (MCW) is available worldwide in high amounts, as maize is the most produced cereal in the world. MCW is generally left in the crop fields, but due to its low biodegradability it has a negligible impact in soil fertility. Moreover, MCW can be used as substrate to balance the C/N ratio during the Anaerobic co-Digestion (AcoD) with other biodegradable substrates, and is an excellent precursor for the production of Activated Carbons (ACs). In this context, a biorefinery is theoretically discussed in the present review, based on the idea that MCW, after proper pre-treatment is valorised as precursor of ACs and as co-substrate in AcoD for biomethane generation. This paper provides an overview on different scientific and technological aspects that can be involved in the development of the proposed biorefinery; the major topics considered in this work are the following ones: (i) the most suitable pre-treatments of MCW prior to AcoD; (ii) AcoD process with regard to the critical parameters resulting from MCW pre-treatments; (iii) production of ACs using MCW as precursor, with the aim to use these ACs in biogas conditioning (H2S removal) and upgrading (biomethane production), and (iv) an overview on biogas upgrading technologies.