Camila Baldasso

Performance of rotary kiln reactor for the elephant grass pyrolysis.

The influence of process conditions (rotary speed/temperature) on the performance of a rotary kiln reactor for non-catalytic pyrolysis of a perennial grass (elephant grass) was investigated. The product yields, the production of non-condensable gases as well as the biochar properties were evaluated. The maximum H2 yield was close to that observed for catalytic pyrolysis processes, while the bio-oil yield was higher than reported for pyrolysis of other biomass in rotary kiln reactors. A H2/CO ratio suitable for Fischer-Tropsch synthesis (FTS) was obtained. The biochars presented an alkaline pH (above 10) and interesting contents of nutrients, as well as low electrical conductivity, indicating a high potential as soil amendment.

Whey fractionation through the membrane separation process

ABSTRACT The aim of this work is to improve the utilisation of fractions of whey through membrane separation processes. From a solution of whey treated by ultrafiltration (UF) associated with diafiltration (DF), two streams were obtained: a concentrate and a permeate. In this process, a purified protein concentrate with about 70% of protein was obtained. Permeate was treated by electrodialysis (ED) to obtain a fraction rich in lactose (90%). The final effluent was treated by reverse osmosis (RO) in order to recover water free of salts. RO made it possible to recover 50% water and retain 85% of the salts.

Production and characterization of poly(3-hydroxybutyrate) generated by Alcaligenes latus using lactose and whey after acid protein precipitation process.

Whey after acid protein precipitation was used as substrate for PHB production in orbital shaker using Alcaligenes latus. Statistical analysis determined the most appropriate hydroxide for pH neutralization of whey after protein precipitation among NH4OH, KOH and NaOH 10%w/v. The results were compared to those of commercial lactose. A scale-up test in a 4L bioreactor was done at 35°C, 750rpm, 7L/min air flow, and 6.5 pH. The PHB was characterized through Fourier Transform Infrared Spectroscopy, thermogravimetry and differential scanning calorimetry. NH4OH provided the best results for productivity (p), 0.11g/L.h, and for polymer yield, (YP/S), 1.08g/g. The bioreactor experiment resulted in lower p and YP/S. PHB showed maximum degradation temperature (291°C), melting temperature (169°C), and chemical properties similar to those of standard PHB. The use of whey as a substrate for PHB production did not affect significantly the final product quality.

Aerogel preparation from short cellulose nanofiber of the Eucalyptus species

Wood is the main industrial source for obtaining cellulose. It is a natural composite, constituted by cellulose, polyoses, lignin, small amounts of extracts and mineral salts, wherein cellulose is the most abundant component. Many studies are being developed for obtaining materials based on natural fibers, which combine interesting properties such as renewability, biodegradability, low density and low cost. Aerogels are solid, lightweight materials with high porosity and high internal surface area. These features combined in one single material make the aerogels a differentiated product with potential for use as an adsorbent. In this context, aerogels made of cellulose nanofibers obtained from short-fiber cellulose of Eucalyptus sp. were made. The cellulose suspension was first disintegrated by a mechanical grinder, and the aerogels were undergone to freeze-drying. The characterization of the samples was performed by apparent density, porosity, scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analyses. According to the micrographs obtained by scanning electron microscopy and field emission gun scanning electron microscopy, it was observed the formation of pores formed by the interconnection of cellulose fibers. The apparent density of the starting cellulose fibers (pressed plates) was 0.6998 g.cm−3 and the aerogel density decreased to 0.0240 g.cm−3. The values for aerogel porosity were about 97%, which benefits the passage of liquids and gases from the external environment to the internal structure of the material. Fourier transform infrared spectroscopy and thermogravimetric analyses showed no change in the chemical composition or in the thermal stability of the obtained aerogels in comparison to their starting materials.

Sorption capacity of hydrophobic cellulose cryogels silanized by two different methods

The production of cellulose cryogels for petroleum sorption is a relevant study since cellulose is an economical, renewable, biodegradable and abundant source in the environment. However, as this material is of hydrophilic character it is necessary to modify the hydrophobicity of the cellulose fiber surfaces by using organosilanes, for example. The aim of this work is the development of hydrophobic cellulose cryogels for application in petroleum sorption. For this, was compared the sorption capacity of cryogels silanized by methyltrimethoxysilane (MTMS) through two methods: vapor deposition and addition of silane to cellulose suspension. For the samples with MTMS addition to the cellulose suspension, modifying the MTMS fiber surfaces increased the water contact angle on average by 112°. For the samples modifyed by vapor deposition the increase was of 119°. The most effective silanization method was by vapor deposition where the petroleum sorption capacity was 50% higher than by the cellulose addition method.

Cornstarch-Gelatin Films: Commercial Gelatin Versus Chromed Leather Waste Gelatin and Evaluation of Drying Conditions

In this work, gelatin extracted from chromed leather waste (CLW) was used with cornstarch and glycerol to produce polymeric films. These films were compared with commercial gelatin ones. Gelatin from CLW presented a more pronounced plasticizer behavior than commercial gelatin. It may have occurred due to its lower molar mass, due to the presence of free amino acids from the partial degradation of the protein polypeptide chain during CLW gelatin extraction, and/or due to the presence of high salts content. The high drying temperature (40 °C) made the drying process faster than the starch retrogradation process. It resulted in the reduction of films crystallinity and tensile strength, and in the increase of elongation at break. It also increased equilibrium moisture content, as indicated by water sorption isotherms. FTIR spectra indicated that the absorption bands of cornstarch and CLW gelatin films are the same ones found for films of these materials when not combined, which indicates the presence of a system with phase separation.

Obtaining Hydrophobic Aerogels of Unbleached Cellulose Nanofibers of the Species Eucalyptus sp. and Pinus elliottii

The use of natural fibers from renewable and biodegradable sources in oleophilic sorbents, such as cellulose, has become an interesting alternative due to their excellent properties and sustainability. In addition to that, the low density of the aerogels obtained from cellulose is favorable for their use as sorbents. In this context, the objective of this study is to develop hydrophobic aerogels of unbleached cellulose nanofibers of the Eucalyptus sp. and Pinus elliottii. Cellulose samples were submitted to mechanical fibrillation to obtain cellulose nanofiber suspensions, followed by a chemical treatment with methyltrimethoxysilane and dried by freeze-drying to prepare the aerogels. The aerogels presented hydrophobic and oleophilic characteristics, including a water contact angle of 134°, sorption capacities in a heterogeneous medium of above 21.0 g·g−1, and oil removal efficiency greater than 88.5%. The Pinus elliottii nanofiber aerogels showed higher compressive strength when compared to the nanofiber aerogels of Eucalyptus sp.