Aline Dettmer

Nanofibrillated cellulose from tobacco industry wastes.

Tobacco stems waste underwent steam explosion pulping for nanofibrillated cellulose (NFC) production. In order to obtain NFC hydrogels, the pulp obtained by steam explosion was bleached and refined in a grinder employing specific energy of up to 5067kWh/t. Eucalyptus kraft pulp was processed under the same conditions to produce NFC hydrogels, later used in order to compare with NFC hydrogels from tobacco stems waste. According to statistical analysis, the optimum tobacco stems pulping condition was obtained with a severity index of log3.0 and active alkali of 16.25%. These conditions allowed obtaining a bleached pulp with Schopper Riegler degree of 46. Electronic microscopy with field emission showed a higher presence of nanofibers in the tobacco stems pulp than in commercial eucalyptus kraft pulp, both after refining. Thermal analysis indicated that tobacco stems pulp degrade at lower temperatures than eucalyptus kraft pulp. FTIR analysis did not indicate chemical bonding differences between the two pulps.

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.

Evaluation of the degradation of HDPE hybrid composites using wood flour from CCA-treated poles, and recycled ceramic insulators

Waste from the maintenance of electricity distribution networks is generated every day, in repairing and replacement of components used in electricity distribution networks. Among the most dangerous residues, wood poles treated with chromated copper arsenate are distinguished by the toxicity of the chemical treatment it has been submitted to, as well as its ceramic insulators, due to the difficult recyclability of this material. Thus, an alternative may be the reuse of these components as reinforcing elements in polymeric composites. Based on this, two residues were used as fillers for the production of high-density polyethylene (HDPE) hybrid composites, wood powder, and insulating ceramic powder. Degradation by ultraviolet (UV) exposure in controlled environments of the composites was also evaluated, and toxicity tests were carried out based on the leaching of these loads with increased exposure time to degradation. Composites presented higher tensile and flexural properties than pure HDPE, and after the exposure to the UV degradation process, the composites presented fewer cracks when compared to HDPE. After exposure to the simulated degradation environment, the levels of chromium, copper, and arsenic leached were within the limits allowed by the standard that provides classification and means of disposal of these materials.

Characteristics of Pyrolysis Products from Waste Tyres and Spent Foundry Sand Co-Pyrolysis

The products obtained through thermal conversion of tyres can represent a solution for its disposal which has been considered an environmental problem. In the foundry industry two types of sand are generated: core sand (CS) and green sand (GS); CS is classified as hazardous waste. In this paper two kinds of industrial wastes were approached, in order to propose a solution through co-pyrolysis. The experiments were performed in a bubbling fluidized bed reactor. The oil, fuel gas and char obtained were characterized. The main components present in the oil were naphthalene and anthracene. Char morphology was assessed by Scanning Electron Microscopy, confirming the resin absence on its surface. Isothermal adsorption and desorption indicated that the char obtained from tyre pyrolysis with lower particles has higher superficial area (higher than 200 m2·g−1). The main compounds identified in fuel gas were hydrogen, carbon monoxide, carbon dioxide and hydrocarbons up to 5 carbons.