Implicancias ambientales de la deslignificación de pulpas kraft de eucalipto utilizando perácidos

Because of great environmental pressures, the cellulose industry has studied the potential of use of new bleaching agents among which peroxymonosulfuric acid and peracetic acid stand out. This survey summarizes the results of various laboratory investigations using peracids to delignify eucalyptus kraft pulps. The effect of a step using peroxymonosulfuric acid followed by a D-Eo-D sequence [free of elemental chlorine] was studied and compared with the use of peracetic acid and mixtures of these two acids. It was shown that a mixture of peroxymonosulfuric acid and peracetic acid reduced more lignin (measured as kappa index) than the individual peracids, and reduced more hexenuronic acid than peracetic acid with less degradation of the cellulose than with peroxymonosulfuric acid. This was explained on the basis of the electrophilic and nucleophilic properties of these acids that improved the delignification of eucalyptus kraft pulp. The effluents generated in these steps involving the peracids had greater color, chemical oxygen demand (COD), and total phenols correlating with the amount of lignin removed and the analyses of bioassays did not show acute toxicity from effluents coming from a peroxymonosulfuric acid step. The delignification with peracids may possibly reduce the use of chlorine dioxide in a sequence involving bleaching with elemental free chlorine (ECF), in this way reducing the concentration of organic chlorides (AOX) in the bleaching effluent

Natural fibre insulation in rural southern Chile

Thermal insulation is probably one of the most important elements in reducing the heating demands of residential accommodation in a cool temperate climate. However many insulating materials have a large environmental impact and high embodied energy. Research has shown that natural fibres can provide insulation with a lower impact especially when sourced locally. This paper presents a study of the natural fibres with insulating potential available in the micro-region of Araucania Andina in Chile’s 9th Region, a temperate region with long cold wet winters and short hot summers. An environmental impact matrix is used to select the materials with the lowest impact, which in turn are subjected to laboratory guarded hot box testing to determine their thermal conductivity. The final results will inform the design of a sustainable construction system for the micro-region. Materials evaluated include cellulose fibre from the forestry industry which is one of the principal sectors in the local economy; straw bales from wheat production, Chile’s main agricultural crop of which the region is the second largest national producer; sheep’s wool from the region and those further to the south; and two different local species of bamboo, colihue which currently has limited use for furniture and internal finishes and the highly invasive quila which requires constant clearing to reduce the threat of forest fires yet has no current commercial value. Results show that sheep’s wool provides the best insulation values, followed by straw bale and interesting that chipped quila bamboo could provide an economic natural insulation with low environmental impacts

Chusquea quila, a Natural Resource from Chile: Its Chemical, Physical, and Nanomechanical Properties

Chusquea quila or 'quila', is one of the most abundant lesser-known species from Chile, and for many years it has created problems for farmers in the southern part of this country. In this study, it was examined as a promising resource for high-tech materials. The chemical and physical properties were determined by ASTM standards. The extractives, ash content, lignin, and alpha-cellulose were 4.55%, 2.17%, 13.78%, and 54.65%, respectively. The higher heating value and basic density obtained were 5,106 kcal/kg and 290 kg/m(3), respectively. The moisture content was studied during four seasons and found to be the highest in winter (73%). Regarding the nanomechanical profiles, hardness varied from 0.16 GPa in the cortex to 0.21 GPa in the nodule. The average elastic modulus in the nodule and internode was 12.5 GPa, while in the cortex it was 7.45 GPa. Considering the high cellulose content and structural features of the lignocellulosic matrix, it could be possible to extract cellulose fibers for commercial use and crude lignin for testing new applications. Thus, the entire quila structure is a potential biomass resource

TREATMENT OF PULP MILL WASTEWATERS WITH Fusarium solani IN A ROTATING BIOLOGICAL CONTACTOR

This study assesses the feasibility of using the filamentous fungus Fusarium solani for the removal of colour, chemical oxygen demand (COD) and total phenols from a pulp mill industry effluent, inoculated in a rotating biological contactor (RBC). The study was done in a RBC of total volume 7.2 L, operated with 40% of useful volume at 37(+/- 2)degrees C, inflow 3.5 L d(-1), hydraulic residence time (HRT) 20 h and rotation speed 2 rpm. A Haldane model was used to determine the kinetic parameters of F. solani with a model effluent. The results show maximum elimination capacities and removal efficiencies for COD and phenols of 2921 mg m(-2) d(-1) (84%) and 72 mg m(-2) d(-1) (83%), respectively. Colour removal efficiencies of 60% (equivalent to 32 colour units, CU) were also obtained. The kinetic results show COD inhibition at concentrations above 110 mg L-1

Exploring an oxidative bleaching treatment for Chilean bamboo: a source of cellulose for biofuel generation and the nanotech industry

Quila (Chusquea quila) is a very abundant native Chilean bamboo species. This work reports on a delignification process which can be applied to quila to produce crystalline cellulose, an important resource for obtaining cellulose nanofibres or nanocrystals. Alternatively, the crystalline cellulose can then be subjected to fermentation processes, making it a useful raw material for biofuel production. The treatment studied is an oxidative treatment at low concentration (15% v/v), for short time periods (10, 20 min) and at temperatures between 100 and 140 degrees C, which produces alpha-cellulose fibres with high crystallinity (over 70%) and low residual lignin content (< 2%). The morphology of the cellulose fibres was analysed by scanning electron microscope, revealing a smooth surface containing many fibrils. Infrared spectroscopy was used to identify functional groups, showing that almost 99% of the lignin was removed. The crystallinity index of the cellulose fibres after the reaction was up to 79%, making it an excellent raw material for processing cellulose nanofibres required by the emerging nanotech industry. Carbohydrate analysis revealed 86% glucose and 14% xylose, which makes quila a promising candidate as a precursor for biofuel generati

Chusquea quila, a Natural Resource from Chile

Chusquea quila or "quila", is one of the most abundant lesser-known species from Chile, and for many years it has created problems for farmers in the southern part of this country. In this study, it was examined as a promising resource for high-tech materials. The chemical and physical properties were determined by ASTM standards. The extractives, ash content, lignin, and alpha-cellulose were 4.55%, 2.17%, 13.78%, and 54.65%, respectively. The higher heating value and basic density obtained were 5,106 kcal/kg and 290 kg/m(3), respectively. The moisture content was studied during four seasons and found to be the highest in winter (73%). Regarding the nanomechanical profiles, hardness varied from 0.16 GPa in the cortex to 0.21 GPa in the nodule. The average elastic modulus in the nodule and internode was 12.5 GPa, while in the cortex it was 7.45 GPa. Considering the high cellulose content and structural features of the lignocellulosic matrix, it could be possible to extract cellulose fibers for commercial use and crude lignin for testing new applications. Thus, the entire quila structure is a potential biomass resource.Peer reviewe

Effects of Temperature on Steam Explosion Pretreatment of Poplar Hybrids with Different Lignin Contents in Bioethanol Production

The aim of this study is to evaluate the effect of the lignin content in four hybrid poplars for enhancing ethanol production. The study was conducted using steam explosion at 200 and 220 degrees C for 5 min as a pre-treatment and then a simultaneous saccharification and fermentation (SSF) process with Saccharomyces cerevisiae. The composition of raw material, liquid, and solid fraction obtained after pretreatment, enzymatic digestion, and ethanol production under the different experimental conditions was analyzed. The best results for bioethanol production were obtained from steam explosion pre-treatment carried out at 220 degrees C with the hybrid poplar H-29, with cellulose recovery of over 63%, enzymatic hydrolysis yield of approximately 67%, and SSF yield of 70% of the theoretical value. However, the highest enzymatic hydrolysis yield (79%) was obtained for the hybrid poplar H-34, which has the lowest lignin content

Exploring an oxidative bleaching treatment for Chilean bamboo: a source of cellulose for biofuel generation and the nanotech industry

Quila (Chusquea quila) is a very abundant native Chilean bamboo species. This work reports on a delignification process which can be applied to quila to produce crystalline cellulose, an important resource for obtaining cellulose nanofibres or nanocrystals. Alternatively, the crystalline cellulose can then be subjected to fermentation processes, making it a useful raw material for biofuel production. The treatment studied is an oxidative treatment at low concentration (15% v/v), for short time periods (10, 20 min) and at temperatures between 100 and 140 degrees C, which produces alpha-cellulose fibres with high crystallinity (over 70%) and low residual lignin content (< 2%). The morphology of the cellulose fibres was analysed by scanning electron microscope, revealing a smooth surface containing many fibrils. Infrared spectroscopy was used to identify functional groups, showing that almost 99% of the lignin was removed. The crystallinity index of the cellulose fibres after the reaction was up to 79%, making it an excellent raw material for processing cellulose nanofibres required by the emerging nanotech industry. Carbohydrate analysis revealed 86% glucose and 14% xylose, which makes quila a promising candidate as a precursor for biofuel generation