Hoi-shan Kwan. / Thesis (M. Phil.)--Chinese University of Hong Kong. / Bibliography: leaves 104-115.

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Mainly used food packaging materials are petro-chemical based polymers which present environmental problems since they are not biodegradable and ecologically sustainable. In this study, biodegradable biofilms are produced from xylan, extracted from cotton stalk which is an agricultural biowaste without nutritional value. Antimicrobial property was given to the biofilms with either titanium dioxide sol-gel coatings or titanium dioxide powder addition into the biofilm forming solutions. The antimicrobial activities of biofilms were tested against Escherichia coli. Among two different sol-gels coated and at different temperatures dried biofilms, BWX and CSX-50 biofilms treated at 120&deg / C and coated with SiO2/TiO2 showed 88&plusmn / 1% and 75&plusmn / 2% antimicrobial activities, respectively. Same samples treated at the same conditions but coated with non-SiO2 added TiO2 sol-gel yielded 63&plusmn / 3% and 63&plusmn / 2% antimicrobial activities, respectively after 2 h black light illumination. So, it was determined that the highest photocatalytic antimicrobial property was achieved with SiO2/TiO2 coated biofilms. Moreover different concentrations of TiO2 powder were integrated into xylan based biofilms and 100% photocatalytic inactivation was gathered at 5% (w/w) TiO2 addition achieved at both biofilms at the end of 90 min black light illumination. Biodegradability properties of the biofilms were investigated in soil burial test during 180 days and 10% (w/w) TiO2 powder added CSX-50 biofilms were recorded to be 91% biodegradable where non-powder added blank biofilms was found to be 95% biodegradable.

Xylan was extracted from cotton waste, characterized by DSC and TGA analysis and used in biodegradable film production. Pure cotton waste xylan did not form film. The presence of an unknown compound, as an impurity, yielded composite films. The unknown compound was determined as a phenolic compound, and most probably lignin, by using DSC and TGA analysis and Folin-Ciocalteau method. The effects of xylan concentration of the film forming solutions, glycerol (plasticizer) and gluten additions on thickness, mechanical properties, solubility, water vapor transfer rate, color and microstructure of the films were investigated. Films were formed within the concentration range of 8-14%. Below 8%, film forming solutions did not produce films, whereas xylan concentrations above 14% was not used because of high viscosity problems. The average tensile strength, strain at break, water vapor transfer rate and water solubility of the cotton waste xylan films were determined as about 1.3 MPa, 10%, 250 g/m2.24h and 99%, respectively. The addition of glycerol as the plasticizer resulted in a decrease in the tensile strength and an increase in strain at break. The change in water solubility due to the addition of glycerol was very small. In addition, water vapor transfer rate and the deviation of the color from the reference color for the plasticized films were found to be higher than the unplasticized films. The effect of addition of wheat gluten in cotton waste xylan film forming solutions on film formation was investigated at different concentration ratios. However, the incorporation of wheat gluten worsen the film quality.

Made available in DSpace on 2015-03-26T13:28:13Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1348955 bytes, checksum: f1f339aecdf1f00f202d0669a29a4e69 (MD5) Previous issue date: 2012-10-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this research was to study the technical feasibility of using the solid wastes, biological sludge and cotton residues, generated by the textile mill, as raw material in the production of briquettes for energy generation. Initially, the study aimed to characterize the solids waste, in order to evaluate their potential as fuels in energy generation. Subsequently, the biological sludge was mixed with cotton residues in proportions of 0, 25, 50, 75 and 100%, to produce of the briquettes. Three pressures (900, 1200 and 1500 PSI) were used for waste compaction for five minutes and a temperature of 90ºC was maintained during the cooling time, of also five minutes. The calorific value, chemical analysis, apparent density, rupture load and hygroscopic moisture equilibrium were determined. In order to study the environmental effects of the solid waste combustion, the hazardousness of the waste and residual ashes was determined. According to the results, the biological sludge and cotton residues were classified as non-hazardous and non-inert wastes (Class II A). The physical and chemical properties of the solid waste showed that they have potential for energy production. The ashes were classified as hazardous wastes (Class I), thus they should be treated and disposed properly. The briquettes showed lower content of the volatile matter and, consequently, higher content of fixed carbon and ashes in relation to raw materials for this production, which demonstrates the effect of the briquetting process variables. The high calorific value of the briquettes did not differ to the raw materials commonly used. The compaction pressure of 1200 PSI proved ideal to the laboratory scale briquetting process. The best mixing proportion between the two residues for production of briquettes was that with 25% sludge. It was possible to conclude that waste from a textile mill can be considered as fuel in the combustion process for power generation. / Esta pesquisa foi realizada com o objetivo de estudar a viabilidade técnica de utilizar os resíduos sólidos, lodo biológico e resíduo de algodão, gerados pela indústria têxtil, como matéria-prima para a produção de briquetes para a geração de energia. Buscou-se, inicialmente, caracterizar os resíduos, a fim de se avaliar o potencial destes como combustíveis na geração de energia. Posteriormente, o lodo biológico foi misturado com o resíduo de algodão, nas proporções de 0%, 25%, 50%, 75% e 100%, para a fabricação dos briquetes. Foram utilizadas três pressões (900, 1.200 e 1.500 PSI) para a compactação dos resíduos, durante 5 minutos e tempo de resfriamento também de 5 minutos, à temperatura de 90 ºC. Determinaram-se o poder calorífico, a análise química imediata, a densidade aparente, a carga de ruptura máxima e a umidade de equilíbrio higroscópico dos briquetes. Para avaliar os efeitos ambientais da combustão destes resíduos, determinou-se a periculosidade dos resíduos e de suas cinzas residuais. De acordo com os resultados, o lodo biológico e o resíduo de algodão foram classificados como resíduos não perigosos e não inertes (Classe II A). As propriedades físicas e químicas dos resíduos demonstraram que os mesmos apresentam potencial para a produção de energia. As cinzas foram classificadas como resíduos perigosos (Classe I) e, sendo assim, devem ser tratadas e dispostas adequadamente. Os briquetes apresentaram menor teor de materiais voláteis e, consequentemente, maior teor de carbono fixo e cinzas, em relação às matérias-primas utilizadas para a sua produção, evidenciando efeito das variáveis do processo de briquetagem. O poder calorífico superior obtido nos briquetes não diferiu das matérias-primas utilizadas. A pressão de compactação de 1.200 PSI mostrou-se ideal para o processo de briquetagem em escala laboratorial. A melhor proporção de mistura entre os dois resíduos para a produção dos briquetes foi a 25% de lodo. Conclui-se que os resíduos da indústria têxtil podem ser considerados como combustível no processo de combustão para a geração de energia.

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