Aplicação de enzimas, extração e adição de hemiceluloses combinadas com ondas ultrassônicas para desenvolvimento de propriedades de papéis reciclados.

Abstract

Objetivou-se com este estudo a avaliação da capacidade de recuperação das propriedades dos papéis formados a partir de aparas de papelão ondulado pós-consumo pela combinação de diferentes técnicas. Para tanto, avaliou-se os efeitos da ação de diferentes grupos de enzimas, da extração e adição de hemiceluloses, do refino em moinho PFI e ultrassônico e da combinação destas tecnologias sobre as propriedades dos papéis formados. A verificação das modificações do potencial papeleiro das polpas e dos papéis formados foi realizada através de análises morfológicas e de propriedades higroscópicas das polpas e através de testes físicos e mecânicos dos papéis formados após serem submetidos às tecnologias anteriormente citadas. Também se avaliou a capacidade de redução dos componentes dos micros e macros stickies através dos tratamentos enzimáticos e os efeitos destes tratamentos anterior e posteriormente ao refino em moinho PFI; o potencial das ondas ultrassônicas para recuperação das propriedades de papéis reciclados, sua possível utilização e operação conjunta ao processo de refino mecânico convencional e análise comparativa de consumo de energia entre as duas tecnologias de refino; a ultrassonificação da polpa combinada com a adição de hemiceluloses. Os resultados mostraram que o modo de ação diversificado dos diferentes tipos de enzimas refletiu em diferenças nas características das polpas analisadas e acarretaram ganhos nas propriedades de resistência físicas e mecânicas nas polpas sem a necessidade de combinação com outras técnicas. As enzimas apresentaram capacidade de redução de componentes indesejáveis e causadores de stickies que compõe a polpa oriunda das aparas pós-consumo, reduzindo assim o potencial dos stickies. O tratamento enzimático posteriormente ao refino mostrou ser mais eficiente na melhoria de recuperação de características de resistência dos papéis, apresentando de modo geral, maiores valores que o tratamento anteriormente ao refino. Os resultados mostraram também que a tecnologia de ultrassonificação foi capaz de desenvolver as propriedades do papel reciclado, apesar das propriedades dos papéis que relacionam diretamente com as ligações interfibras mostrarem ser mais desenvolvidas pelo refino em moinho PFI. O tempo de tratamento, o consumo de energia e a capacidade de

The objective of this study was to evaluate the capacity recoverability of the properties of the papers formed from scraps of corrugated post-consumption by combining different techniques. Was studied the effects of the action of different enzymes, extraction and addition of hemicelluloses, refining in PFI mill and ultrasonic and combination of these technologies on the paper properties formed. The verification of the modifications of the potential papermaking and pulp was done through morphological analysis and hygroscopic properties of pulps and through physical and mechanical tests of the roles formed after undergoing the aforementioned technologies. Also was evaluated the capacity of reduction of components of micro and macro stickies through enzymatic treatments and the effects of these treatments before and after the refining in PFI mill; the potential of ultrasound waves to recover the properties of recycled papers, their possible use and operation in joint with the conventional mechanical refining to process and comparative analysis of energy consumption between the two refining technologies; ultrasonification of the pulp combined with the addition of hemicelluloses. The results showed that the mode of action of diverse types of enzymes reflected in differences in the characteristics of the pulps analyzed and led to gains in strength in the physical and mechanical properties of the pulps without the need for combination with other techniques. The enzymes were able to reduce unwanted components and causing of stickies that make up the pulp coming from post-consumer scraps, thus reducing so the potential of stickies. The enzymatic treatment after the refining was more effective in improving recovery of strength characteristics of papers, showing generally, higher values than the treatment prior to refining. The results also showed that technology of ultrasonification was able to develop the properties of recycled paper, although paper properties that relate directly to the links interfibers showed be more further developed by refining in PFI. The treatment time, energy consumption and production capacity appeared to be the major problems of ultrasonic technology in case of equipment used in this study. Still been verified that both the combination of refining in mill PFI with enzymatic treatments as the combination of ultrasonic and enzymatic treatments were effective in the development of papers properties evaluated. The filtered / effluent generated from the enzymatic treatments had values exceeding the limits established by law for release in water bodies, but when they were not mixed with other effluents from the process it was observed that the subsequent effluents had chemical and physical caracteristcs within the range allowed by law. The recirculation of filtered / effluents did not result in reduction of paper properties when compared with papers formed without recirculation. Finally, it was found that deposition of hemicelluloses occurred in the pulps submitted to refining in mill PFI, ultrasound and without refining being that the treatment in PFI mill provided the best conditions for the retention of the hemicelluloses dosed. The ultrasonic treatment followed by the addition of hemicelluloses showed be efficient in the development of mechanical strength properties of paper, promoting the development of properties, however, less pronounced than that observed when the pulp was refined in mill PFI followed by the addition of hemicelluloses. The pulp with lower content of hemicelluloses refines much more slowly than the containing a higher content of hemicelluloses.