| Author | Heydarifard, Solmaz |
| Note | A dissertation submitted in partial fulfillment of the requirements for the
degree of Doctor of Philosophy in Pulp and Paper Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | The purpose of this study was to find a household-level water treatment that can be affordable by poor people. The most proper point-of-use water treatment is water filtration. Currently, the most utilized filtration membranes are made from synthesized polymers that are not environmentally friendly. There is increased awareness on a global scale of the need for biodegradable and environmental friendly products. Thus, substituting biodegradable and environmentally-friendly materials for non-renewable and petroleum-based polymers is strongly recommended. Biodegradability and naturalness of materials are important factors in this attempt to find adequate water filtration membranes for water-treatment solutions. Cellulose foam paper is a novel porous material made of the most abundant biodegradable polymer: cellulose. It could be used as water filtration membrane. Cellulose foam papers are capable of providing products with high specific surface area and tortuous structure favorable for entrapping particles while providing excellent permeability for incoming water. For converting this material to water membrane, two modifications which are improvement of wet strength performance and converting cellulose foam filter to antibacterial substrate should be performed.
Cellulose foam paper has minimal strength, much less than a paper handsheet, due to its bulky structure. For applying this as water membrane, it needs to have high strength when exposed to the moist environment. For wet strength improvement two approaches were followed which were furnish formulation like refining that increases the fibers‘ binding area and addition of wet strength agents like glutaraldehyde and polyvinyl alcohol generating cross-linking between fibers and improve the inter-fiber bonds.
Cellulose foam filter as water filter should not only remove the particulate materials, but also it should be capable of removing or deactivating the pathogenic microbes available in the water. Although, a small part of bacteria, protozoa and molds are removed by the filter, they are not deactivated. Thus, modifying the antibacterial properties of cellulose foam paper was the other objective of this research. For this purpose, two biodegradable polymers were incorporated in the foam filter samples: polyhexamethylene guanidine hydrochloride (PHGH) and ε-polylysine (ε-PL) modified starch. Two tests were carried out on modified samples, the shake flask test and the filtering test. At the end, non-leaching effects were tested for each of the important antibacterial factors.
The morphology analysis of cellulose foam paper revealed its 3-dimensional high porosity and non-uniform pores size which made it suitable for applying it as water filtration membrane. Water resistance performance of cellulose foam filter was improved with different treatments and wet strength agent additions. High molecular weight cationic polyacrylamide caused to improve the interfiber bonding in foam paper. Glutalradehyde and poly vinyl alcohol additions along with C-PAM reinforced the foam filter‘s wet strength properties and made it durable. Conversion of cellulose foam filter to biocidal filter was the last step which gave high performance in deactivating E.coli as a famous pathogenic microbe exited in water. |
| Year | 2016 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Pulp and Paper Technology (PP) |
| Chairperson(s) | Shipin, Oleg ; |
| Examination Committee(s) | Hornyak, Gabriel Louis ;Bohez, Erik L. J. ;Oslon, James Allen ;Enomae, Toshiharu ; |
| Scholarship Donor(s) | Partially AIT Fellowship; |