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Water purification using functionalized cellulose with non-leaching bacteria adsorbing properties
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. (Wood Chemistry and Pulp Technology)ORCID iD: 0000-0002-1656-1465
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.ORCID iD: 0000-0003-1812-7336
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Portable purification systems are easy ways to obtain clean drinking water when there is no large-scale water treatment available. In this study, the potential to purify water using bacteria adsorbing cellulose functionalized with polyelectrolytes, according to the Layer-by-Layer method, is investigated. The adsorbed polyelectrolytes create a positive charge on the cellulose surface that physically attracts and bonds with bacteria. Three types of cellulose material have been modified and tested for the bacterial removal capacity in water. The time, material-water ratio and bacterial concentration dependence, as well as the bacterial removal capacity in water from natural sources, have been evaluated. Freely dispersed bacteria adsorbing cellulose can remove greater than 99.9% of Escherichia coli from non-turbid water, with the most notable reduction occurring within the first hour. For turbid water, a filtering approach using modified cellulose fibers is desirable. This bacteria adsorbing cellulose does not leach any biocides, and it is an environmentally sustainable and cheap option for disposable water purification devices.

Keyword [en]
Contact-active material, emergency treatment, polyelectrolyte multilayer
National Category
Paper, Pulp and Fiber Technology
Research subject
Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-204508OAI: oai:DiVA.org:kth-204508DiVA: diva2:1085022
Note

QC 20170328

Available from: 2017-03-27 Created: 2017-03-27 Last updated: 2017-03-28Bibliographically approved
In thesis
1. Water purification using polyelectrolyte modified cellulose fibers and filters to adsorb bacteria
Open this publication in new window or tab >>Water purification using polyelectrolyte modified cellulose fibers and filters to adsorb bacteria
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Clean water is necessary for human survival and there is a need for development of cheap and easy water purification techniques to use in emergency situations when there is no access to safe drinking water. Bacteria contaminated water can cause lethal diarrheal diseases and is globally the second most common cause of death among children less than five years of age.

Bacteria adsorbing filter paper made from cellulose could be an environmentally and economically sustainable alternative for disposable water purification filters. This thesis investigates the possibility to use polyelectrolyte multilayer modified cellulose pulp fibers and filter papers to adsorb and remove bacteria from water. The bacterial removal efficiency of the modified materials has been tested both in suspension and through filtration.

The surface modification provides the cellulose fibers with a positively charged surface that can attract and bind the negatively charged bacteria. The bacterial adsorption through electrostatic interactions makes it possible to remove bacteria, even when the pore size of the cellulose filters is larger than bacteria. Bacterial reduction tests shows that it is possible to remove over 99.9 % of the bacteria when filtering water through the modified materials. An increased amount of adsorbed cationic polyelectrolyte, polyvinylamine, resulted in an increased bacterial removal capacity. It has also been shown that the bacterial removal efficiency increases with an increased the amount of bacteria adsorbing materials in the filter.

The modified materials have been compared with a commercial product and the filtration efficiency has shown to be greater for the polyelectrolyte-modified materials, under the test conditions used in this thesis. Tests with natural water samples shows that it is important to use a filtration mode to remove particles from the water in combination with the bacterial adsorption, as the particles interfere with the bacterial adsorption.

Abstract [sv]

Säkert dricksvatten är nödvändigt för överlevnad och det finns ett stort behov av att utveckla nya billiga och enkla tekniker för att rena vatten i nödsituationer där det inte finns tillgång till detta. Dricksvatten förorenat av bakterier kan orsaka dödliga diarrésjukdomar och är globalt den näst vanligaste dödsorsaken bland barn under fem år.

Denna avhandling undersöker möjligheten att använda cellulosafibrer och filterpapper, ytmodifierade med multilager av katjoniska polyelektrolyter, för att adsorbera och avlägsna bakterier från vatten. Bakterieradsorberande filterpapper tillverkat av cellulosa kan vara ett miljövänligt och ekonomiskt hållbart alternativ för vattenreningsfilter för engångsbruk. De modifierade materialens förmåga att adsorbera bakterier har testats både i suspension och via filtrering.

Ytmodifieringen ger cellulosafibrerna en positivt laddad yta som kan attrahera och binda de negativt laddade bakterierna. Avlägsnandet av bakterier genom elektrostatisk interaktion gör det möjligt att ta bort bakterier, även när filtret har en porstorleken som är större än bakterierna.

Bakteriereduktionstesterna visar att det är möjligt att avlägsna mer än 99,9 % av bakterierna vid filtrering genom de modifierade materialen. En ökad mängd adsorberad katjonisk polyelektrolyt, polyvinylamin, resulterade i en ökad bakterieavlägsningskapacitet. Det har också visat sig att effektivitet ökar väsentligt med ökad mängd bakterieadsorberande material i vattenfiltren.

De ytmodifierade materialen har jämförts med en kommersiell produkt för vattenrening med goda resultat. Filtreringstesterna utförda i den här avhandlingen visar att de modifierade materialen tar bort mer bakterier än vad det kommersiella filtret inaktiverar. Tester med naturliga vattenprov visar att det är viktigt att använda filtrering för att avlägsna partiklar från vattnet för att uppnå en önskad bakterieadsorption, eftersom partiklarna påverkar bakterieadsorptionen och minskar effektiviteten hos de bakterieadsorberande materialen

Place, publisher, year, edition, pages
Stockholm: Kungliga Tekniska högskolan, 2017. 50 p.
Series
TRITA-CHE-Report, ISSN 1654-1081 ; 2017:18
Keyword
Bacterial adsorption, cellulose filter, Layer-by-Layer, water treatment
National Category
Paper, Pulp and Fiber Technology
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-204511 (URN)978-91-7729-326-2 (ISBN)
Presentation
2017-04-28, K1, Teknikringen 56, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20170328

Available from: 2017-03-28 Created: 2017-03-27 Last updated: 2017-03-29Bibliographically approved

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