First aid for flood-damaged paper using saltwater—Changes in paper properties and desalination methods—
Tunchira Bunyaphiphat1, Kenta Higashijima2 and Toshiharu Enomae1*
1University of Tsukuba and 2The University of Tokyo

2012 AD2011 AD2011 AD2011 AD2012 AD

2004 AD

2004 AD

Salt-Paperinteraction

Introduction

ResultSaltwater was successfully applied as a first-aid topreserve tsunami- or flood-damaged paper
No mould grew on copy paper immersed in seawaterof 3.5% or greater
Trichoderma reesei

0%

2.0%

Before soaking

NaCl solution

Distilled water

12

Mass gain ofpaper due to salt
particles remaining
in interfibre or
intrafibre pores or
attached to paper
surfaces

1086420

Moisture gain as
an effect of thedeliquescent salts
remaining in paper

3.5%

3.0%

Elution of dye inks was prevented

Toner
printedMiosture content (%)

Salt conc.

Dry mass of residual salt (%)

1. Influence of NaCl and MgCl2 solutions on paper properties

1098765432
10

Removal of salttended to decreasemoisture of paper
More salt remaining
in paper tended todecrease tensile
index for both ofNaCl and MgCl2
solutions-immersed
paper.

Inkjetprinted

Moisture contentand salt
crystallization
caused different
tensile indices of thecopy paper treatedby NaCl and MgCl2.

Concept
Step I: Salt inhibits
successfully mould
growthStep II: Is salt beneficial
to strength of copy
paper as handsheet?
Step III: If salt removal
is required, howeffectively is it
conducted?

Desalination afterimmersion
First aid forflood
damagedpaper

Salt-Paperinteraction

Copy paper

For Handsheet
treated with NaClsolution, theremaining salttended to increase
tensile index.

Residual salt in paper (%)

Handsheet
Handsheet

Methodology

For copy paper, highsizing degree andstarch applied forsurface sizing ofcopy paper provided
different fibreswelling behavior.

1. Influence of NaCl and MgCl2 solutions on paper
properties
Material:
Copy paper - P&W paper, 70 g/m2 (Fine PPC, Kishu Paper)
Handsheet - Hardwood bleached kraft pulp handsheet
Salt solution - NaCl at 3.5% (m/m)- MgCl2·6H2O ·at 1.6 % (m/m)

Immersion in distilledwater for 1 day(control)

Non-desalted

Desalted

Wiped(Salt-Wiped)

Immersion in 500
ml of distilledwater for 60s(Salt-60s)

Conductivity (mS/cm)

Immersion in 2 Liters of salt solution for 1 day(Original)

2. Desalination of paper immersed in salt solution
70

Copy Paper

460

Paper + salt solution 1 day50

Paper + salt solution 2 days

40

Salt solution

323020

1

10000

2000

4000

6000

Time (second)
Desalination speed was same irrespective of presence of paper in salt solution

3. Change of paper color after thermal drying

Fixed drying

White fine paperMoisture content, Paper mass, and Tensile index
Extraction by hot water

2. Desalination of paper immersed in salt solution
3.5 % (m/m) NaClsolution

Condu…

0220024002
6002
Time (second)

1 day

Corresponding author

Copy paper contains a slightamount of an direct azo dye Control
NaCl solwhich is strongly depositedon fibre surfaces. Color Cold water washing Hot water washingchange when MgCl2 salt
MgCl2 sol
MgCl2 sol
remained

NaCl sol
MgCl2 sol
CaCl2 solMgSO4 sol
Water(Control)

Conclusion

2 daysToshiharu Enomae, Life and Environmental Sciences,
University of Tsukuba, t@enomae.com

NaCl

Solution-immersed

Residual paper
Solution-immersed

1002 paper specimens( 645 mm2 each)

MgCl2Starch

Instrument:-Astom Acylizer S1-Membrane AC 220-10

Saltwater immersion method is appropriately used as first aid for floodor tsumani damaged paper due to the fact of Cheap-Easy-Fast effective
methodAcknowledgment

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Salt Science Research Foundation, Kurita Water and Environment
Foundation, and Mitsui & Co., Ltd., Environment FundThis poster is downloadable: