Calcium hydroxide nanoparticles from solvothermal reaction for the deacidification of degraded waterlogged wood

Published Date
1 July 2016, Vol.473:1–8, doi:10.1016/j.jcis.2016.03.038

Title 
Calcium hydroxide nanoparticles from solvothermal reaction for the deacidification of degraded waterlogged wood

• Author 

• Giovanna Poggi ^a,
• Nicola Toccafondi ^a,
• David Chelazzi ^a,
• Patrizia Canton ^b,
• Rodorico Giorgi ^a,
• Piero Baglioni ^a,,

• aDepartment of Chemistry & CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
• bDepartment of Physical Chemistry and CSGI, University of Venice Ca’ Foscari, 30170 Venezia, Italy

Received 1 February 2016. Revised 15 March 2016. Accepted 17 March 2016. Available online 18 March 2016.

Abstract

Hypothesis

A combination of acid and iron ions inside the wood has been corroding the cellulose matrix of the Swedish warship Vasa, imposing its deacidification. Past deacidification treatments displayed poor penetration inside the wood matrix with limited efficacy. A vacuum assisted treatment of wood using newly developed calcium hydroxide nanoparticle dispersions represents a possible candidate for the treatment of acidic waterlogged wood objects such as sculptures and decorative artifacts.

Experiments

A solvothermal process was used for the synthesis of calcium hydroxide nanoparticle dispersions. Before the application on waterlogged wood, the physico-chemical characterization of these systems was carried out using several techniques. The efficacy of the deacidification treatment of wood samples from the Vasa was assessed by determination of pH and Differential Thermal Gravimetric (DTG) measurements.

Findings

The proposed solvothermal reactions can be used to produce stable and highly concentrated calcium hydroxide nanoparticle dispersions in alcohols, needing no further purification before the application. This process has also the advantage to be upscalable to industrial level. Both pH and DTG measurements showed that the newly developed dispersions can homogenously penetrate inside the wood up to 20 cm, neutralizing acidity and creating an alkaline buffer inside the wooden matrix, to hinder the degradation of residual cellulose.

Graphical abstract

Keywords

• Deacidification
• Wood
• Vasa
• Calcium hydroxide nanoparticles
• pH-adjustment
• Cellulose

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• DOCX (163K)

Supplementary Tables and Figures

• ⁎ 
  Corresponding author.

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http://www.sciencedirect.com/science/article/pii/S0021979716301801