Accession Number : ADA603476
Title : Pretreated Starch Solutions for Low Environmental Impact Aircraft Deicing
Descriptive Note : Final rept.
Corporate Author : WASHINGTON STATE UNIV PULLMAN
Personal Author(s) : Watts, Richard J
Report Date : Sep 2010
Pagination or Media Count : 38
Abstract : Objectives. Deicers currently used for aircraft deicing, including ethylene glycol and propylene glycol, pose significant threats to surface waters. Oxidized starch may provide a less toxic deicer with lower biochemical oxygen demand. The objectives of this research were to 1) evaluate freezing point depression of different starch formulations, 2) determine the biological oxygen demand and aquatic toxicity of the most effective formulation, and 3) to provide a preliminary evaluation of compatibility of oxidized starch solutions with aircraft materials. Technical Approach. Starch solutions were oxidized using hydrogen peroxide and catalysts. The oxidized starch solutions were evaluated for freezing point depression and post-treated to reduce viscosity. The most effective formulation was then evaluated for oxidation products, corrosivity, aquatic toxicity, and biochemical oxygen demand. Results. Freezing point depression of oxidized starch formulations ranged from 19.7 to 28 C; viscosities similar to those of commercially available deicers were after post-treatment with granular activated carbon. Oxidized starch exerted a BOD5 up to six times lower than glycol deicers; toxicity was greater than pure propylene glycol but lower than propylene glycol deicer formulations. Corrosion testing indicated compatibility with aerospace materials in most cases. Organic acids were identified by gas chromatography/mass spectrometry as the primary constituents in the oxidized starch solution and their sodium salts are likely responsible for freezing point depression. Benefits. The proposed deicing system would provide effective aircraft deicing while exerting minimal environmental effects (e.g., lower toxicity to aquatic organisms and lower biochemical oxygen demand). Furthermore, these deicers could be made from waste starch, promoting sustainability within DoD.
Descriptors : *DEICING MATERIALS , *ENVIRONMENTAL IMPACT , *STARCHES , AIRCRAFT , CHEMICAL ANALYSIS , CORROSION , FOAM , FREEZING , HYDROGEN PEROXIDE , OXIDATION , SUBSTRATES , TOXICITY , VISCOSITY
Subject Categories : Biochemistry
Snow, Ice and Permafrost
Environmental Health and Safety
Distribution Statement : APPROVED FOR PUBLIC RELEASE