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Bai, M.* ; Wilske, B.* ; Buegger, F. ; Esperschütz, J. ; Bach, M.* ; Frede, H.-G.* ; Breuer, L.*

Relevance of nonfunctional linear polyacrylic acid for the biodegradation of superabsorbent polymer in soils.

Environ. Sci. Pollut. Res. 22, 5444-5452 (2015)
DOI
Open Access Green as soon as Postprint is submitted to ZB.
Biodegradability is a desired characteristic for synthetic soil amendments. Cross-linked polyacrylic acid (PAA) is a synthetic superabsorbent used to increase the water availability for plant growth in soils. About 4 % within products of cross-linked PAA remains as linear polyacrylic acid (PAAlinear). PAAlinear has no superabsorbent function but may contribute to the apparent biodegradation of the overall product. This is the first study that shows specifically the biodegradation of PAAlinear in agricultural soil. Two 13C-labeled PAAlinear of the average molecular weights of 530, 400, and 219,500 g mol−1 were incubated in soil. Mineralization of PAAlinear was measured directly as the 13CO2 efflux from incubation vessels using an automatic system, which is based on 13C-sensitive wavelength-scanned cavity ring-down spectroscopy. After 149 days, the PAAlinear with the larger average molecular weight and chain length showed about half of the degradation (0.91 % of the initial weight) of the smaller PAAlinear (1.85 %). The difference in biodegradation was confirmed by the δ13C signature of the microbial biomass (δ13Cmic), which was significantly enriched in the samples with short PAAlinear (−13 ‰ against reference Vienna Pee Dee Belemnite,VPDB) as compared to those with long PAAlinear (−16 ‰ VPDB). In agreement with other polymer studies, the results suggest that the biodegradation of PAAlinear in soil is determined by the average molecular weight and occurs mainly at terminal sites. Most importantly, the study outlines that the size of PAA that escapes cross-linking can have a significant impact on the overall biodegradability of a PAA-based superabsorbent.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords Polymer mineralization; Polyacrylate; Water superabsorbent polymer (SAP); 13CO2 efflux; Microbial Biomass-c; Degradation; Extraction; Growth; Model; Trees; Wheat; Water
ISSN (print) / ISBN 0944-1344
e-ISSN 1614-7499
Journal Environmental Science and Pollution Research
Quellenangaben Volume: 22, Issue: 7, Pages: 5444-5452 Article Number: , Supplement: ,
Publisher Springer
Publishing Place Heidelberg
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Institute of Soil Ecology (IBOE)
Research Unit Comparative Microbiome Analysis (COMI)