Biodegradability of a polyacrylate superabsorbent in agricultural soil

Abstract

Superabsorbent polymers (SAP) are used, inter alia, as soil amendment to increase the water holding capacity of soils. Biodegradability of soil conditioners has become a desired key characteristic to protect soil and groundwater resources. The present study characterized the biodegradability of one acrylate based SAP in four agricultural soils and at three temperatures. Mineralisation was measured as the (13)CO₂ efflux from (13)C-labelled SAP in soil incubations. The SAP was either single-labelled in the carboxyl C-atom or triple-labelled including additionally the two C-atoms interlinked in the SAP backbone. The dual labelling allowed estimating the degradation of the polyacrylate main chain. The (13)CO₂ efflux from samples was measured using an automated system including wavelength-scanned cavity ring-down spectroscopy. Based on single-labelled SAP, the mean degradation after 24 weeks varied between 0.45% in loamy sand and 0.82% in loam. However, the differences between degradation rates in different soils were not significant due to a large intra-replicate variability. Similarly, mean degradation did not differ significantly between effective temperature regimes of 20° and 30 °C after 12 weeks. Results from the triple-labelled SAP were lower as compared to their single-labelled variant. Detailed results suggest that the polyacrylate main chain degraded in the soils, if at all, at rates of 0.12-0.24 % per 6 months.

Poly(Alkyl Glycidate Carbonate)s as Degradable Pressure‐Sensitive Adhesives

“…[45] In contrast, polycarbonates are known to degrade by UV radiation, oxidative cleavage,w ater erosion, as well as microbial;t herefore,p olycarbonate life expectancy peaks at 3years. [45] In contrast, polycarbonates are known to degrade by UV radiation, oxidative cleavage,w ater erosion, as well as microbial;t herefore,p olycarbonate life expectancy peaks at 3years.…”

“…Aliphatic polymers are immune to most degradation methods and are only degraded by specific microbes.T he process itself is long and, thus,p olyacrylates exhibit main chain degradation in soil at arate of 0.12 %per 6month, if at all. [45] In contrast, polycarbonates are known to degrade by UV radiation, oxidative cleavage,w ater erosion, as well as microbial;t herefore,p olycarbonate life expectancy peaks at 3years. [46] To evaluate the effect of introducing ac arbonate linkage into the polymer backbone on degradation, studies with PEAc,P GC-E, and PEA were conducted over a3 5day period (Figure 4).…”

Polymers and its applications in agriculture

“…They proposed a hydrolysis process from Si-O-C bonds in aqueous solution which degraded the hybrid hydrogels in a matter of days. Wilske et al [107] characterized the biodegradability of SAP based on polyacrylate for Tl(II) [89] Green coconut shell Fibers (polysaccharide) 22.96 mg g -1 Cr(VI) [90] Chitosan polysaccharide 36.8 mg g -1 Pb(II) [91] Sawdust polysaccharide 26 mg g -1 (Pb) Pb(II) [92] 22 Cr(VI) [93] Rice straw Cellulose, hemicellulose and lignin 30.0 mg g -1 (Cr) Cr(III) [94] 22.5 mg g -1 (Cu) Cu(II)…”

A Review of the Latest in Phosphorus Fertilizer Technology: Possibilities and Pragmatism

“…Additionally, the impact of these organic compounds on long‐ and short‐term soil health remains to adequately assessed. Some suggest that soil physical properties, such as aggregation and water‐holding capacity, can be greatly enhanced, but the response of components, like the soil microbial community, requires investigation (Wilske et al, 2014). …”