Biodegradability of a polyacrylate superabsorbent in agricultural soil
Biodegradability of a polyacrylate superabsorbent in agricultural soil
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DOI：
10.1007/s11356-013-2103-1
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发表时间：
2014-08-01
影响因子：
5.8
通讯作者：
Breuer, Lutz
中科院分区：
文献类型：
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作者：
Wilske, Burkhard;Bai, Mo;Breuer, Lutz
高吸水性聚合物(SAP)被用作土壤改良剂，以增加土壤的持水能力。土壤改良剂的生物降解性已成为保护土壤和地下水资源的重要指标。本文研究了一种丙烯酸酯类保水剂在四种农田土壤和三种温度下的生物降解性。在土壤培养中，矿化被测量为(CO2)-C-13从C-13标记的树液中流出。SAP要么在羧基C原子中被单标记，要么被三标记，另外还包括在SAP主干中相互连接的两个C原子。双标记法可以估计聚丙烯酸酯主链的降解程度。使用包括波长扫描腔衰荡光谱在内的自动化系统测量样品中的(CO2)-C-13外流。基于单一标记的SAP，24周后的平均降解率在壤沙的0.45%和壤土的0.82%之间变化。然而，不同土壤的降解率之间的差异并不显著，这是因为重复内变异很大。同样，在20摄氏度和30摄氏度的有效温度范围内，12周后的平均降解率没有显著差异。与单标记变异体相比，三标记SAP的结果较低。详细的结果表明，聚丙烯酸酯主链在土壤中的降解速度为每6个月0.12-0.24%。
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 (CO2)-C-13 efflux from C-13-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 (CO2)-C-13 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 20A degrees and 30 A degrees 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.