State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China E-mail:
Water Sci Technol. 2020 Jan;81(2):301-308. doi: 10.2166/wst.2020.109.
The biodegradation of polyacrylamide (PAM) includes the hydrolysis of amino groups and cleavage of the carbon chain; however, the effect of molecular weight on the biodegradation needs further investigations. In this study, biodegradation of low molecular weight PAM (1.6 × 10 Da) was evaluated in two aerobic (25 °C and 40 °C) and two anaerobic (35 °C and 55 °C) reactors over 100 days. The removal of the low molecular weight PAM (52.0-52.6%) through the hydrolysis of amino groups by anaerobic treatment (35 °C and 55 °C) was much higher than that of the high molecular weight (2.2 × 10 Da, 11.2-17.0%) observed under the same conditions. The molecular weight was reduced from 1.6 × 10 to 6.45-7.42 × 10 Da for the low molecular weight PAM, while the high molecular weight PAM declined from 2.2 × 10 to 3.76-5.87 × 10 Da. The results showed that the amino hydrolysis of low molecular weight PAM is easier than that of the high molecular weight one, while the cleavage of its carbon chain is still difficult. The molecular weights of PAM in the effluents from the two aerobic reactors (25 °C and 40 °C) were further reduced to 4.31 × 10 and 5.68 × 10 Da by the biofilm treatment, respectively. The results would be useful for the management of wastewater containing PAM.
聚丙烯酰胺（PAM）的生物降解包括氨基的水解和碳链的断裂；然而，分子量对生物降解的影响需要进一步研究。在这项研究中，在两个需氧（25°C 和 40°C）和两个厌氧（35°C 和 55°C）反应器中，评估了低分子量 PAM（1.6×10 Da）在 100 天内的生物降解情况。通过厌氧处理（35°C 和 55°C）中氨基的水解，低分子量 PAM（52.0-52.6%）的去除率远高于在相同条件下观察到的高分子量 PAM（2.2×10 Da，11.2-17.0%）。低分子量 PAM 的分子量从 1.6×10 降低到 6.45-7.42×10 Da，而高分子量 PAM 从 2.2×10 降低到 3.76-5.87×10 Da。结果表明，低分子量 PAM 的氨基水解比高分子量 PAM 更容易，而其碳链的断裂仍然困难。在两个需氧反应器（25°C 和 40°C）中，生物膜处理将 PAM 的分子量进一步降低到 4.31×10 和 5.68×10 Da。这些结果将有助于管理含有 PAM 的废水。
