Liang Chenju, Tao Wei-Sin, Shih Chia-Lu, Ye Yi-Wun, Li Chun-Ting, Wang Chi-Wei
Department of Environmental Engineering, National Chung Hsing University, 145 Xingda Road, Taichung 402 402202, Taiwan.
Department of Environmental Engineering, Da-Yeh University, 168 University Road, Dacun, Changhua 515006, Taiwan.
ACS Omega. 2024 Nov 14;9(47):46943-46949. doi: 10.1021/acsomega.4c06522. eCollection 2024 Nov 26.
Rainwater flowing along the ground, and from hard surface such as pavement and roofs, becomes surface water runoff, which flows to surface waters, and infiltrates into the ground to become groundwater. Surface water runoff can contain elevated levels of nitrates (NO ) from various sources including animal wastes and fertilizers. Reducing elevated levels of NO in surface water runoff can minimize and/or prevent groundwater and surface water contamination. Natural polyphenols in carpet grass, due to phenolic hydroxyl groups, can degrade aqueous NO . This study evaluated the potential for carpet grass to purify water by denitrifying NO as surface water flows through grass-covered land. The research investigated nitrate removal efficiency and reaction kinetics under various flow rates and doses of carpet grass, validating the feasibility of using natural polyphenols for water purification. A grass dose of 100 g and a retention time of 24 h, which produced approximately 20-80 mg/L as gallic acid equivalent (GAE) of polyphenol in simulated surface water runoff, were demonstrated to effectively degrade NO in aqueous solution (110 mg/L) and result in the denitrification of NO to nitrite (NO ) and eventually N. The first-order reaction kinetic rate constants for NO degradation, NO formation, and subsequent degradation of NO are = 6.89 × 10 h, = 5.11 × 10 h, and = 4.63 × 10 h, respectively, with a conversion rate (α) of NO to NO to be 0.74. Implementing natural vegetation, such as carpet grass, in water management practices offers an environmentally sustainable approach to reducing nitrate contamination in surface water runoff.
沿地面流动以及从人行道和屋顶等硬质表面流下的雨水会形成地表径流，这些径流流入地表水，并渗入地下成为地下水。地表径流可能含有来自动物粪便和肥料等各种来源的高浓度硝酸盐（NO ）。降低地表径流中过高的NO 水平可以最大限度地减少和/或防止地下水和地表水受到污染。地毯草中的天然多酚由于含有酚羟基，可以降解水中的NO 。本研究评估了地毯草在地表水通过草地时通过反硝化作用去除NO 从而净化水的潜力。该研究调查了不同流速和地毯草用量下的硝酸盐去除效率和反应动力学，验证了使用天然多酚进行水净化的可行性。结果表明，在模拟地表径流中，100克的草用量和24小时的停留时间可产生约20 - 80毫克/升（以没食子酸当量计）的多酚，能有效降解水溶液中的NO （110毫克/升），并使NO 反硝化生成亚硝酸盐（NO ），最终生成氮气。NO 降解、NO 生成以及随后NO 降解的一级反应动力学速率常数分别为 = 6.89 × 10 h、 = 5.11 × 10 h和 = 4.63 × 10 h，NO 转化为NO 的转化率（α）为0.74。在水管理实践中采用地毯草等天然植被，为减少地表径流中的硝酸盐污染提供了一种环境可持续的方法。
