【摘要】 采用实验室培养的方式,研究大薸(Pistia stratiotes)在处理某电镀厂微污染含铬废水的净化效果及其机理。实验结果表明,7 d内,大薸(200 g,鲜重)对20 L含铬废水(铬(Ⅵ)0.5 mg/L,总铬为2.0 mg/L)的铬(Ⅵ)和总铬清除率分别为99.4%和71.6%;被吸收的铬离子主要分布在根部,占吸收总量的68.3%。通过对比分析试验组和对照组根系分泌物和植株体内化学成份,可见大薸对微污染含铬废水的适应机制为:(1)大薸根部分泌出大量的有机酸、糖和氨基酸及蛋白类等,有机酸等将含铬废水中毒性较大的铬(Ⅵ)还原成毒性较小的铬(Ⅲ),缓解其毒害作用。(2)大薸合成大量植物络合物(PCs)降低已吸收的铬离子对植株的毒害作用。更多还原

【Abstract】 The laboratory experiments were done to study the removal effect and mechanism of Pistia stratiotes on treating micro-polluted wastewater of chromium. The experimental results showed that the removal rate of Pistia stratiotes, incubating in 20 litres chromium-containing wastewater(Cr(Ⅵ) 0.5 mg/L, total chromium 2.0 mg/L) in seven days, on chromium(Ⅵ) and total chromium were 99.4% and 71.6% respectively. The chromium ions were mainly in the roots, accounting for 68.3% of the total. According to the measurement of the root exudates and the chemical composition of the plants, it can be considered that the adaptational mechanism of the P. stratiotes to the micro-polluted wastewater of chromium was as follows: the root of P. stratiotes excreted large amounts of organics which mainly includes organic acids,carbohydrate, amino acids and proteins. Organic acids can reduce chromium(Ⅵ)(more toxic) to chromium(Ⅲ)(less toxic) in chromium-containing wastewater, to alleviate its toxic effects. Large quantities of plant complexes(PCs) in the experimental group(chromium-containing wastewater) were synthesized to reduce the toxic effects of absorbing chromium ions in P. stratiotes.更多还原