Department of Civil, Architectural and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA.
Water Environ Res. 2012 Jul;84(7):569-76. doi: 10.2175/106143012x13373575830593.
Effects of nano-copper(II) oxide (nano-CuO) and nanomagnesium oxide (nano-MgO) particles on activated sludge endogenous respiration (aerobic digestion), biochemical oxygen demand (BOD) biodegradation, and nitrification were investigated through respiration rate measurement. For comparison, the effects of Cu(II) and Mg(II) ions on activated sludge were also studied. Results indicated that soluble Cu(II) has half maximum inhibitory concentration (IC50) values of 19, 5.5, 53, and 117 mg Cu/L for endogenous respiration, BOD biodegradation, ammonium oxidation, and nitrite oxidation, respectively. However, nano-CuO only inhibited BOD biodegradation at 240 mg Cu/L or more, and its associated toxicity was primarily caused by soluble Cu(II). In contrast, soluble Mg(II) was not toxic to activated sludge in the experimental concentration range, but nano-MgO inhibited BOD biodegradation and nitrification with IC50 values of 70 and 143 mg Mg/L, respectively. Further study indicated that the toxicity of nano-MgO resulted primarily from increased pH following MgO hydrolysis.
通过呼吸速率测定，研究了纳米氧化铜（nano-CuO）和纳米氧化镁（nano-MgO）颗粒对活性污泥内源呼吸（好氧消化）、生化需氧量（BOD）生物降解和硝化的影响。为了进行比较，还研究了 Cu(II) 和 Mg(II) 离子对活性污泥的影响。结果表明，可溶性 Cu(II) 对内源呼吸、BOD 生物降解、氨氧化和亚硝酸盐氧化的半最大抑制浓度（IC50）值分别为 19、5.5、53 和 117mg Cu/L。然而，纳米 CuO 仅在 240mg Cu/L 或更高浓度下才抑制 BOD 生物降解，其相关毒性主要是由可溶性 Cu(II) 引起的。相比之下，在实验浓度范围内，可溶性 Mg(II) 对活性污泥没有毒性，但纳米 MgO 分别以 70 和 143mg Mg/L 的 IC50 值抑制 BOD 生物降解和硝化。进一步的研究表明，纳米 MgO 的毒性主要源于 MgO 水解后 pH 值的升高。
