自然水体生物膜体系中过氧化氢浓度的影响因素

Investigation on the Factors Affecting Hydrogen Peroxide Concentrations in Natural Biofilm Systems

以过氧化氢（H2O2）为自然水体生物膜产生的活性氧（ROS）的代表,通过模拟实验,研究了水-自然水体生物膜体系中光/暗变化、生物膜的避光预处理与数量、有机配体和p H值对体系中H2O2浓度的影响.结果表明,光照可快速增加体系中H2O2浓度,光照转为无光时体系H2O2浓度下降（约为光照时的2/3）;避光预处理会显著降低体系中H2O2的产生速率和浓度;生物膜数量的增减会导致体系H2O2浓度的相应增减;有机配体的存在会使体系内H2O2浓度下降（约1/2~1/3）;p H=7和5的体系中H2O2的浓度高于p H=9的体系（高出约1.5倍）.上述各因素主要通过影响生物膜生产H2O2、H2O2自然分解和生物膜去除H2O23种作用来影响体系H2O2浓度.

In this study, hydrogen peroxide（H2O2） was selected as a representative of reactive oxygen species （ROS） to investigate the effect of factors, such as light/dark variation, dark pretreatment of biofilms, biofilm quantity, presence of ligands and pH value of the solutions, on H2O2 concentrations in natural biofilmswater systems. The results indicated that H2O2 concentration increased rapidly under illumination, and the H2O2 concentration decreased（ to about 2/3） when the systems switched to darkness. Dark pretreatment significantly reduced both the H2O2 concentrations and the increasing rate. The increase and decrease of biofilm quantity led to corresponding change of H2O2 concentrations in the systems. The presence of organic ligands reduced the H2O2 concentrations （by about 1/2-1/3 ）. H2O2 concentrations in neutral and acidic systems （pH = 7 and 5 ） were about 1.5 times as high as that in basic system （pH = 9 ）. These factors affected H202 concentrations in the biofilm systems by affecting three key processes, which were H2O2 generation of natural biofilms, H2O2 decomposition and H2O2 removal by biofilms.