紫外发光二极管与脉冲紫外对藻类及其衍生有机物的控制机制研究

Low penetration, single emission wavelength and low irradiation density were the critical limitations of UV mercury vapor lamp for the pre-treatment of algae-contained water. Novel pulsed ultraviolet (PUV) light source is characterized by continuous emission spectrum and high penetration, and it can be an option for algae-contained water pre-treatment. In current study, the ultraviolet light emitting diode (UV-LED) with single wavelength will be used to assess the intrinsic decomposition mechanisms of photosynthesis, enzyme and gene systems in algae cells. This study will provide several optimized "wavelength-irradiation density" distribution patterns for PUV selection. After determination of PUV type, light wavelength filter technique will be used to identify the removal mechanisms of algae cells and derived organic matter by independent UV, visible and infrared wave bands of PUV. The influence experiments using inorganic particle, natural organic matter and inorganic salt will be conducted, while the principal influence factors will be determined, which will provide useful information to improve the PUV performance. The computational fluid dynamics will be used to optimize the hydraulic distribution and irradiation density distribution in PUV device. All these studies will determine the intrinsic mathematic correlations among PUV wavelength, irradiation density and algae mortality, which will provide theoretical foundation for the application of PUV in algae-contained water pre-treatment.

紫外（UV）照射技术应用于高浊高有机物含藻水预处理的关键是克服传统汞灯的低穿透率、波长单一和藻类复活等问题。脉冲紫外（PUV）光源具有连续发射光谱和高穿透率，有望成为含藻水新型预处理方法。课题以单波长紫外发光二极管（UV-LED）结合复合表征方法从光合系统、酶系统和基因系统三方面研究UV破坏藻类细胞的分子机制，探索最佳杀藻波长-照射强度分布模式，优化选择PUV光源类型；采用滤光技术明确紫外、可见光和红外波段PUV照射对藻类细胞及其衍生有机物的去除机理；基于实际水体杂质成分特征，研究无机颗粒、天然有机物、无机盐等对PUV处理含藻水的影响，确定主要影响因子，寻求提高PUV处理效率的有效方法；基于机理研究，采用计算流体力学从水力分布和光强分布等方面优化设计PUV反应装置。通过本课题研究，阐明PUV波长分布、照射强度与藻类死亡率的内在数学关系等问题，为PUV在含藻水预处理的应用提供理论基础。

基于紫外（UV）的光氧化/光催化是广谱高效的高级氧化技术，能有效杀灭水中的微生物并降解有机污染物，在给水处理和污/废水处理领域有广阔的应用前景。紧凑、低能耗、环境友好的紫外发光二极管（UVLED）作为新型光源，成为光氧化/光催化研究领域的热点。项目首先以提高产毒水华藻类灭活效率为目标，系统考察了UV照射之后水华铜绿微囊藻（Microcystis aeruginosa）生物量的短期和长期变化，从细胞结构和光合量子产率确定M. aeruginosa的光合系统在不同单波长UVLED照射之后的受损情况，首次对光合量子产率和色素表达水平进行定量；发现铜绿微囊藻主要功能蛋白对280 nm的UV照射较为敏感，而DNA等遗传物质则对250 nm - 260 nm的UV照射的耐受力较弱，不同波长的UV照射均能损伤光合系统。以高效、节能、安全的去除水体中有机污染物为目标，分别研究UVLED/H2O2、UVLED/S2O82-和UVLED/TiO2耦合体系对微囊藻毒素、喹诺酮类抗生素和有机磷阻燃剂的降解过程，确定其降解效率和动力学；（1）采用UVLED结合H2O2降解藻毒素microcystin-LR (MC-LR)，发现单独UV照射并不能有效降解MC-LR，对于100 μg L-1的MC-LR，265 nm UV/H2O2能高效降解MC-LR，并削弱其毒性；（2）研究了UVLED/S2O82-体系降解环丙沙星（CIP）的动力学和效果，结果表明，不同UV波长（255-365 nm）能影响降解效率，对于3 μM的CIP，280 nm UV + 84 μM S2O82-的降解效率最高，速率常数kobs为0.1248 min-1；（3）研究了UVLED/TiO2体系降解磷酸三(2-氯乙基)酯（TCEP）的动力学和产物。结果表明，当[TCEP]0 = 3.0 μM，pH = 7.0，温度25 ± 2°C，[TiO2]0 = 50 μM时，254 nm UV/PS体系对TCEP降解速率常数kobs为0.1240 min-1；（4）以天然水体中多种污染成分，包括天然有机物和阴离子为影响因素，优化降解体系参数；采用高分辨质谱对降解产物分子进行精确定性和半定量研究，阐明其演化规律；（5）首次将基因组和蛋白质组表达用于降解产物毒理学评估，明确降解体系的环境安全性。