大气压纳秒脉冲气-液弥散放电等离子体饮用水杀菌中OH等活性物种诊断研究

There is existing an enormous threat when the sources of drinking water are invaded by harmful microorganism such as bacteria and unicellular algae. Since there are some drawbacks existing in the traditional water sterilization technology, e.g. breeding of chlorine-resistant algae, secondary pollution of water supply system, and the residual chlorine and its metabolites endanger human health. A more safety sterilization technology is needed to developing for the safety of drinking water. In this project, based on the applications of atmospheric pressure nanosecond pulsed gas-liquid diffuse discharge in sterilization. Optical emission spectra, cavity ring-down spectroscopy, and absorption spectra etc. are employed to diagnosis the active species (OH, O, HO2 etc.) quantitatively. The temporal distribution of short lifetime active species e.g. OH can be obtain and the spatial distribution of long lifetime active species e.g. O3 can be determined. The effects of pulse polarity, electrode configuration, working gas, pulse peak voltage and pulse repetition rate on the concentrations of active species will be studied. To determined the inactivation mechanism of gas-liquid discharge to the microorganism such as escherichia coli, blue-green algae etc., a quantitative- semiquantitative model of active species in gas-liquid discharge system will be developed and the main physicochemical processes involved will be discussed. From the investigation in this project, theoretical reference and technical guidance would be provided to the technologies of safety water disinfection and eutrophication control.

饮用水源受有害菌类、藻类污染时会严重危害人体健康，传统杀菌技术仍存在耐氯藻类滋生、供水系统二次污染、自来水中余氯代谢物影响人体健康等问题，迫切需要寻求一种新的饮用水消毒技术以提高饮用水安全水平。本项目拟采用大气压纳秒脉冲气-液弥散放电等离子体应用于饮用水杀菌。利用发射光谱、光腔衰荡光谱和吸收光谱技术对可与微生物作用的OH、O等活性物种进行定量诊断研究，获得OH等短寿命活性物种的浓度随时间演化过程和O3等长寿命活性物种在气液体系中的分布，研究活性物种浓度及其时空分布特性随脉冲电压、电极结构、工作气体组分、脉冲峰值电压等参数的变化规律，建立气-液放电体系活性物种定量-半定量模型，确定气-液弥散放电等离子体中活性粒子参与的主要物理化学过程和向液体传质方式，对饮用水中常见的大肠杆菌、蓝藻等有害微生物的杀菌机理进行深入细致的研究，为饮用水安全消毒技术提供重要理论依据和技术指导。

针对项目立项时提及的现有饮用水杀菌技术存在耐氯藻类滋生、供水系统二次污染、自来水中余氯影响人体健康等问题，本项目旨在从机理上研究等离子体杀菌消毒技术的若干重要问题，推动气液放电等离子体技术的应用，并以此为提高应用水的安全问题。通过采用纳秒脉冲激励，本项目在针-板、针管阵列-板、鼓泡等多种电极结构下实现了稳定的弥散气液放电等离子体，并对等离子体的时空分布特性和杀菌机制进行了理论和实验研究。项目中采用高时空发射光谱技术，研究了等离子体中的能量驰豫过程和活性物种的产生机制。在逐步深入研究气液放电特性、气液放电杀菌机制、气液放电活性物种分布及活性物种传质等关键问题的过程中，项目还采用了建立活性物种0维动力学模型，对等离子体中OH、O、H等短寿命的活性物种的动力学过程和O3、H2O2等长寿命活性物种的产生机理进行了理论研究，并对其反应机制进行了探讨。此外，项目还研究了脉冲峰值电压、脉冲重复频率、电极结构等参数对等离子体活性物种浓度、分布、杀菌效率的变化规律，研究了液体中存在的主要活性成分，并探讨了纳秒脉冲放电等离子体中活性物种在两相界面的输运机制和对微生物的作用机制，顺利的完成了本项目的研究目标。