摘    要：环境污染问题己经成为当前中国发展中的一个重大问题，水质的污染是环境污染的一大方面，污水是否达到排放标准由污水的污染指数决定，其中最重要的指标是污水的化学需氧量(COD)值。 纳米Ti02光催化作为一种高级氧化技术可将水中有机污染物完全光催化降解为H20和CO2，因此光催化在有机污染物降解方面具有降解效率高、无二次污染等优点而受到人们的广泛关注，在环境监测方面显示出广阔的应用前景。本文采用纳米二氧化钛粉末涂覆法制备纳米TiO2微流控芯片，并以UV-LED为光源，制备光催化微反应器，并采用在线检测的方式进行吸光度测定。以K2Cr2O7为光催化氧化剂，在光强为80 mw/cm2时，最佳的COD降解条件为：K2Cr2O7浓度0.125mol/L，H2SO4浓度0. 2mol/L，流速为400μL/h，温度为35℃。在该条件下COD线性范围为100-1200mg/L，其检出限约为32mg/L，完成一次样品测试时间仅为15-20分钟。

Abstract：The problem of environmental pollution has become a major problem in the current development of China. The pollution of water quality is a major aspect of environmental pollution. Whether the sewage meets the discharge standard is determined by the pollution index of the sewage.One of the most important indicators is the chemical oxygen demand (COD) of sewage.As an advanced oxidation technology, nanometer TiO2 photocatalysis can completely degrade organic pollutants into H2O and CO2 in water, so photocatalysis has high degradation efficiency in organic pollutants degradation.Due to the advantages of no secondary pollution and so on, people pay more attention to it, and it has a broad application prospect in the field of environmental monitoring.In this paper, nanometer TiO2 microfluidic chips were prepared by nano-TiO2 powder coating, and photocatalytic microreactors were prepared using UV-LED as light source,and the absorbance was determined by on-line detection.Using K2Cr2O7 as photocatalytic oxidant, the optimal degradation conditions of COD were as follows: 0.125mol/L K2Cr2O7 and 0.2mol/L H2SO4 at the temperature of 35℃ and the light intensity of 80MW/cm2and the velocity is 400μL/h.Under this condition, the linear range of COD is 100-1200mg/L,the detection limit is about 32mg/L. The test time for one sample is about 10-20 minutes.

关键词：纳米二氧化钛；微流控芯片； 光催化降解； COD在线检测

Keyword: nano-titanium dioxide; microfluidic chip; photocatalytic decomposition;  COD on-line detection

目    录

1. 前言 4

2. 实验部分 5

2.1仪器与试剂 5

2.1.1仪器 5

2.1.2试剂 6

2.2实验步骤 6

2.2.1备用母液的配置 6

2.2.2微流控芯片中二氧化钛涂层制备 6

2.2.3光催化反应装置及流程 7

2.2.4最佳反应条件的确定 7

3.结果与讨论 7

3.1光催化微反应器中COD测定原理 7

3.2光催化降解条件的影响 9

3.2.1光照强度的影响 9

3.2.2注射泵流速的影响 10

3.2.3重铬酸钾浓度的影响 10

3.2.4硫酸浓度的影响 11

3.2.5反应温度的影响 12

3.3COD标准曲线