香港的环境保护与管理

香港的环境保护与管理香港理工大学土木与结构工程系李湘中，赵玉光香港作为一个拥有６００多万人口的城市，与世界各大都市一样，城市环境承受的压力十分巨大。其环境压力主要来自市民，以及他们在家中、工作场所与消遣场所的活动。一个地方聚居的人口越多，工商业活动越...     

煮沸对自来水中氯仿含量的影响

为了解管网末梢自来水及其在加热煮沸过程中致癌有机物——氯仿（CHCl3）含量的变化，采用不同的加热器、运用不同的加热方式对我国南方某地区管网末梢的自来水进行了加热煮沸处理，并对不同加热煮沸时间的水样进行了色质联机分析。结果发现，氯仿含量与热水器的功率、加热煮沸的方式及水中自由余氯含量均有关系。不管采用何种原水、何种加热器和加热方式，若煮沸后使水保持数分钟的沸腾状态均可使水中的氯仿含量降低到5μg／L以下的安全水平。     

光敏氧化法处理苯酚废水的试验研究

本文通过实验和理论分析,研究了苯酚光敏氧化法的基本规律,确定了反应的必要条件和苯酚经光敏氧化反应后的产物,给出了该反应的动力学模式。试验结果表明,影响反应速度的主要因素是光照强度、光敏剂浓度和pH值,而且存在一最佳光敏剂投加量。最后,通过对焦化厂含酚废水进行光敏氧化处理的初步试验,探讨了该方法用于工程实际的可能性和适用条件,可为低浓度含酚废水的处理提供一种新途径。     

高铁酸盐去除水中氯酚类化合物研究

以3种氯代酚:4-氯苯酚(CP)、2,4-二氯苯酚(DCP)、2,4,6-三氯苯酚(TCP)为代表性有机物,对比研究了高铁酸盐(FeO42-)对各种有机污染物的去除及影响因素.结果表明,氯酚类化合物的去除直接受溶液pH影响,并且这些有机物去除的最佳pH范围与其pKa具有相关性.对于每种氯酚类化合物,pHpKa时,反应主要受高铁酸盐氧化还原电位的影响.随着氯酚类化合物取代氯原子数的增加,其非离解态化合物与高铁酸盐的反应活性增加,而离解态化合物与高铁酸盐反应活性随取代氯原子数的增加而降低.     

Effect of surface state properties of modified TiO2 powders on their photo—catalytic activity

With an attempt to investigate the effect of impurity and tungstem oxide on the recombination and separation of electron-hole pairs,and disclose the effect of surface state on the photo-catalytic activity of TiO2,an innovative photo-catalyst 3%WO3/0.5%Au^3 /AiO3 was prepared by means of sol-el method.The photo-oxidation efficiency of photo-catalyst was evaluated by conducting a set of experiments to photo-degraeds methylene blut(MB)in aqueous solution.The surface state properties were examined by means of surface photovoltage spectra(SPS)and electron-field-induced SPS(EFISPS).The experiments demonstrate that the strongest peak is attributed to electron excited from valence band to conduction band and the second strongest peak is attributed to electron excited from valence band to oxygen molecular for all samples,Electron is trapped by O2 absorbed on the surface of TiO2.And the surface state of O2^- forms.For(1%,3%)Au^3 /TiO2 sample,two new peaks that significantly present at 414nm and 400nm respectively should be attributable to gold impurity energy level.And for tungsten oxides doping samples,4 peaks that significantly present in the region of 500-800nm should be attributable to tungstem impurity energy level.The intensity of EFISPS decreases with increasing the content of gold ion or tungsten oxide when its content is no more than their optimal dosage.However,when the content of gold ion or tungsten oxide is more than their optimal dosage,impurity energy level becomes recombination center from separation center and the intensity of all peaks increases for them.     

网状TiO2/Ti电极的制备及染料的光电催化降解

用阳极氧化法制备出一种新型光电极－网状TiO2/Ti电极，用扫描电镜和拉曼光谱对电极表面TiO2膜的形貌和晶体结构检测。结果表明：膜的结构和性能受阳极氧化过程中氧化速度的影响；在控制实验条件下，锐钛型TiO2是其主要结晶形态。染料若丹明B的光电催化降解和光催化降解的实验结果表明：外加偏压可以有效地提高有机物的光催化降解效率。TOC的测定结果显示，在光电催化氧化过程中，若丹明B几乎完全矿化。     

Photoelectrocatalytic properties and reactivity of Ti/Au-TiO2 mesh electrodes

A kind of photoelectrode was innovated by anodising titanium mesh in H2SO4 solution and photo-reduced in HAuCl4 solution and named Ti/Au-TiO2 mesh electrode.The structural and surface morphology of the Ti/Au-TiO2 mesh was examined by X-ray diffraction,laser Raman spectra,scanning electronic microscopy(SEM) and X-ray photoelectron spectroscopy respectively.The results indicate that its crystal structure,morphology and the size of pore are affected greatly by gold deposition.XPS measurement show that the valence band of Ti/TiO2 has two peaks:a wide one at 4.97eV and a narrow one at 6.61eV,which correspond mainly to π(nonbonding)and σ(bonding)O 2p orbitals,The emission intensity of O 2p orbitals becomes stronger and the width of the valence band increases with the increase of Au content.And the emission of nonbonding shifts toward lower binding energy and that of bonding O 2p orbitals shifts toward higher binding energy.The photoelectrocatalytic(PEC) oxidation of humic acid( HA) was investigated in terms of TOC.The PEC oxidation efficiency of Ti/Au-TiO2 mesh with optimal content of gold is higher than that of Ti/TiO2 mesh.It is suggested that the recombination of electrons and holes is hindered owing to gold deposition.The investigation shows that PEC oxidation is a convenient way to mineralize organic matter for water treatment.