Experimental Research On The Removal Of Trace Phenolic Compounds From Water

Semiconductor photo-catalysts have attracted considerable attention in the field of environmental science due to their many significant advantages such as low consumption, mild reaction condition, simple operation and decrease of secondary pollution in photo-degradation of refractory organic pollutants including chlorophenol. When the semiconductor particle is illuminated by light having higher energy than its band gap energy, an electron is excited from the conduction band to valence band to reduce the molecule absorbed on the surface of the particle and the hole in valence band can act as an oxidant. ZnO is one of the most promising green catalysts due to its higher photo-degradation ability in decomposing of the organic pollutants into CO2, H2O and some mineral acid as well as its many advantages (i.e., safety, non-toxic nature, low cost and no pollution). In this thesis, ZnO nanoparticles were firstly prepared through the thermal alcoholysis reaction of zinc acetate in diethylene glycol (DEG). The effect of heating rate on the alcoholysis temperature was explored. The influences of seed solution amount added and reaction time on the surface morphologies of zinc oxide microspheres were also discussed.MBR process used in the treatment of drinking water is still a relatively new technology, which was first developed in the mid-1990s in France. Using MBR for trace 2,4,6-TCP removal in micro-polluted water sources has not been reported up to present. In this thesis, the experimental design used MBR as the main technology to address micro-polluted surface water to the reactor, adding PAC to strengthen the effect in the mean time. The purpose of this test is not only to remove the organic pollutants as a whole, but also to achieve effective removal of the trace 2,4,6-TCP compound at the same time during the stable operation of MBR. As a result, the treated water from MBR or MBR-PAC process could meet the requirements of Standards for drinking water quality (GB5749-2006).SPME is a new kind of micro-sample enrichment technology. In this thesis, the development of the technology of SPME coupled with HPLC, including the principle, the apparatus and its various applications, in the field of environment in recent years were reviewed. Through the preliminary study, the analysis methods under the optimized experimental conditions of SPME-HPLC were established for fast determination of trace phenolic compounds in micro-polluted lake water.