| It is well known that water is one of the most abundant resources on the earth. Butthe available water resource quantity is scarce, and water resources pollution leads tothe grim situation of water environment with the development of economy.Therefore,the degradation of poisonous and harmful substances in the water has become a hotsocial concern to all mankind.The chloride ion selective electrode method and gas chromatography method wereadopted and were compared in this paper. The influence of iron on degradation ofchloroform was studied. Energy-saving and environmental protection natural lightwas selected as light source. And the homemade titanium dioxide was selected as rawmaterial, then loaded on the perlite, at the same time joining the zero-valent ironwhich made titanium dioxide absorption spectrum redshift.And the adsorption abilityof activated carbon was used, so that it can increase the local concentration ofchloroform for removing trace of chloroform in distilled water. The influence rules ofphotocatalytic effect of trace chloroform in water with the different particle size anddosing quantity of zero-valent iron, the different particle size and dosing quantity oftitanium dioxide,the different amount of additive activated carbon were studied andthe optimum parameters were obtained. On this basis, orthogonal table was designedand orthogonal experiments were conducted to get the best combination of theremoval of chloroform. Four models (L-H order reaction, zero order reaction, firstorder reaction, secondary reaction)were used to do the curve fitting and analysis withthe different particle size and dosing quantity of zero-valent iron, the different particlesize and dosing quantity of titanium dioxide, the different amount of additiveactivated carbon, pH and the initial concentration of chloroform. Conclusions are asfollows:1. Two analysis methods （the chloride ion selective electrode and gas phasechromatography）were adopted, the influence on the reaction with the differentdosing quantity of iron were respectively studied to get the same conclusion.It is thatTHMS removal rate first increases and then decreases with the increment ofzero-valent iron dosing and the best fittings are the secondary reaction.The removalrate of150mg/L THMS which was removed by100mesh8g zero-valent iron is23.6%, The removal rate of low concentration of chloroform in distilled water whichwas removed by100mesh0.075g zero-valent iron is37.4%.2. The influence rules of the degradation of chloroform with the different particlesize and dosing quantity of zero-valent iron, the different particle size and dosingquantity of titanium dioxide,the different amount of additive activated carbon werestudied. On this basis, the orthogonal experiment was designed.It is concluded that the primary and secondary order of the influencing factors are the concentration of CHCl3,the amount of activated carbon, titanium dioxide and zero-valent iron consumption.The best combination is0.095g zero-valent iron,0.08g titanium dioxide,2g activatedcarbon,36.39μg/L the solution of CHCl3. And the best removal efficiency ofchloroform is88.6%.3. The removal rate of chloroform with titanium dioxide loaded on activated carbonis obviously lower than that of chloroform with the titanium dioxide loaded on theperlite.And titanium dioxide can be motivated to produce optical cavity electron pairfor degradation of chloroform in the sun. THMS removal rate in the sun is18.62%higher than in the dark condition. And the light absorption area of titanium dioxideunder the condition of the zero-valent iron auxiliary catalyst significantly wasincreased. The absorption area of loaded type of TiO2reacted with zero-valent ironwas increased by45.3%than that of loaded type of TiO2reacted without zero-valentiron.There was any other light sources in the experiment, and the cheap iron wasmade full use to achieve the purpose of saving energy. |
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