Study On White-rot Fungi Degradation And Adsorption Of Carbon Tetrachloride And Trichloroethylene

With the development of industry and agriculture, all over the world frequently detected carbon tetrachloride(CT), trichloroethylene(TCE) that has three causes harm of chlorinated hydrocarbon organic matter in groundwater. As a result of the degradation of white-rot fungi ability has a broad-spectrum efficiency. In this paper, preliminary studied the biodegradation characteristics of white rot fungi, using lignin degrading enzymes(Li P,Mn P) produced by white-rot fungus on CT, TCE biodegradation, different conditions was studied for the influence of white-rot fungi degradation of chlorinated hydrocarbons, determine the best degradation conditions;Studied the adsorption performance of the inactivated bacteria on CT and TCEand its dynamics, thermodynamics, find its degradation, adsorption efficiency and rules.The main results are as follows:1. Selected several kinds of chlorinated hydrocarbons thatare harmful in the groundwater, such as dichloromethane, trichloromethane, dichloroethylene, TCE, CT, grow in the same environment conditions for 7 d degradation experiment, the results show that the white-rot fungi to CT, TCE both chlorinated hydrocarbon degradation rate is higher, at 58.9% and 36.9%respectively.2. In the process of white-rot fungi degradation of CT to determine enzyme activity, and considering the final degradation rate of CT.Results show that the best conditions that the white-rot fungus growth and enzyme production is for nitrogen limitation. Bacteria make carrier for immobilized culture with stainless steel net, at the same time in 110 m L of system and culture medium for 25 m L, white-rot fungi dissolved oxygen is relatively abundant, grows the best effect, under the condition of the degradation effect of CT is the best, the degradation rate of 65.8%.3. According to the environmental conditions of white-rot fungi degradation of CT,through the experiment of single factor optimization. The results show that the best condition of White-rot fungi to degrade CT is p H=4.5, table temperature 35℃, initial concentration of CT is 120 μg/L, table speed is 150 rpm/min, the spore suspension dosing quantity is 1 m L/100 m L, the degradation rate was 87.7%. Degradation process in line with the first order kinetics, biological degradation reaction kinetics model ofln C=-0.3025t+5.052.4. According to the environmental conditions of white-rot fungi degradation of CT,through the experiment of single factor optimization. The results show that the best condition of White-rot fungi to degrade TCE is p H=4.5, table temperature 35℃, initial concentration of TCE is 1mg/L, the table speed 150 r/min, the spore suspension dosing quantity is 1 m L/100 m L, the degradation rate was 56.1%.Degradationprocess in line with the first order kinetics, biodegradation reaction kinetics model of ln C = 0.0747t-0.04.5. The process that with inactivated bacteria of white-rot fungi adsorbs CT and TCE in line with the Langmuir adsorption isotherm models, adsorption kinetics is in line with pseudo secondary model. According to thermodynamics △G<0, △H<0, △S<0. So the adsorption reaction is spontaneous physical adsorption process, and gives off heat, the entropy decreases in the process.