Laccase possesses a good degradation effect on organic pollutants,but it is too long to achieve the desired effect. In order to improve the treatment effect of laccase on degradation of organic pollutants,2,4-dichloro...Laccase possesses a good degradation effect on organic pollutants,but it is too long to achieve the desired effect. In order to improve the treatment effect of laccase on degradation of organic pollutants,2,4-dichlorophenol( 2, 4-DCP) was selected as a treatment target in the study. This study investigated a newtechnique for catalyzing the degradation of 2,4-DCP, that is,ultrasound-assisted laccase catalysis. The optimal experimental parameters such as p H,ultrasonic power,duty cycle and laccase concentration were determined under optimized experimental conditions. The results showed that the optimum conditions for degradation of 2,4-DCP were that pH = 5. 5,the input power was 105 W,the duty cycle was 50% and the laccase concentration was0. 4 U/m L. The degradation rate of 2,4-DCP reached 77. 5% under the optimum conditions at 4 h. When in ultrasonic environment,the enzymatic activity of laccase could be stimulated and improved.Compared with conventional methods,this technique significantly promoted the degradation rate of 2,4-DCP while reduced action time. Furthermore, no newpollutant was introduced into the degradation process. Therefore,ultrasound-assisted laccase catalysis is an environmentally friendly technique to degrade pollutants.展开更多
Phenolic compounds constitute one of the major pollutants in the modern world. Although many physical and chemical treatment technologies for their removal exist, most of them are economically not feasible. The presen...Phenolic compounds constitute one of the major pollutants in the modern world. Although many physical and chemical treatment technologies for their removal exist, most of them are economically not feasible. The present study was aimed at using silk cotton hull, a potent agricultural waste as an adsobent for removal of 2,4-dichlorophenol (2,4-DCP), which was used as a model phenolic compound. The process parameters were investigated and optimized conditions were determined. The equilibrium time was found to be 60 and 80 min for 10 and 20 mg/L and 100 min for 30 and 40 mg/L 2,4-DCP concentrations, respectively. Among the kinetic models applied, pseudo-second order model fitted well. The maximum adsorption capacity was 16.0 mg/g by Langmuir isotherm. Acidic pH was found favorable for the adsorption of 2,4-DCP. Studies on pH effect and desorption seemed to show that chemisorption played a major role in the adsorption process. In thermodynamic study, the change in entropy (△S 0) and heat of adsorption (△H0) of silk cotton hull carbon (SCHC) was estimated as 14.01 J/(mol·K) and 3.04 kJ/mol, respectively. SCHC as adsorbent for removal of 2,4-DCP from aqueous solution, is effective, inexpensive, indigenous, reusable, has low treatment time and is easily available in large quantities as waste there by significantly lowers the cost of wastewater treatment.展开更多
基金National Natural Science Foundation of China(No.41571306)the Project of Excellent Fund in Hubei Province,China(No.2018CFA067)Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources,China(No.2017zy003)
文摘Laccase possesses a good degradation effect on organic pollutants,but it is too long to achieve the desired effect. In order to improve the treatment effect of laccase on degradation of organic pollutants,2,4-dichlorophenol( 2, 4-DCP) was selected as a treatment target in the study. This study investigated a newtechnique for catalyzing the degradation of 2,4-DCP, that is,ultrasound-assisted laccase catalysis. The optimal experimental parameters such as p H,ultrasonic power,duty cycle and laccase concentration were determined under optimized experimental conditions. The results showed that the optimum conditions for degradation of 2,4-DCP were that pH = 5. 5,the input power was 105 W,the duty cycle was 50% and the laccase concentration was0. 4 U/m L. The degradation rate of 2,4-DCP reached 77. 5% under the optimum conditions at 4 h. When in ultrasonic environment,the enzymatic activity of laccase could be stimulated and improved.Compared with conventional methods,this technique significantly promoted the degradation rate of 2,4-DCP while reduced action time. Furthermore, no newpollutant was introduced into the degradation process. Therefore,ultrasound-assisted laccase catalysis is an environmentally friendly technique to degrade pollutants.
基金the Chonbuk National Uni-versity Post-Doctoral Program (2006)Research Centerfor Industrial Development of Biofood Materials in the Chonbuk National University, Chonju, KoreaThe centeris designated as a Regional Research Center appointed by the Korea Science and Engineering Foundation (KOSEF),Jeollabuk-do Provincial Government and Chonbuk Nation-al University
文摘Phenolic compounds constitute one of the major pollutants in the modern world. Although many physical and chemical treatment technologies for their removal exist, most of them are economically not feasible. The present study was aimed at using silk cotton hull, a potent agricultural waste as an adsobent for removal of 2,4-dichlorophenol (2,4-DCP), which was used as a model phenolic compound. The process parameters were investigated and optimized conditions were determined. The equilibrium time was found to be 60 and 80 min for 10 and 20 mg/L and 100 min for 30 and 40 mg/L 2,4-DCP concentrations, respectively. Among the kinetic models applied, pseudo-second order model fitted well. The maximum adsorption capacity was 16.0 mg/g by Langmuir isotherm. Acidic pH was found favorable for the adsorption of 2,4-DCP. Studies on pH effect and desorption seemed to show that chemisorption played a major role in the adsorption process. In thermodynamic study, the change in entropy (△S 0) and heat of adsorption (△H0) of silk cotton hull carbon (SCHC) was estimated as 14.01 J/(mol·K) and 3.04 kJ/mol, respectively. SCHC as adsorbent for removal of 2,4-DCP from aqueous solution, is effective, inexpensive, indigenous, reusable, has low treatment time and is easily available in large quantities as waste there by significantly lowers the cost of wastewater treatment.
