Investigation On Several Kinds Of Carbon Nanotubes Under Microwave Irradiation Catalytic Degradation Of Organic Pollutants In Aqueous Solution

Organic pollutants in water and wastewater have brought great harm to the ecosystem and human health, MW catalytic oxidation technology has been exploited as a powerful tool in the degradation of organic pollutants. Carbon nanotubes with one-dimensional, hollow and tubular structures, because of huge specific surface area and excellent microwave absorbing properties, which can degrade organic pollutants under the microwave irradiation. Furthermore, by improving catalyst, ferrite supported on carbon nanotubes under microwave irradiation, in order to improve the degradation efficiency of organic pollutants. Also, Comparison catalytic activity of microwave induced three kinds of different ferrite supported CNTs.The technology of microwave induced carbon nanotubes(MW/CNTs) catalysis degradation was developed and applied in the treatment of azo dyes in the aqueous solution. The catalysis activity of the CNTs with different sizes was compared. Using the 10-20 nm, 20-40 nm, 40-60 nm CNTs/MW technology, When adding 1.2 g/L of carbon nanotubes with 25 m L, 25 mg/L methyl orange under microwave irradiation time 3 min, microwave power 450 W reaction conditions, the degradation rates of three kinds of particle size of 10-20 nm, 20-40 nm, 40-60 nm CNTs were 89.2%, 70.8% and 62.9%. The effects of some factors such as MW irradiation time, MW power, MO initial concentration, catalyst dose, MO initial p H and used times of CNTs on the degradation were discussed in detail. The results showed that carbon nanotubes can be effectively combined with microwave in treatment of azo dyestuff in aqueous solution. Also, the 10-20 nm CNTs powder revealed the highest catalytic activity of the three CNTs with different sizes under MW irradiation.We studied that zinc ferrite supported on carbon nanotubes(Zn Fe2O4/CNTs) under microwave irradiation degraded endocrine disruptor Bisphenol A. Zinc ferrite supported on carbon nanotubes was synthesized using microwave hydrothermal method. Under the catalyst preparation conditions applied of Fe3+ concentration 0.03mol/l, M-H pressure 1.5 M, M-H time 30 min, precursor p H 9.5, When adding 0.8 g/L Zn Fe2O4/CNTs and 25 m L, 10 mg/L Bisphenol A under microwave irradiation time 2 min, power 750 W reaction condition, the degradation rate was up to 62.33%. Under the same degradation conditions, the rate of degradation of CNTs/MW system was slightly smaller, 47.67%. Therefore, comparing the catalytic activity, Zn Fe2O4/CNTs under microwave irradiation was higher than the pure CNTs.We compared the catalytic activity of three kinds of ferrite supported on carbon nanotubes(Zn Fe2O4/CNTs, Co Fe2O4/CNTs, Ni Fe2O4/CNTs), we chose synthesis method was the microwave hydrothermal method. Discussing the process of preparation of catalyst, Fe3+ concentration, microwave hydrothermal pressure, microwave hydrothermal time, precursor acidity. When the synthetic conditions of the catalyst Fe3+ concentration 0.03mol/l, M-H pressure 1.5 M, M-H 30 min, the acidity 9.5, microwave irradiation time 4 min, power 750 W, adding 0.4 g/L ferrite/CNTs, three catalytic Zn Fe2O4/CNTs, Co Fe2O4/CNTs, Ni Fe2O4/CNTs decomposed the 25 ml 10 mg/L methyl parathion, the degradation rates respectively were 95.79%, 91.48% and 100%. Because of the structure difference of the synthesis composite materials, the order of three kinds of ferrite on the degradation of methyl parathion is Ni Fe2O4/CNTs > Zn Fe2O4/CNTs> Co Fe2O4/CNTs.In summary, Carbon nanotubes had microwave catalytic activity. the Zn Fe2O4/CNTs combined with microwave catalytic degradation technology could effectively destroy the organic pollutants resulted in completely decomposing. The Zn Fe2O4/CNTs displayed higher catalytic activity than CNTs under MW irradiation. Also, compared the removal effect of three kinds of ferrite supported on carbon nanotubes, the Ni Fe2O4/CNTs powder revealed higher catalytic activity than Zn Fe2O4/CNTs and Co Fe2O4/CNTs under MW irradiation. The integrated MW/CNTs technology displayed plenty of advantages such as high degradation efficiency, short MW irradiation time, simple, rapid and no residual intermediates. Thus, this technology showed to be prospective for the decomposition of organic pollutants in wastewater treatment applications.