Degradation Of Paracetamol In Aqueous Solution By The High-voltage Discharge Plasma And Carbon Nanotubes

As a common antipyretic analgesic medicine,paracetamol is the important raw materials for the synthesis of pharmaceutics.It is also one of the largest pharmaceutical raw materials in china.With the increase of consumption of pharmaceutics and personal care products(PPCP),and the discharge of pharmaceutical wastewater,paracetamol has been detected in surface water.Acetaminophen in the environment can cause genetic toxicity,liver toxicity,endocrine interference and other negative effects.Therefore,in order to guarantee the drinking water safety,it is of great significance to develop the efficient technology for removal of paracetamol.The traditional methods for paracetamol removal from water included particle/powder activated carbon adsorption,biodegradation and oxidation(03,H202,C1O-etc.).In recent years,carbon nanotubes arose people’s attention,which provided a new one-dimensional nano material of adsorbents and catalysts.Some scholars tried to use carbon nanotubes as adsorbent to enrich the trace paracetamol,and successfully detected the trace paracetamol in water.In addition,the development of low temperature plasma oxidation technology also provides a more efficient method to degrade organic pollutants in water.Therefore,it is expected that use the combination of carbon nanotube adsorption and low temperature plasma oxidation for removal of paracetamol in water.By this method paracetamol could be removed by adsorption ana oxiaation rrom water,ana the carpon nanotube couia pe aiso regeneratea on-site.Based on the above research background and previous work,we select paracetamol as target pollutant,and comparative study on the carbon nanotube adsorption,plasma oxidation,the combination of carbon nanotube adsorption and low temperature plasma oxidation for the removal of paracetamol.The conclusions were shown as follows:1)Low temperature plasma could degrade the paracetamol because that the air will be ionized,and formed a large number of high energy electron,·OH,·O,H02-and other free radicals with strong oxidation.These strong oxidation substances could degrade paracetmol into small molecular organic compounds.The initial concentration of solution,output power,gas flow rate and pH had significant effect on the degradation rate of paracetamol,.2)Carbon nanotubes can adsorb acetaminophen from simulated wastewater of,and the equilibrium adsorption capacity was about 85.1mg/g.The adsorption isotherms could be well fitted by Langmuir equation indicating a monolayer adsorption model.Furthermore,the adsorption kinetics process could be fitted by the pseudo-second-order kinetic modelL and the adsorption rate was controlled by the intra-particle diffusion.3)The removal rate of paracetamol by adsorption,low temperature plasma and the combination of adsorption and low temperature plasma-plasma were 70%,82.1%and 98%,respectively.The removal rate of paracetamol by adsorption and discharge was significantly higher than that of single adsorption and low temperature plasma oxidation.This could be explained as follows:1)carbon nanotube could not only adsorbe paracetamol but also increase the degradation rate of paracetamol by low temperature plasma;2)low temperature plasma could not only degrade the paracetamol but also regenerate the carbon nanotube on-site.