Study On The Degradation Of Pyridine Containing Wastewater By Fenton/Ultrasonic Advanced Oxidation Method

Pyridine is an important chemical raw material,as one of the most common nitrogen heterocyclic compounds.It is widely used in chemical industry,coking industry,agriculture and pharmaceutical industry.In recent years,with the rapid development of economy and science technology,the demand for pyridine in industry is increasing gradually,and the content of pyridine wastewater is increasing.Therefore,how to effectively control the emission of pyridine-containing organics is attracting more and more attention.It is very important to find a highly efficient and environmentally friendly technology for treating containing pyridine wastewater,which is very important to the treatment of industrial wastewater.This paper uses headspace-gas chromatography for the determination of pyridine concentration.,the effects of standard sample pH,NaCl dosage,headspace equilibrium temperature and time on peak area determination of pyridine were discussed,the accuracy of pyridine concentration determination by headspace-gas chromatography was investigated.;using Fenton method,ultrasonic method and the combination method of Fenton/ultrasonic degradation of pyridine wastewater,and by analyzing the impact factors of the initial p H value,H₂O₂ concentration,FeSO₄·7H₂O,ultrasonic power and initial concentration of solution,the corresponding dynamics model was established,discusses the influencing factors on the degradation of pyridine.Finally,the feasibility of using Fenton/Ultrasonics to treat actual wastewater was investigated using the pyridine-containing wastewater discharged from the chemical plant's workshop as a treatment target..The main results are as follows:The pyridine concentration was analyzed by headspace gas chromatography?GC?.Through the single factor experiment and orthogonal experiment,it is found that:in the standard sample pH value was 9,the NaCl dosage was 350g/L,the equilibrium temperature was 85?,the equilibrium time was 40min,the standard sample of pyridine for determination of the peak area;The influence of various factors on the peak area of pyridine determination is:standard the sample pH value>the equilibrium temperature>the equilibrium time>NaCl dosage;headspace gas chromatography sensitivity analysis of concentrations of pyridine was2518.7,the detection limit was 0.0012mg/L,the relative error was 1.2%².4%,the recovery rate was 93.0%¹06.0%,this method has good accuracy.Degradation of pyridine analogue wastewater by Fenton method,through the influence factors and reaction kinetics analysis found:the reaction of Fenton degrading pyridine solution accords with the first-order reaction kinetics;The optimum process parameters for degrading pyridine solution by Fenton method ware the initial pH value was 3,the concentration of H₂O₂ was 40mmol/L,the concentration of FeSO₄·7H₂O was 0.617g/L;in this condition,the kinetic constant K of pyridine solution degradation was the largest,the degradation rate of pyridine solution with an initial concentration of 100 mg/L was 56.0%and the K value was 0.0040 min^-1;the degradation effect of pyridine solution and K value decreased with the increase of initial concentration;through orthogonal experiment,the influence degree of each influencing factor is:H₂O₂ concentration>initial pH value>pyridine initial concentration>FeSO₄·7H₂O concentration.The ultrasonic method is used to degrade the simulated wastewater of pyridine.The results showed that the ultrasonic degradation of pyridine solution reaction follows first order reaction kinetics;the initial pH value was 11,the ultrasonic power was 400W,the best effect of degradation of pyridine,pyridine solution degradation reaction rate constant K maximum;the degradation rate of pyridine solution with initial concentration of 100mg/L was 56%,the K value was 0.0052min^-1;K value decreased with the increase of initial concentration;through orthogonal experiment found that,when the initial pH was 11,the ultrasonic degradation of pyridine between 320W and 480W is better,the influence degree of each influencing factor was:initial p H value>initial concentration of pyridine>ultrasonic power.The effect of three Fenton/ultrasonic combination schemes on the degradation of pyridine simulated wastewater was studied.,found that three schemes of pyridine reaction were consistent with first-order kinetics;the best degradation of pyridine solution is running ultrasonic 90min after Fenton 60min,the rate constant K of pyridine solution degradation is the largest,under the optimum conditions,the degradation rate of pyridine solution reaches80.2%,the K value was 0.0112min^-1;the effect of three combinations on the degradation of pyridine solution is ranked by:first Fenton after ultrasonic method>first ultrasonic after Fenton method>Fenton/ultrasonic method;the optimum process parameters of Fenton/ultraso-nic synergetic degradation of pyridine solution was:the initial pH value was 11,the ultrasonic power was 400W,the concentration of H₂O₂ was 40mmol/L,the concentration of FeSO₄·7H₂O was 0.357g/L,and when the initial concentration of pyridine solution was350mg/L,the degradation rate was 35.1%,K value was 0.0029min^-1.First Fenton after ultrasonic method treatment of wastewater discharged from chemical plant.The study found that:according to the optimum parameters of simulated wastewater,Fenton process parameters:pH value was 3,dosage of FeSO₄·7H₂O was 0.60g/gCOD_cr,dosage of H₂O₂ was 39.0mmol/gCOD_cr;the ultrasonic parameters:the initial pH value was 11,the ultrasonic power was 1300W/gCOD_cr,when the wastewater CODcr concentration was1000mg/L,the removal rate of COD_cr 32.1%,the BOD₅/COD_cr of the wastewater increased from 0.26 to 0.52,which shows that the method can effectively improve the biodegradability of wastewater.