Study On The Applications Of Carbon Nanotubes In The Organophosphorus Pesticide Residues Analysis And The Adsorption And Degradation Behavior Of Triazophos

China is a large agricultural nation whit a tremendous amount of pesticides thathanve been used every year. Pesticide plays an indelible effect in the prevention ofcrops from disease or insect in the increasement in production. The long-term andextensive use of pesticides caused the problem of pesticide residue and creating agreat threat for environment and food safety. Then it is urgent and necessary whichfinding a analysis of rapid and accurate detection of pesticide residues forencironmental samples. Pesticide in the soil and water environment, most of themcould be adsorbed by soil or the sediment. There are some intermediate productsgenerate and final products are ingorganic substances during the transformatin anddegradation. The environmental behavior of pesticide have a direct influence on theresidual property. In order to evaluate the persistence of pesticides in soil and waterenvironment, not only detect pesticide residues in soil and water environment, but tostudy its environmental behavior. In this paper, detecting the three organophosphoruspesticides in water and soil is based on the multi walled carbon nanotubes as solidphase extraction packing. And using carbon nanotubes as an adsorbent to adsorbtriazophos in water environment, the result shown that adsorption of carbonnanotubes are superiority as the filler. Meanwhile, using soil as an adsorbent toadsorb triazophos in water environment, study on hydrolysis and photolysis oftriazophos behavior, which can offer necessary data for a whole environmentalassessment of triazophos.The main content in this paper includes the following parts:(1)To establish a method to determine chlorpyrifos, profenofos and triazophospesticide residues in water environment by gas chromatographic with MWNTs assolid phase extraction material.The results showed that: 3 kinds of organophosphatepesticide at concentrations of 0.005 ~ 1.0 mg/L linear relationship was good, thecorrelation coefficient was greater than 0.9993, the detection limit of the method in2.69 × 10-4~ 7.43 × 10-4mg/L. Applyed this method to the actual samples anddetermined the recovery rate. The recovery of different levels(0.005,0.01,0.05 mg/L)were between 72.3%~116.7%, the RSD value was less than 13.6%. MWNTs hasbetter purification effect on water samples, this method was applyed in detectedchlorpyrifos, profenofos and triazophos pesticide residues in water environment.(2)A multi-residue analysis method based on solid phase extraction withMWCNTs as adsorbent was developed. The detection of chlorpyrifos, profenofos andtriazophos pesticide residues in soil was carried out by gas chromatography.Theexperiment results suggest that 3 kinds of organophosphate pesticide atconcentrations of 0.01 ~ 1.00 mg/L linear relationship was good, the correlationcoefficient was greater than 0.9996, the detection limit of the method in 1.78×10-3~4.41×10-3 mg/kg. Applied this method to the actual samples testing and determinedthe recovery rate. The recovery of different levels(0.05、0.1、0.5 mg/kg) were between85.9%~118.7%, the RSD value was less than 10.7%.It shown that the method wasapplicable to detected chlorpyrifos, profenofos and triazophos pesticide residues insoil.(3) Using MWCNTs as adsorbent study on the adsorption properties fortriazophos in water environment, the influence of adsorption performance on theMWCNTs dosage, p H, time, ion strength were investigated. And related adsorptionkinetics, adsorption thermodynamic model fitting. It was found that apseudo-second-order equation(r>0.9972) and the Freundlich equation(r>0.9597)provided the best correlation to the adsorption process.(4) It was studied that the absorption behavior that the soil adsorbed triazophosin water environment.And the influence of adsorbents dosage for adsorptionperformance, p H, ion strength were investigated.Then related adsorption kinetics,adsorption thermodynamic model fitting. Based on this, speculate the processes andnature that soil adsorbed triazophos in water environment, then the adsorptionmechanism was discussed. In the meantime, the effect of different soil, pesticidenature, pesticides combined of the adsorption process were inspected. The resultsshowed that content of soil organic matter and the nature of pesticide are the maininfluence factors.The coexistence of chlorpyrifos and profenofos effects on the soiladsorbed triazophos, its adsorption behavior and monomer triazophos have significnatdifference.(5)The study examines the hydrolysis character of triazophos under differentPH and initial concentrations at room temperature. And studied the triazophoshydrolysis and photolysis character when some pesticide coexistence. The experimentresults indicated that the triazophos hydrolysis was visibly influenced by change theconcentration and p H and its hydrolysis and photolysis are conformity with the firstorder kinetics equation. Moreover, the rate of hydrolysis is increased and its rate ofhydrolysis is decreased that the other pesticide existed. It is possible that the otherpesticide or metabolic product quenched the photolysis of triazophos and its half-lifewas increase. It can provide some referential basis for research hydrolysis andphotolysis of triazophos.