Studies On The Electrochemical And Flocculational Performances Of Polycationic PDMDAAC And Its Applications

PDMDAAC?poly dimethyl diallyl ammonium chloride?is a kind of water-soluble cationic polymer which has good electric conductivity due to its strong electric neutralization capacity and excellent adsorption bridging capacity.It has been widely applied as electrochemical sensors in analytic chemistry or as flocculants in water treatment.The monomer DMDAAC was synthesized via a two-step alternate-dropping method.Then,PDMDAAC was synthesized via a three-stage-heating method,with ammonium persulfate?APS?as initiator and isodium edetate?Na₂EDTA?as complexing reagent.IR and¹H NMR were used to characterize the structure of the monomer or polymer.In this paper,firstly,influence factors including the intrinsic viscosity of polymer and the conversion rate of monomer were studied,such as concentration of monomer,amount of initiator and complexing reagent,and the reaction time.The optimum conditions were as follows:the concentration of monomer was 65%,and the amount of APS or Na₂EDTA was0.35%or 0.0035%,respectively,and the reaction time and temperature of the three stage was2 h at 45?,3 h at 55.5?,3 h at 67?,respectively.Secondly,this paper focused on the electrochemical properties and applications of PDMDAAC.A novel poly-dimethyl-diallyl-ammonium chloride/cellulose sodium sulfate modified glassy carbon electrode?NaCS/PDMDAAC/GCE?was prepared by coating method.The morphology of modified electrode was characterized via scanning electron microscopy?SEM?.The surfacial electron transporting capacity of different modified electrodes and their electrochemical properties were characterized by cyclic voltammetry.The oxidation behavior of nitrite on the electrode was investigated by cyclic voltammetry?CV?and differential pulse voltammetry?DPV?.Results showed that the oxidation peak current was linearly related to the nitrite concentration in the range of 4.0×10^-81.5×10^-4 mol?L^-1?r=0.9948?and the detection1imit was 5.2 nmol?L^-1.In addition,the modified electrode exhibited good selectivity,reproducibility and stability.Then,this novel NaCS/PDMDAAC/GCE electrode was applied to the determination of nitrite levels in ham sausages.Thirdly,the flocculational performances of PDMDAAC were studied by UV-vis.Results showed that when the dosage was 2 mg/L,pH was 7,and the temperature was 50?,standed for 10 min,PDMDAAC exhibited a good flocculational performance with the best permeability rate,and the ratio of the permeability rate in the presence/absence of PDMDAAC was 9.5:1.