Study On The Inhibition Effect Of Sulur Based Compound Inhibitor On AOX Formation In Pulp Bleaching Process

AOX can be greatly reduced by ECF bleaching,but it is difficult to be degraded and has bioaccumulation.It is necessary to study further the reduction technology of AOX.In this paper,the method of sulfur-amine compound inhibitor is used to research the reduction effect of the AOX generation.This paper selected the(NH4)2S2O3 as the research object by comparing the inhibitory effect of(NH4)2S2O3,H3N03S and H4N2O2S on AOX generation during pulp bleaching.The unbleached bagasse kraft pulp as raw material,on the basis of single factor analysis,study the effects of adding(NH4)2S2O3 time,adding dosage,reaction temperature,pH and reaction time on the change of AOX reduction.The appropriate reaction conditions to achieve a balance of reduced AOX content,higher brightness and higher viscosity were as follows:available chlorine dosage was 1.6%,pH value was 4,reaction temperature was 70?,(NH4)2S2O3 adding time was in the bleaching reaction 10min,adding dosage was 0.20%.AOX content of D0 bleaching effluent is 33.55 mg/L,compared with the without(NH4)2S2O3 bleaching wastewater,the AOX content was reduced by 21.99%.Meanwhile,the bleached pulp brightness reached 79.95%ISO and the viscosity was 1002.27 mL/g.The detection and analysis of Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy(ATR-FTIR),Scanning Electron Microscope and Energy Dispersive Spectrometer(SEM-EDS)for D0 bleached pulp on whether adding ammonium thiosulfate,found that the phenolic lignin and guaiacyl lignin are reduced by adding(NH4)2S2O3 in the bleached pulp,but the-C=O structure of lignin can be persisted.More lignin was exposed on the surface of the fiber,which was helpful for the subsequent bleaching.Detected of bleaching wastewater by UV spectrometer and GC-MS.It was found that the chlorobenzenes and chlorophenols were significantly reduced in the bleaching wastewater,with adding(NH4)2S2O3.The kinetics of the reaction between(NH4)2S2O3 and AOX simulant(2,4,6-trichlorophenol)was studied under simulated bleaching conditions.The reaction products were detected by GC-MS,and speculated the reaction pathway between(NH4)2S2O3 and 2,4,6-trichlorophenol.The kinetic data were collected by UV spectrophotometer,deduced the two order rate equation for the reaction of(NH4)2S2O3 with 2,4,6-trichlorophenol as-d[(NH4)2S2O3]/dt=k'[2,4,6-TCP][(NH4)2S2O3]where k' refers to observed second-order rate constants.This could provide theoretical reference for the research of AOX reduction technology.