Reactive Extraction Of O-toluidine Wastewater

Toluidine is a widely used chemical intermediates,also a toxic polar organics.Because of complex composition,the industrial waste water of toluidine has high COD,when direct emissions will cause serious environmental pollution,harm to human and ecological environment.Therefore,recycling the industrial wastewater of o-toluidine is meaningful on ecological environment protection and industrial waste resource.Firstly,the experiment explores the different extraction balance of reactive extraction of o-toluidine solution,find that the selection of di(2-ethylhexyl)phosphoric acid(D2EHPA),naphthenic acid,tributyl phosphate(TBP)as extracting agent,n-octanol,butyl acetate,kerosene as polar diluent,established nine different extraction systems.The extractant type and concentration,diluent species,extraction equilibrium pH(pHeq),the concentration of o-toluidine effect extraction of o-toluidine.The results showed:effect of three extracting agent D2EHPA>TBP>naphthenic acid;its extraction distribution ratio D is increased with concentration of the extraction agent.For D2EHPA and naphthenic acid system,n-octanol better than butyl acetate,butyl acetate better than kerosene,the distribution ratio increases with pHeq.For TBP system,kerosene better than butyl acetate,butyl acetate better than n-octanol,the distribution ratio appears peak at extraction equilibrium at 7.5,9,andll.For the nine kinds of extraction system,the distribution ratio increased with o-toluidine concentration;the 1.470mol/L D2EHPA-optimum is the best extraction system.At the same time the its coexisting components effect results of extraction:under basic conditions at room temperature,use 1.470mol/L D2EHPA-octanol extracting toluidine wastewater,the aniline and sodium(salt)o-toluidine harm to the results of extraction,phenol and nitrobenzene concentration due to its much smaller than the o-toluidine,does not have a significant effect on the extraction of o-toluidine.Secondly,according to the experimental results,di(2-ethylhexyl)phosphoric acid-octanol extraction system in the o-toluidine for synthesis salt ion association,and the establishment of its extraction model,calculate the apparent equilibrium constant.Thirdly,use acidic substances as stripping agent,achieved good extraction solvent regeneration,waste water can be recovered in a useful resource;to the above studies as a basis for o-toluidine industrial wastewater treatment,under alkaline room temperature,di(2-ethylhexyl)phosphoric acid-octanol as extracting agent,acidic solution(sulfuric acid,HCl)as a stripping agent,o-toluidine industrial wastewater three cross-flow extraction process-under the conditions of use of di(2-ethylhexyl)phosphoric acid wastewater discharge standards.