Research On Treatment Of High Concentration Phenolic Resin Wastewater By Concentrated Sulfuric Acid Oxidation Method

As an important industrial phenolic resin raw material is widely used in the national economic field,while at the same time,it will produce a large amount of industrial wastewater during the the synthesizing process of phenol-formaldehyde resin.The typical characteristics of the wastewater are complicated compositions,toxicity,high organic concentration,environmental pollution and harmful to human health.The phenolic resin wastewater which belongs to refractory organic wastewater mainly contains part of free phenol,formaldehyde and other organic compounds.The range of phenols is 16-440 g/L,the range of formaldehyde is 20?60 g/L,and the COD concentration can be up to hundreds of thousands.Phenol is a kind of highly toxic chemicals,the low concentration of phenol can make the cell degeneration,and high concentration can make the protein coagulation,which can go through the skin mucous membrane,respiratory and digestive tract into the body.Low concentration can lead to accumulative toxicity,high concentration can lead to acute poisoning and death.Formaldehyde is the main material of the aldehyde pollutants and its characteristic is acute poisoning.It can strongly stimulate eyes,respiratory and skin.In phenolic resin wastewater,it also contains a large number of small molecule phenolic resin,phenolic resin polymers,methanol and other substances besides high concentration of phenols,aldehydes.The phenolic resin wastewater comes from an enterprise of Shandong province.COD concentration of the wastewater is 172500 mg/L,the concentrations of free phenol free formaldehyde respectively in the wastewater are 16500 mg/L and 2300 mg/L,and pH is 8.93.Because of the high concentration of formaldehyde,phenol,the wastewater has strong toxicity and inhibition for microbes,so the wastewater can not be directly treated by biochemical method.Hence pretreatment is necessary through a series of physical and chemical treatment.As for this topic,we mainly treated the high concentration phenolic resin wastewater by chemical oxidation process.By using concentrated sulfuric acid(W(H2S04)=98%))as oxidizer,because of the pH of the wastewater is 8.93,some of the concentrated sulfuric acid used as neutralizer.Then the residual concentrated sulfuric acid was used as oxidizer.The innovation of this method is that we use the concentrated sulfuric acid was as 'solvent',the wastewater as 'solute',In the process of distillation,we make the concentrated sulfuric acid and the wastewater mixed according to a certain proportion to distill,100:5,100:10,100,15,100:20,100:25,and then recover the water.Four distillation units are necessary for this topic:1?heating jacket ? distilling flask? condenser tube? nozzle ?receiving bottle;2?heating jacket ? distilling flask ?tee joint ? two condenser tubes(the above and the right side)?the right condenser tube connects to the nozzle ? receiving bottle;3?heating jacket ? distilling flask ? condenser tube ? nozzle? receiving bottle ? vacuum pump;4?heating jacket? distilling flask ?tee joint? two condenser tubes(the above and the right side)?the right condenser tube connects to the nozzle ?receiving bottle ? vacuum pump.The results showed that the optional operation method is concentrated sulfuric acid and the wastewater are mixed in 100:5,then the effluent is treated by the CaCO3,the NO.2 distillation unit's treatment effect is the best and removal rate is the highest.The final COD concentration of the wastewater was 1098.32 mg/L,with the removal rate of 99.36%;the concentration of free phenol was 470,40 mg/L,with the removal rate of 97.15%,the concentration of free formaldehyde was 0 mg/L,with the removal rate of 100%.Through the above analysis,treatment of high concentration phenolic resin wastewater by concentrated sulfric acid oxidation method has remarkable effect.