Research On The The Treatment Of Waste Cutting Fluid By The Combined Process Of Persulfate And Fenton

Cutting fluid is a more widely used lubricant in the machining industry?The cutting fluid will deteriorate and fail in use,resulting in a large amount of cutting wastewater.Untreated cutting wastewater can cause serious damage to human and environment,and its mineral oil and nitrosamines have carcinogenic physiological toxicity.Cutting wastewater has the characteristics of high COD,high chromaticity and poor biodegradability.Its additives such as antirust agents and surfactants have strong stability for cutting wastewater.It is difficult to remove effectively under conventional conditions.We have advanced and matured technology in practical engineering.In order to further optimize the process flow,we try to use the advanced oxidation technology of persultate and Fenton to study the treatment of the waste cutting fluid in this paper.Taking waste cutting fluid for research objects,firstly we study the optimum reaction conditions and treatment effect on the demulsification of waste cutting fluid by acidation-coagulation method,then we take a treatment using the method of zero-valent iron activation and thermal activation,finally,we use two stage Fenton oxidation process to treat the subsequent waste cutting fluid.In the experimental stage of demulsification of waste cutting fluid in acidation-coagulation,the results show that the reaction temperature has a great influence on the demulsification of acid analysis.The acid analysis with heat destroy the stable structure of the waste cutting fluid and destabilize the oil droplets,and then the oil and water separation was realized by coagulation.The optimum treatment conditions were as follow:when the concentration of concentrated sulfuric acid was20ml/L and the reaction temperature was 70°C,the removal rate of COD in the wastewater was 41.07%in the stage of acid analysis.When the concentration of the amount of PAC added was 10g/L,and pH was 6.1,COD was reduced from initial96400mg/L to 36000mg/L,and the removal rate of COD reached 62.65%finally.In the experimental stage of waste cutting fluid in persulfate oxidation,the results show that both zero-valent iron activation and heat activation can promote persulfate to produce sulfate radical which is more oxidizing.But the method of heat activation is better than zero-valent iron activation.The influence of the three factors on the treatment of zero-valent iron activation system was as follow:ZVI dosage>Na₂S₂O₈dosage>pH?The optimum treatment conditions were as follow:the dosage of Na₂S₂O₈was 24g/L,the dosage of ZVI was 3g/L,the reaction time was 6h,and pH4.5 and the removal rate of COD reached 47.11%finally.The influence of the three factors on the treatment of heat activation system was as follow:reaction temperature>reaction time>Na₂S₂O₈ dosage.The optimum treatment conditions were as follow:the dosage of Na₂S₂O₈ was 36g/L,the reaction temperature was 80°C,the reaction time was 4h,the pH was neutral,and the removal rate of COD reached 56%.In the experimental stage of depth treatment of waste cutting fluid in two stage Fenton.the results show that the best reaction conditions for the treatment of wastewater by the first level Fenton method was as follows:the dosage of H₂O₂ was60ml/L,the dosage of FeSO₄.7H₂O was 20g/L,the reaction time was 100min,and pH 2,the removal rate of COD reached 71%;the second level Fenton method was as follows:the dosage of H₂O₂ was 70ml/L,the dosage of FeSO₄.7H₂O was 30g/L,the reaction time was 60min,and pH 2,the removal rate of COD reached 65.52%,the value of the effluent COD was 400mg/L.After treatment,the value of COD reach the emission requirements of the municipal pipe network?500mg/L?and achieves the purpose of the experiment.