| Phenol hydrogen peroxide hydroxylation method is an important method for industrial production of catechol and hydroquinone,but this treatment of phenol hydroxylation products has the problem of high energy consumption and the problem of high harm,high toxicity and difficult treatment of phenol-containing wastewater generated during the treatment process.Liquid membrane technology is the coupling of extraction and backextraction,with low energy consumption,high selectivity and low investment cost.Hollow fiber renewal liquid membrane technology(HFRLM)not only inherits the advantages of liquid film technology,but also solves the problem of liquid film instability,and has great application potential in enrichment concentration and wastewater treatment.In this paper,HFRLM was used to treat phenol hydroxylated products and phenol-containing wastewater with low energy consumption,and in order to achieve high selectivity of HFRLM for phenol hydroxylation products and efficient enrichment treatment of low-concentration phenol-containing wastewater,experimental research on the extraction process and HFRLM process was carried out,the extraction agent was selected as the liquid film phase,and the treatment effect and operating conditions of HFRLM were investigated.This paper studied the extraction equilibrium experiment,the TOP/kerosene extraction system was used as the extraction system,the effects of feed liquid pH,extractant concentration,and oil water ratio on extraction efficiency were studied.The results showed that acidic feed solution is beneficial for the extraction of phenol and dihydroxybenzene(catechol and hydroquinone),and alkali solution can be used as a stripping phase for the regeneration of extractant.The partition coefficients of phenol and dihydroxybenzene were increased with the increase of extractant concentration.With the study of the complexation mechanism,it is concluded that TOP formed a 1: 1 complex with phenol,while TOP and catechol formed1: 1 and 1: 2 complexes,and TOP formed a 1: 2 complex with hydroquinone.Phenol solution and three phenol mixed solutions(phenol,catechol,and hydroquinone)were used to simulate phenolic wastewater and phenol hydroxylation reaction mixture,respectively.HFRLM experiments were from self-made hollow fiber membrane contactors and used TOP/kerosene as the liquid membrane phase.The effects of various factors such as initial concentration and pH of feed solution,and pH of stripping phase on the treatment efficiency of HFRLM were investigated.The results show that HFRLM technology has a good removal and enrichment effect on phenol wastewater.For a 1 g/L phenol solution,the concentration after treatment reaches 0.483 ppm,which meets the emission standard.And the recovery rate of phenol reached 93.8%,that means HFRLM had a good effect in the treatment and recovery of phenol-containing wastewater..After 89 hours of long-time treatment,the enrichment factor of phenolic reaches 69.3 times,which indicates that HFRLM technology has a high stability.When the feed pH is 5 and the stripping phase pH is 14,HFRLM also has efficient enrichment of three phenol mixed solutions over 24 hours.HFRLM enables low-energy treatment of phenol hydroxylated products. |
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