Preparation Of Polycyclic Polymer And Study On The Adsorption Efficiency Of Brominated Flame Retardant From Water

The use of flame retardants facilitates human production and life,but also produces a new type of persistent organic pollutants--Brominated Flame Retardants?BFRs?that threaten human survival and development..BFRs can not be effectively removed in the wastewater treatment process of sewage plants,and the unpurified BFRs will enter the natural water body after the treatment,which will threaten the natural environment and human health.The easy-to-use and non-secondary pollution treatment process is the trend of the public choice,and the adsorption method stands out from this.Meantime,polymer adsorbents are also emerging with their advantages of stable properties and targeted properties.In this paper,according to the structural characteristics of additive BFRs and reactive BFRs,a kind of polycyclic polymer adsorption material with a large adsorption capacity was designed and synthesized,and the adsorption and regeneration experiments were carried out,which provided new material support for the deep purification of BFRs polluted wastewater.The Azo polycyclic polymer?AzO-POP?synthesized by electrophilic substitution and repolymerization had a specific surface area of up to 1478 m²·g^-1.,When it adsorbed BFRs-pentabromotoluene(PBT,1 mg·L^-1),the adsorption equilibrium time was 10 min,and the saturated adsorption amount can reach 10.71 mg·mg^-1,and the adsorption process conformed to quasi-second-order kinetics.The main reason for the large adsorption capacity is the?-?bond interaction,hydrophobic interaction and pore filling effect between the functional framework of the material and PBT.The fitting results of the intra-particle diffusion model showed that external diffusion and internal diffusion jointly control the adsorption process.It can be seen from the thermodynamic results that the adsorption process was based on multi-layer adsorption and was accompanied by a non-uniform adsorption process of monolayer adsorption,which is a self-releasing thermal reaction.The change of inorganic cation strength had a relatively significant effect on the adsorption,and the coexistence of pentabromodiphenyl ether?BDE-99?in water had a competitive adsorption on PBT.The dynamic adsorption shows that the adsorption process is more in line with Thomas'classical model,indicating that in the dynamic adsorption process,both internal and external diffusion are non-rate-limiting steps..The best regenerant of AzO-POP solvent regeneration method is n-hexane.The raw material cost per ton of water for AzO-POP treatment of added BFRs is about 0.43 yuan.In order to reduce the cost of water treatment and efficiently remove reactive flame retardants with active reactive groups,in this study,a natural material-?-cyclodextrin with a large number of hydroxyl groups was selected as the raw material,and prepared a cyclodextrin polycyclic polymer adsorption material??-CD-POP?with a raw material cost of 0.028 yuan per ton of water treatment.The adsorption performance of?-CD-POP on reactive flame retardant-tribromophenol?TBP?showed that the adsorption process of TBP on?-CD-POP is dominated by quasi-second-order kinetic model and Langmuir model.which belongs to spontaneous chemical adsorption process.The adsorption equilibrium time was 30 min and the maximum adsorption capacity was 215.51mg·g^-1The adsorption process is controlled by external diffusion and internal diffusion and the adsorption of TBP by?-CD-POP was driven by?-?interaction,hydrogen bond and physical pore filling.The saturation adsorption capacity was affected by the concentration of inorganic metal ions such as Na⁺,Ca²⁺,Mg²⁺due to the complexation of TBP and inorganic metal ions,and there was competitive adsorption due to the coexistence of BDE-99.Thomas and Yoon Nelson model are more suitable for the dynamic adsorption process than Yan model.The regenerant of?-CD-POP is ethanol.