Synthesis Of Modified Tertiary Amine Resin And Its Adsorption For Micro Pollutants In Water

With the increasing pollutants in raw water,adsorption resin has received extensive attention due to its feasible manipulation,good adsorption selectivity,high mechanical strength,considerable stability and easy regeneration.Therefore,the development in the field of water treatment is focused on adsorption resin with low cost,high efficiency,environmental friendliness and wide applicability.In this thesis,the tertiary amine resin（TAR）who was prepared by suspension polymerization was modified with HCl to obtain the tertiary amine hydrochloride resin（TAHR）,with iodomethane to obtain the quaternary ammonium iodide resin（QAIR）,with benzyl chloride to obtain the quaternary ammonium chloride resin（QACR）,and with hydrogen peroxide to obtain the tertiary amine oxide resin（TAOR）.Then,the quaternary ammonium acetate resin（QAAR）was derived from the reaction of the QAIR and CH₃COOH.Their physicochemical structures were characterized by analytical methods of FTIR,SEM,and nitrogen adsorption and desorption（BET）.And their thermal stability were tested by thermogravimetry（TG）.Their adsorption properties for micro pollutants（halogen ions,oxoanions and dyes）in water were investigated by adsorption experiments,in which various factors such as initial concentration of solution,adsorbent dose,contact time,pH value,ionic strength and coexisting ions on the adsorption property were investigated.Their adsorption kinetics,thermodynamics and equilibrium isotherms,as well as their reusability and regeneration performance,were also studied.Finally,the effects of coupling process between disinfection and adsorption were evaluated.The theoretical maximum adsorption capacities of the halogen ion Br^-and its oxoanion BrO₃^-are 2.06 mmol/g and 1.85 mmol/g for TAHR,1.76 mmol/g and1.69 mmol/g for QAIR,2.32 mmol/g and 2.03 mmol/g for QAAR,2.30 mmol/g and 2.23 mmol/g for QACR,respectively,while that for TAR is negligible.It is clear that the modification on the matrix resin TAR greatly enhance the adsorption effect on Br^-and BrO₃^-.In the binary mixed system of Br^-and BrO₃^-,four modified resins all exhibit better selectivity for Br^-than BrO₃^-.By comparison,TAHR,QAIR,QAAR and QACR are found to have better adsorption capacity than that of most commercial resins,which shows they are the interesting potential candidates in the removal of micro pollution from water because of their impressive adsorption performances.The process coupling test shows that the residual concentration of Br^-and BrO₃^-in the effluent that treated by the coupling process of adsorption following O₃disinfection is 31.0%and 34.5%lower than that of O₃disinfection following adsorption,respectively.Obviously,the coupling process of adsorption following O₃disinfection is more favorable to the deep removal of Br^-and BrO₃^-in practical engineering application.The theoretical maximum adsorption capacity of TAHR for the NO₃^-,a common inorganic oxoanion in water,was much higher than that of its matrix resin TAR,2.94 mmol/g and 1.26 mmol/g,respectively;Still,it was better than some commercial resins such as D301 at 2.66 mmol/g and IRA-67 at 2.58 mmol/g.The theoretical maximum adsorption capacity of TAOR for the Congo Red（CR）,an organic oxoanion was also higher than that of its matrix resin TAR,101.96 mg/g and 86.25 mg/g,respectively.It shows that the modification on the matrix resin TAR is also beneficial for the removal of other inorganic or organic oxoanions。pH has a large effect on the adsorption of Br^-,BrO₃^-,NO₃^-and CR because it is the impact on the protonation degree of resin donor atoms.The results show that the adsorption of Br^-,BrO₃^-,NO₃^-and CR by these modified resins is unimolecular layer adsorption thanks to their isothermal adsorption data fitting the Langmuir model（R~2>0.99）.The adsorption kinetics of these modified resins can be described by the pseudo second order kinetics（R~2>0.99）that shows their adsorption rate are controlled by chemical adsorption related to transfer and share electron.The mechanism study has demonstrated that,for these modified resins,ion exchange force plays an important role in their adsorption of Br^-,BrO₃^-,NO₃^-and CR,while electrostatic interaction force is the secondary adsorption mode.Compared with matrix resin TAR,in this paper,several kinds of modified resin in adsorption to remove the water pollutant has the outstanding performance,show that the synthesis of new adsorption material is expected to be applied to remove the micro pollutants in the water,to provide new material for water treatment,adsorption/disinfection coupling process optimization of the experimental results in engineering applications can improve the efficiency of water treatment.