Preparation,Characterization And Application Of Rapid Separation Porous Adsorption Materials

Water pollution problems have posed a serious threat to the health of human and other living organisms due to the increasing global contamination of various water resources by organic micropollutants and heavy metal ions.It has been a challenging problem to remove those organic micropollutants,despite of various attempts.Therefore,an adsorbent material with cost-effective,rapid adsorption,strong adsorption capacity,high selectivity,high cycle stability and high reusability has been developed,that has a high application value.In this paper,the?-cyclodextrin modified adsorbents and polyethyleneimine modified adsorbents were prepared,as well as the adsorption towards organics and heavy metal ions was studied.The main research contents are as follows:?1?A series of?-cyclodextrin porous adsorbent materials were prepared by reaction through?-cyclodextrin and different crosslinkers.The?-cyclodextrin porous adsorbent was characterized by FT-IR,NMR,XRD,BET,and SEM.The adsorption properties of?-cyclodextrin porous adsorbent were further studied by static adsorption,rapid adsorption,regeneration performance and selectivity experiments.The results show that the rigidity of the cross-linking agent has a great influence on the adsorption performance of the material.Among them,the?-cyclodextrin porous adsorbent?BP-CDP?with high rigidity biphenyldibenzyl chloride as the cross-linking agent has excellent adsorption performance.88%of bisphenol A?BPA?can be removed in 1 minute for BP-CDP,and its maximum adsorption capacity(q_max,e)is139 mg/g.The adsorption process is fitted well with the pseudo-second-order kinetics and the Langmuir isothermal adsorption model,suggesting that the adsorption process of BPA by BP-CDP is a chemical adsorption of monolayer.In addition,the adsorption ability of BP-CDP was kept nearly unchanged after five filtration regeneration cycles,which shows that it has the regeneration and reuse properties.?2?A series of PEI-based porous adsorbent materials?TPEIs?were prepared by reaction through polyethyleneimine?PEI?and cyanuric chloride.The TPEIs were characterized by the methods of FT-IR,NMR,BET,and SEM.The adsorption properties of TPEIs on organic compounds were studied by static adsorption,rapid adsorption and regeneration performance.The results show that the adsorption capacity of TPEIs adsorbents has been effected by different nitrogen to chlorine ratio,its properties order is TPEI?6:1?>TPEI?4:1?>TPEI?2:1?>AC.The adsorption rate of terephthalic acid?TA?for TPEI?6:1?is as high as 98%within 10 seconds,which is three times higher than that of activated carbon,and its saturation capacity is 965mg/g.The adsorption kinetics and adsorption isotherm model further proves that the adsorption of TA by TPEI?6:1?according with pseudo-secondary kinetics and Langmuir isotherm model,indicating that the adsorption process of TA by TPEI?6:1?is single-layer chemical adsorption.TPEI?6:1?still has good adsorption capacity after5 times adsorption/desorption experiments.In addition,TPEI?6:1?has good adsorption properties for organic micro-pollutants such as diphenyl phthalate and4-aminotoluene-3-sulfonic acid.Finally,the adsorption performance of TPEI?6:1?on phthalocyanine blue and lisol red dye wastewater was studied.The results show that the material has excellent adsorption and regeneration ability for dyes.?3?The adsorption properties of polyethyleneimine porous adsorbents on noble metal ion Au³⁺were studied.The optimal conditions for adsorption experiments were determined by exploring the effects of pH,temperature and the initial concentration on the adsorption process of Au³⁺.The adsorption properties of polyethyleneimine porous adsorbents on Au³⁺were studied by static adsorption,rapid adsorption and regeneration performance.The results show that TPEI?6:1?has good adsorption capacity for Au³⁺at 25°C and pH at7,and 95.6%of Au³⁺can be removed in 10seconds.The saturated adsorption capacity is 5386.5 mg/g,and the equilibrium adsorption rate is 97%.The adsorption kinetics and adsorption isotherm model further prove that the adsorption of Au³⁺by TPEI?6:1?fitting with pseudo-secondary kinetics and Langmuir isotherm model,indicating that the adsorption process of Au³⁺by TPEI?6:1?is single-layer chemical adsorption.After 5 times adsorption/desorption regeneration experiments,TPEI?6:1?still has excellent adsorption capacity.Finally,the adsorption mechanism of TPEI?6:1?on gold ion adsorption was investigated by SEM,XPS and FT-IR.The characterization results show that the adsorption process of TPEI?6:1?on Au³⁺is mainly coordination and ion exchange.The amino group is reduced to Au⁺and Au by an in-situ reduction reaction,and the elution of the thiourea does not change the group of the material structure,and multiple cycles of regeneration can be performed.