Adsorption Of Typical Organic Pollutants From Water By ZIFs Modified Porous Carbon

Porous carbon is one of the most commonly used adsorbent materials.However,for the removal of organic matter in water,there are shortcomings of poor adsorption selectivity and low adsorption capacity.Zeolitic imidazolate frameworks(ZIFs)was loaded on the porous carbon surface by different methods.In this paper,the obtained materials were characterized by X-ray diffraction(XRD),Scanning electron microscopy(SEM),Fourier transform infrared spectrometer(FT-IR),Raman spectrometer(Raman),X-ray photoelectron spectroscopy analyzer(XPS),physical adsorption instrument(BET)and thermogravimetric analyzer(TG).Its aim is to analyze the properties of chemical composition information,structure,morphology and thermal stability of the materials.The adsorption property of the material to remove organic pollutants from water was also studied.The specific research contents are as follows:A trace amount of ZIF-67 was loaded onto activated carbon(AC)particles by impregnation method and subsequently calcined at 800°C for 6 h.The obtained material(cal-ZIF-67/AC)showed highly dispersed Co and N on its surface and its specific surface area was 833 m~2/g,equivalent to the original activated carbon.Besides,it also exhibited weak magnetic property.The cal-ZIF-67/AC was further used as adsorbent for Rhodamine B(RhB)removal.It was found that cal-ZIF-67/AC exhibited good adsorption performances for RhB.When the adsorption temperature was 30 ~oC and the concentration of RhB was 150 mg/L,the maximum adsorption capacity was46.2 mg/g,more than twice that of AC.Besides,it showed good recycling performance.Activated carbon particles(AC)supported by ZIF-8 were synthesized by impregnation technique,and modified activated carbon(ZIF8/AC)was obtained after calcining.The material has a large surface area and pore volume,with trace of Zn and N evenly distributing on the surface.Subsequently,the adsorption properties of the ZIF8/AC samples to adsorb and remove phenol from aqueous media was evaluated.In addition,adsorption kinetics results were examined by pseudo-first and pseudo-second order models,and adsorption isotherms data were fitted into Langmuir and Freundlich equations.The experimental results showed that the adsorption capacity of phenol on ZIF8/AC reached 155.24 mg/g,which was 2.3 times greater than that of the pure AC.The results showed that the adsorption of phenol on ZIF8/AC was in accordance with the pseudo-second-order kinetic model and Freundlich isotherm model.In addition,ZIF8/AC can be easily separated from the solution and has good cyclic adsorption performance.Here,well-dispersed ZIF-8 is successfully grown onto porous carbons by an in-situ growth method,with a surface area up to 136.5 m~2/g.The resultant ZIF8/Carbon shows excellent adsorption removal efficiency for malachite green(MG)with a maximum adsorption capacity of 3056 mg/g at 30°C.The adsorption kinetics and isotherm data fit well with the pseudo-second-order kinetic model and Langmuir isotherm model,respectively.Furthermore,the influences of temperature,solution pH and inorganic salt concentration are also investigated.The adsorbent has a large particle size and is easy to be separated.Moreover,regeneration experiments reveal that the adsorption capacity still exhibits excellent after at least four recycling runs.