Preparation And Adsorption Mechanism Of High Performance Carbon-based Adsorbents

In recent decades,the development of industrial and fertilizer manufacturing industry has brought people convenience,but also brought a series of environmental problems,water and soil heavy metal and inorganic salt pollution is particularly severe.There is an urgent need to address the problem of pollution while avoiding new pollution.This study used glucose as the main raw material to prepare hollow carbon spheres(HCSs)and nitrogen-doped carbon spheres(CSs-N)using glucose and urea.Using HCSs and CSs-N as precursors,a series of high-performance porous carbon materials were prepared for adsorption of Cr(Ⅵ)and phosphorus in water,and their structural characterization and adsorption properties were tested.The whole preparation process is non-toxic and non-residual,and the porous carbon materials have excellent performance in adsorbing pollutants,which provides a green and efficient for the field of water and soil environmental pollution prevention and control.In this study,using glucose as raw material and sodium dodecyl sulfate(SDS)assurfactant,was prepared under 180℃hydrothermal conditions HCSs,followed by activation of HCSs using potassium hydroxide to produce a honeycomb-like carbon material(HCM).HCSs and HCM were characterized by SEM,TEM,BET specific surface area,Raman spectroscopy,XRD,XPS and elemental analysis.The adsorption performance of HCM to Cr(Ⅵ)was tested by batch adsorption experiment.SEM and TEM images show that the pore structure of HCM is well developed.TEM images show that the carbon sphere is hollow.The specific surface area of HCM measured by BET is 1436.21 m~2/g,which is about 140 times larger than that of HCSs.The results of batch adsorption experiments showed that the best adsorption p H point of Cr(Ⅵ)on the HCM was around 2,and the maximum adsorption capacity of HCM for Cr(Ⅵ)is 332.53 mg/g at p H 2 and temperature 25℃.The adsorption process accords with the pseudo-second-order kinetic model and the Langmuir model.The experimental results of regeneration adsorption show that HCM has good reusability for Cr(Ⅵ)adsorption.nitrogen-doped carbon spheres were prepared by 185℃hydrothermal reaction using glucose and urea as raw materials and SDS as surfactants.nitrogen-doped porous carbon materials(PCM-N)were prepared by activation at 800℃using potassium hydroxide as activator.CSs-N and PCM-N were characterized by SEM,SEM,TEM,BET specific surface area,Raman spectrum,XRD,XPS and elemental analysis.The adsorption property of the material was tested by the intermittent adsorption method.SEM and TEM images show that the surface of PCM-N is well developed and the TEM shows that CSs-N is solid and is no longer a hollow structure.The BET surface area of PCM-N was 1600.67 m~2/g,much higher than CSs-N.Batch adsorption experiments showed that the optimum adsorption p H of PCM-N for Cr(Ⅵ)was 2.The maximum adsorption capacity of PCM-N to Cr(Ⅵ)reached 402.9 mg/g at p H 2 and temperature 25℃,far exceeding that of similar materials at home and abroad.PCM-N adsorption process for Cr(Ⅵ)was in accordance with the pseudo-second-order kinetic and Freundlich models.The regeneration adsorption experiments showed that PCM-N had high reusability for Cr(Ⅵ)adsorption.Due to PCM-N excellent properties and high heavy metal removal performance,we further use PCM-N for phosphorus removal in water.PCM-N adsorption properties of phosphorus in water were tested by batch adsorption experiments.The results show that PCM-N has excellent adsorption performance for phosphorus,and batch adsorption experiments show that the best adsorption p H value is 2.the maximum adsorption capacity of PCM-N for phosphorus was 62.11 mg/g under 25℃conditions,and the adsorption capacity would be further increased with increasing temperature.Adsorption process was in accordance with pseudo-second-order kinetic model and Langmuir model.Thermodynamic calculations show that the adsorption process is a spontaneous endothermic reaction.The regeneration experiments show that PCM-N has high regeneration adsorption performance for P.In this study,a series of high-performance adsorbent were prepared by hydrothermal activation method with glucose.The results show that the materials had high adsorption capacity and good regeneration adsorption performance for Cr(Ⅵ)and P in water.This study provides a new ideas and methods for the preparation of carbon materials with high adsorption capacity and high reusability,and provides new theoretical and technical support for the prevention and control of soil and water pollution.