Designation Of Three-dimensionally Ordered Macroporous Adsorbents For Removal Heavy Metal Ions And Its Application

Nowadays, heavy metal pollution has become one of the major problems of environmental pollution, which can bring great harm to human, such as kidney and liver diseases, respiratory diseases and skin cancer. Therefore, the adsorbents for removal heavy metals haave arosed in the research area. In conclusion, 3-D ordered macroporous（3DOM） adsorbent will possesss outstanding prospect.1. A novel 3-D ordered macroporous（3DOM） adsorbent with a cationic polymer chain（poly（N,N-dimethylaminoethyl methacrylate）, PDMAEMA）) tethered on the pore wall was prepared by surface-initiated atom transfer radical polymerization（SI-ATRP） for the removal of Cr（VI） ions from aqueous solution. In comparison with recently reported adsorbents, the adsorbent remarkably stands out owing to large adsorption capacity, relatively fast kinetics, and high stability in the regeneration process. The effects of p H and additional iron strength as well as adsorbent dose on the adsorption performance were examined. The adsorption capacity significantly depended on the solution pH and there was a wide working pH range. Kinetics of Cr（VI） adsorption by the 3DOM adsorbent were studied in batch static experiments, in the temperature range 298-318 K. The equilibriums were arrived within 120-130 min and a pseudo-second order model can be described well. In the adsorption isotherm study, experimental data followed the Langmuir adsorption model. The maximum adsorption capacity increased with the increase of temperature, and reached the high value of 431.0 mg/g at 308 K. Thermodynamic parameters revealed spontaneous and endothermic adsorption processes. Furthermore, sodium hydroxide solution as the desorption liquid,the 3DOM adsorbent remained high adsorption capacity（above 90% of the original Cr（VI） loading capacity） after 15 adsorption-desorption cycles and retained the 3-D ordered macroporous structure showed by SEM, which ensured the reusability of 3DOM CLPS-g-PDMAEMA.2. The three-dimensionally ordered macroporous（3DOM） silica was made by colloidal crystal template method. Then, the polymer chains of PtBA controllable introduced onto the pore wall of 3DOM SiO₂. After hydrolysis of 3DOM SiO₂-g-PtBA, 3DOM SiO₂-g-PtBA reacted with diethylenetriamine（DETA）. The adsorption capacity of 3DOM SiO₂-g-PtBA-DETA significantly depended on the solution pH and showed the biggest adsorption capacity of 90mg/g at pH=5. Kinetics of Cr（VI） adsorption by the 3DOM adsorbent were studied in batch static experiments, in the temperature range of 298-318 K. The equilibriums were arrived within 60 min and a pseudo-first order model can be described well. In the adsorption isotherm study, experimental data followed the Freundlich model. Thermodynamic parameters revealed spontaneous and endothermic adsorption processes. Furthermore, the 3DOM adsorbent remained high adsorption capacity（above 80% of the original Cr（VI） loading capacity） after 6 adsorption-desorption cycles and retained the 3-D ordered macroporous structure showed by SEM, which ensured the reusability of 3DOM SiO₂-g-PtBA-DETA.