We investigated the adsorption performance of five Fe-based MOFs(Fe-BTC,MIL-100(Fe),MIL-101(Fe),MIL-53(Fe)and MIL-88 C(Fe))for removal of antimonite(Sb(Ⅲ))and antimonate(Sb(Ⅴ))from water.Among these MOFs,MIL-101(Fe)exhibited the best adsorption capacities for both Sb(Ⅲ)and Sb(Ⅴ)(151.8 and 472.8 mg/g,respectively)which were higher than those of most adsorbents previously reported.The effect of steric hindrance was evident during Sb removal using the Fe-based MOFs,and the proper diameter of the smallest cage windows/channels should be considered an important parameter during the evaluation and selection of MOFs.Additionally,the adsorption capacities of MIL-101(Fe)for Sb(Ⅴ)decreased with increasing initial p H values(from 3.0 to 8.0),while the opposite trend was observed for Sb(Ⅲ).Chloride,nitrate and sulfate ions had a negligible influence on Sb(Ⅴ)adsorption,while NO3-and SO42-improved Sb(Ⅲ)adsorption.This result implies that inner sphere complexes might form during both Sb(Ⅲ)and Sb(Ⅴ)adsorption.
We explored the feasibility and removal mechanism of removing 2-chlorobiphenyl（2-Cl BP）from soil–water system using granular activated carbon（GAC） impregnated with nanoscale zerovalent iron（reactive activated carbon or RAC）.The RAC samples were successfully synthesized by the liquid precipitation method.The mesoporous GAC based RAC with low iron content（1.32%） exhibited higher 2-Cl BP removal efficiency（54.6%） in the water phase.The result of Langmuir–Hinshelwood kinetic model implied that the different molecular structures between 2-Cl BP and trichloroethylene（TCE） resulted in more difference in dechlorination reaction rates on RAC than adsorption capacities.Compared to removing2-Cl BP in the water phase,RAC removed the 2-Cl BP more slowly in the soil phase due to the significant external mass transfer resistance.However,in the soil phase,a better removal capacity of RAC was observed than its base GAC because the chemical dechlorination played a more important role in total removal process for 2-Cl BP.This important result verified the effectiveness of RAC for removing 2-Cl BP in the soil phase.Although reducing the total RAC removal rate of 2-Cl BP,soil organic matter（SOM）,especially the soft carbon,also served as an electron transfer medium to promote the dechlorination of 2-Cl BP in the long term.
