| Sulfanilamide antibiotics（SAs）in wastewater and surface water posed potential threat to ecosystem balance and human health,which were ecotoxic and could induce the generation of resistance genes.The adsorption process has great potential to efficiently remove SAs from water,but mg·L-1 concentration level of natural organic matter（NOM）in wastewater/actual water could strongly interfere the adsorption of SAs.Therefore,the synthesis of highly selective adsorbent was the key of achieving efficient antibiotic adsorption removal.The adsorption of pollutants was limited by the pore size of adsorbent.Based on the molecular size difference between NOM and SAs,efficient selective adsorption of SAs could be achieved through the pore size-exclusion effect.However,the adsorbents displayed complex micro/mesoporous structures with a wide pore size distribution.The quantitative relationship between the pore size/pore structure of adsorbents and the selective SAs adsorption performance is still unclear.Based on the excellent structural tunability of mesoporous carbon materials prepared by template method,this study took the precise regulation of mesoporous carbon pore size/pore structure as the breakthrough point,selected sulfamethoxazole（SMX）and humic acid（HA）as representative SAs/NOM,and explored the influence of mesoporous carbon pore size/pore structure on SMX adsorption performance through adsorption kinetics and adsorption isotherms.The adsorption mechanism of SMX on mesoporous carbon was elucidated.On this basis,the selective adsorption performance was evaluated by capacity retention rate which was the ratio of SMX adsorption capacity before and after adding HA.The quantitative relationship between mesoporous carbon pore size/pore structure and SAs selective adsorption performance was investigated by adsorption kinetics experiments under the interference of different concentration/molecular weight of HA,which provided theoretical support for the design of highly selective SAs adsorbent.The results were as follows:（1）Based on the hard template method,the pore size of ordered mesoporous carbon（OMCs）was quantitatively regulated by changing the boric acid concentration in the precursor solution.The pore sizes of OMCs were 4.8 nm（OMC-0）,6.2 nm（OMC-1）and 8.1nm（OMC-2）,respectively.Based on the hard template/soft template method,the quantitative control of mesoporous carbon（MCs）pore structure was realized by changing the type of template.The pore structures of MCs were interconnected vesicle（MC@Si O2 NPs）,independent column（FDU-15）,multidirectionally connected pore（MC@MCM-48）,and interconnected column（OMC@SBA-15）,respectively.（2）As the pore size of OMCs decreased from 8.1 nm to 4.8 nm,the adsorption capacity gradually increased（OMC-0>OMC-1>OMC-2）,but the adsorption rate did not change.The pseudo-second-order adsorption rate constant（K2）of the three OMCs was about 4.1×10-3 g·mg-1·min-1.With the change of pore structure,the adsorption capacity of MCs was ranked as OMC@SBA-15>MC@Si O2 NPs>MC@MCM-48>FDU-15.Disordered or independent pore channels are not conducive to mass transfer and adsorption of SMX.The K2order of MCs is:OMC@SBA-15(5.2×10-3 g·mg-1·min-1)>FDU-15(3.6×10-3g·mg-1·min-1)>MC@MCM-48(2.5×10-3 g·mg-1·min-1)≈MC@Si O2 NPs(2.4 x 10-3g·mg-1·min-1).Due to the porous of OMCs and MCs,the diffusion process of SMX on OMCs and MCs could be divided into three stages:liquid film diffusion,pore diffusion and adsorption equilibrium stage.The adsorption mechanism of SMX on mesoporous carbon adsorbents mainly included hydrogen bonding,pore filling andπ-πconjugated interaction.（3）As the concentration of HA increased from 1 mg·L-1 to 4 mg·L-1,the interference effect was gradually enhanced,and the adsorption capacity of OMCs was gradually decreased.Under the interference of 1-4 mg·L-1 HA,the smallest pore size of OMC-0 exhibited the strongest size-exclusion effect with the highest SMX adsorption capacity retention rate of70.3%-84.4%,much higher than 54.4%-69.1%of OMC-1 and 50.0%-58.9%of OMC-2.The strongest size-exclusion effect alleviated the interference of HA on the adsorption process.The K2(4.1-3.7×10-3 g·mg-1·min-1)of OMC-0 was significantly faster than that of OMC-1(3.9-3.4×10-3 g·mg-1·min-1)and OMC-2(3.7-3.1×10-3 g·mg-1·min-1).Moreover,with the increase of HA molecular weight from<30 k Da to>100 k Da,the size-exclusion effect of three OMCs was also effectively strengthened,thus achieving a rising retention rate from54.8%-68.3%to 78.7%-100.0%.Meanwhile,OMC-0 completely eliminated the interference of>30 k Da HA,leading to an ultrahigh capacity retention rate of 96.4%-100.0%.Under the interference of 1-30 mg·L-1 HA,OMC@SBA-15 and MC@MCM-48 exhibited similar anti-interference performance 41.0%-91.0%and 41.2%-86.4%,respectively.Compared with the other two,FDU-15 showed poor anti-interference performance with the SMX capacity retention rate of 34.1%-88.8%.Under the interference of 1-5 mg·L-1 HA,the large pore size of MC@Si O2 NPs（～12.1 nm）resulted poor anti-interference performance with the SMX capacity retention rate of 60.9%-85.9%,which was lower than that of OMC@SBA-15 and MC@MCM-48.However,at a high concentration of 15-30 mg·L-1 HA,the high external specific surface area(463 m2·g-1)of MC@Si O2 NPs alleviated the HA interference,and the capacity retention rate was the highest among the four（49.3%-54.7%）. |
