Preparation Of Activated Carbon-Amino-Modified Metal-Organic Framework Mil Composites And Their Phenolic Organic Adsorption Performance

Phenolic wastewater is widely sourced,extremely toxic to humans and the environment,and is recognized worldwide as a priority pollutant for control in water bodies.Phenolic compounds are structurally stable and are difficult to degrade hazardous substances.The adsorption method,which is simple in operation and low in cost,has become an important way to treat phenolic wastewater at present.Therefore,it is important to develop cheap and efficient adsorbents for the treatment of phenol-containing wastewater.In this paper,a series of low-cost,hydrophobic commercial activated carbon（AC）and biomass activated carbon（BAC）modified,-NH₂-functionalized（NH₂-）MIL-53（Al）@（B）（AC）-x adsorbents were prepared using metal-organic framework MIL-53（Al）as the parent body,and the performance of the adsorbents for the treatment of p-nitrophenol（PNP）in water was investigated.The following results were obtained:（1）BAC-modified MIL-53（Al）@BAC-x（x is the amount of BAC and addition）was prepared,and the effect of BAC loading on the adsorption performance of the adsorbent was investigated.The results showed that the BAC modification improved the specific surface area,pore capacity and adsorption performance of the adsorbent.the BAC modification significantly improved the adsorption performance of MIL-53（Al）.The adsorption capacity of PNP on MIL-53（Al）@BAC-10 was increased by 36%compared with that of unmodified MIL-53（Al）.The adsorption mechanism of PNP on MIL-53（Al）@BAC-x was mainlyπ-πand hydrogen bonding interactions and hydrophobic interactions.（2）Commercial AC-modified NH₂-MIL-53（Al）@AC-x（x is the AC incorporation amount）was prepared and the effect of AC loading on the adsorption performance of the adsorbent PNP was investigated.AC modification significantly improved the adsorption performance of NH₂-MIL-53（Al）on p-nitrophenol.The adsorption performance of all NH₂-MIL-53（Al）@AC-x was superior to that of the parent NH₂-MIL-53（Al）.The PNP removal ratio of NH₂-MIL-53（Al）@AC-10%（83.6%）was improved by 40.1%compared to that of unmodified NH₂-MIL-53（Al）（59.4%）.（3）The-NH₂-based functionalized NH₂-M（Al）@AC and NH₂-M（Al）@BAC composites were prepared from low-cost commercial AC and biomass carbon BAC,respectively.The effect of-NH₂groups on the adsorption performance of the adsorbents on PNP was investigated,and the adsorption mechanism was analyzed by DFT theoretical calculations.The results showed that the introduction of-NH₂groups could increase the mesopore volume of the composites,which was beneficial for mass transfer and full utilization of active sites.Compared with MIL-53（Al）@AC and MIL-53@BAC,the-NH₂tapped NH₂-MIL-53（Al）@AC and NH₂-MIL-53@BAC adsorbents both exhibited higher PNP adsorption capacity and lower activation energy.DFT calculations showed that the-hydrogen bonding between the NH₂group and-NO₂and the base-acid interaction between the-NH₂group and the-OH group of PNP are the main adsorption mechanisms between the-NH₂group and PNP in the adsorbents.