Fabrication of MIL-53(Al) based composites from biomass activated carbon (AC) for efficient p-nitrophenol adsorption from aqueous solution

The aim of this study was to develop a class of novel MIL-53(Al) based composite with high phenolic compound adsorption capacity to treat highly toxic phenolic wastewater. MIL-53(Al)@AC-x composites with different AC loading (x) were constructed by combining MIL-53(Al) with cheap biomass AC derived from cheap rice husk. The adsorbents were characterized by various methods. The results showed that the surface area and pore volume of all MIL-53(Al)@AC-x composites increased remarkably, which are much higher than those of pristine AC and MIL-53(Al). The p-nitrophenol adsorption rate of MIL-53(Al)@AC-10 was higher than pristine MIL-53(Al) by 36%. The adsorption performance decreased in the order of MIL-53(Al)@AC-10 > MIL-53(Al)@AC-15 > MIL-53(Al)@AC-5 > MIL-53(Al). The maximum adsorption capacity for p-nitrophenol of MIL-53(Al)@AC-10 reached 250 mg.g−1, which are higher than the data reported in most literature. The fabrication of AC into MIL-53(Al) is a promising method to obtain a composite with high adsorption capacity and stability. The adsorption kinetics and isotherms fitted well with pseudo-second-order model and Langmiur model. The adsorption is mainly through the π-π and hydrogen bond interactions, and hydrophobic effect.