Solvothermal growth of the bimetal organic framework (NiFe-MOF) on sugarcane bagasse hydrochar for the removal of dye and antibiotic

In this study, the bimetal organic framework incorporated on the sugarcane bagasse hydrochar (AHC) surface (NiFe-MOF@AHC) composite was prepared using a solvothermal method. The preparation parameters (concentrations of Ni(NO3)(2), FeCl3, H4BTeC, and reaction time) were optimized via the response surface methodology-central composite design (RSM-CCD) for the high adsorption removals of the large-sized pollutants (crystal violet (CV) dye and tetracycline (TC)). The optimized NiFe-MOF@AHC (NiFe(op)AHC) was characterized with dual three-dimensional (3-D) structures of intertwined nanosheets porous networks and hexagonal spindleshaped crystals with mesopore structures 2.3 times higher than the surface area of AHC, ample carboxylic and metal-carboxylate groups, and high thermal stability at a wide temperature range (0-800 degrees C). The NiFe(op)AHC composite adsorption removal of both CV dye and TC demonstrated a fast removal rate, primarily by chemisorption. The maximum adsorption removal (Q(max)) of NiFe(op)AHC for CV dye (395.9 mg g(-1)) was 1.5 times lower than that of AHC, but the removal of TC (568.1 mg g(-1)) was 2.7 times higher than that of AHC. The hydrogen bonding, pi-pi or pi-EDA interactions, surface complexation, and acid-base interactions might play roles as the dominant mechanism for the removal of the CV dye/ TC. The regeneration studies showed that the removal of both CV dye and TC was reduced after the 1st cycle and maintained until the 4th cycle, demonstrating that the solvothermal growth of NiFe-MOF on AHC succeeded in producing a stable and recyclable adsorbent.

Automated summary

In this study, a NiFe-MOF@AHC composite was prepared using a solvothermal method and optimized for high adsorption removal of large-sized pollutants. The optimized composite showed a dual three-dimensional structure with high thermal stability and demonstrated fast removal rates for crystal violet dye and tetracycline. The dominant mechanisms for dye removal were hydrogen bonding, pi-pi interactions, surface complexation, and acid-base interactions. Additionally, the regeneration studies showed that the composite was stable and recyclable after multiple cycles.