Fabrication of CoFe-MOF materials by different methods and adsorption properties for Congo red

Abstract

Two kinds of metal organic framework (MOF) materials with Fe family elements as bimetallic center were synthesized via two different methods of one pot flux and MOF-on-MOF, respectively. The thermal stability and pore structure of the prepared MOF materials were different from each other. The prepared MOF materials were utilized to remove Congo red from aqueous solution to test their potential use in the treatment of wastewater containing organic dyes. Parameters affecting adsorption properties like contact time, initial concentration, ionic strength and pH of Congo red solution were systematically investigated. The adsorption capacity of CoFe-MOF material can reach as high as 1935.68 mg/g for Congo red and those of MOF materials with monometallic Fe and Co were 775.19 and 628.93 mg/g, respectively, indicating CoFe-MOF exhibited more defects leading to higher adsorption efficiency. It was surprising and interesting to find that the adsorption behaviors of the CoFe-MOF materials prepared by two different methods were different from each other. The prepared MOF materials can be used as potential candidates to treat organic dyes pollution especially anionic dyes from wastewater. This study provided guiding significance in the preparation of mixed MOF materials with more defects to be used in the remediation of effluents including organic dyes.