The Use of Copper Terephthalate for the Determination and Separation of Organic Dyes via Solid-Phase Extraction with Spectrophotometric Detection

Abstract

In this work, a metal–organic framework (MOF), copper benzene dicarboxylate (Cu-MOF), was tested for the adsorptive recovery of organic dyes (Sunset Yellow FCF, Tartrazine, Orange II, and Methyl Orange) from aqueous solutions. Studies were also carried out to determine the effects of various parameters, and isothermal and kinetic models were proposed. The adsorption capacity of Cu-MOF was much higher than that of activated carbon. The experimental data are best described by the Langmuir isotherm model (R2 > 0.997) and show the ability of Cu-MOF to adsorb 435 mg/g of the dye under optimal conditions. The study of the kinetics of the dye adsorption process followed a pseudo-second-order kinetic model indicating the coexistence of physical and chemisorption, with diffusion within the particles being the rate-limiting step. Thermodynamic studies were also carried out, and they led to the conclusion that the adsorption of the dye was a feasible, spontaneous, and exothermic process (−25.53 kJ mol−1). The high organic dye recovery shows that Cu-MOF can be used as an efficient and reusable adsorbent for the extraction of dyes from aqueous solutions. These studies may lead to economic interest in this adsorbent material for environmental purposes.

Keywords

• metal–organic framework
• organic dye
• adsorption
• solid-phase extraction
• separation