Enhanced Adsorption of Methylene Blue and Congo Red from Aqueous Solutions by MCM-41/HKUST-1 Composites

Abstract

Impregnation of mesoporous silica MCM-41 on metal organic framework type HKUST-1 or often called CuBTC (BTC = 1,3,5benzenetricarboxylate) has been successfully carried out by solvothermal methods in a solvent mixture of water, ethanol and N,Ndimethylformamide (DMF). The XRD patterns of the obtained solids showed that MCM-41/HKUST-1 composites had the same crystalline phase as pure as HKUST-1. SEM images revealed that the impregnation of the mesoporous silica to HKUST-1 did not alter the surface morphology of the original HKUST-1, which had octahedral shapes. In addition, the thermal stability of the MCM-41/HKUST-1 composites reached 302 °C, increased by 292 °C in comparison to the HKUST-1, even though the impregnation process resulted in a decreased in the specific surface area of the composites. Furthermore, MCM-41/HKUST-1 composites showed outstanding performance as adsorbent of methylene blue and Congo red in aqueous solutions. Results of adsorption studies showed that a pseudo-second order kinetics and Langmuir isotherm were observed for both types of dyes.

Metal organic framework composite based on CuBTC/SPION for application in methylene blue adsorption

“…[32,33] However, poor stability and recoverability in aqueous media have prompted research into CuBTC composite materials to enhance their practical use. Therefore, various composites on CuBTC have been described in the literature to improve adsorbent performance, including inorganic hybrids such as mesoporous silica MCM-41 on a metal-organic framework like HKUST-1, [34] Al-modified MCM-41/HKUST-1, [35] or magnetic variants like Fe 3 O 4 /HKUST-1/GO [33] making it possible to use MOF composites in ion exchange, catalysis, and adsorption. [36] Hybrids can increase the pore size, and surface area, improve the stability in an aqueous media, or enhance the functionality of the material.…”

Synthesis, characterization of Lanthanum (III) / Terephthalate metal-organic framework, and potential use for Removal of anionic and cationic exchange contaminants

“…The dyes presence as pollutants in the environment is wasted, but most of these components are also hazardous and very toxic [14,15]. Azo dyes are used in textiles, paper, cosmetics, and different industries [16], such as (MB) and (CR) [15], which can be dangerous not only for the environment but also for animals and humans [16].…”