Document Type : Original Article
Authors
1
Department of Organic Colorants, Institute for Color Science and Technology, Tehran, Iran.
2
Environmental Sciences Program, Faculty of Environment, University of Northern British Columbia, Prince George, British Columbia, V2N4Z9, Canada
3
Department of Inorganic Glaze and Pigments, Institute for Color Science and Technology, Tehran, Iran
4
Department of organic colourant, Institute for color science and technology, Tehran, Iran.
5
Department of Environmental Research, Institute for Color Science and Technology, Tehran, Iran
Abstract
The treatment of textile dyeing wastewater represents a remarkable environmental challenge, particularly with the use of natural dyes. Despite their more eco-friendly profile compared to synthetic counterparts, natural dyes contribute to pollution when not fully removed from effluents. Among various remediation techniques, adsorption stands out for its effectiveness, with metal-organic frameworks (MOFs) emerging as promising adsorbents due to their high adsorption capacities and structural stability. This study focuses on the application of a synthesized and characterized MIL-53 (Al) MOF for the adsorption of cochineal extract, a widely used natural red dye in the textile industry, especially handmade carpets. Employing Response Surface Methodology (RSM), we optimized dye removal under varying conditions such as adsorbent amount, temperature, contact time, and pH. Our findings revealed that adsorbent quantity notably influenced the adsorption efficiency, whereas temperature had the least impact, with the highest adsorption capacity observed at 60°C being 178.57 mg/g. Kinetic analyses indicated that the adsorption process conformed to the pseudo-second-order model, suggesting a physical adsorption mechanism, as further evidenced by an activation energy of 4.914 KJ/mol. Thermodynamic parameters, including changes in enthalpy (∆H°), entropy (∆S°), and Gibbs free energy (∆G°), were determined, revealing an endothermic reaction consistent with physical adsorption. The positive enthalpy change and the spontaneous nature of the process, inferred from a negative Gibbs free energy, underscore the potential of MIL-53 (Al) in efficiently removing cochineal dye from wastewater, contributing to the development of sustainable wastewater treatment strategies in the textile industry.
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