| Abstrakt: |
Date palm spathes were selected as a raw material due to their high cellulosic content and their abundance in Algeria with no cost. There is only one earlier study on AC production from date palm spathes using microwave preparation. By valorizing this agricultural waste, this research aims to prepare a high-performance activated carbon from date palm spathes to effectively remove Congo red from an aqueous solution. Activated carbon (AC) was prepared from date palm spathes via phosphoric acid activation at 450 °C. The acid was mixed with date palm spathes at different mass percent (30, 60, 100, and 150%) and AC30, AC60, AC100, and AC150 were produced. ACs produced were examined for the surface area and porosity, SEM, EDS, FTIR, XPS, CHN, XRD, and the adsorption of Congo red (CR), a known carcinogenic and mutagenic dye, from aqueous solution. Surface area of AC30, AC60, AC100, and AC150 is 925.8, 1207.9, 1441.5, and 1276 m2/g with surface microporosity domination. XRD shows an amorphous structure and a little degree of graphitization. Surface functional groups such as –OH, C-O, C = O, and C–O–C were identified via FTIR and XPS analysis. The carbons used show an outstanding performance of CR removal. CR removal was high at low pH and increased ionic strength. CR adsorption is fast and follows pseudo-second-order model well. The activation energy values (> 42 kJ/mol) indicate chemical adsorption except for AC30. CR adsorption follows well the Langmuir adsorption model with AC150 showing an outstanding adsorption capacity of 1032 mg/g at a temperature of 50 °C and pH 7. Notably, this performance surpassed that of previously reported carbon-based adsorbents found in the literature. Thermodynamic parameters show that CR adsorption is in general endothermic, and spontaneous except for AC30 and AC100 at low temperatures. The preparation of ACs, in this study, has proven to possess high adsorption capacity and versatile applicability, making it an ideal material for wastewater purification purposes with broad practical applications. |
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