| Abstrakt: |
In the present study, Dialiumguineensefruit shells as biosolid waste were used for the preparation of untreated (UD) and simple chemically treated (TD) solid adsorbents. In the current work, a useful solid adsorbent from solid agricultural waste was produced for use in environmental applications. Both of UD and TD were characterized using nitrogen gas adsorption at − 196 °C, XRD (X-ray diffraction spectra), TGA (thermogravimetric analysis), point of zero charges (pHPZC), SEM (scanning electron microscopy), TEM (transmission electron microscope), and ATR-FTIR (attenuated total reflection Fourier transform infrared spectroscopy). TGA showed the thermal stability of the two solid samples up to nearly 25 °C while pHPZCwas found to be 7.1 and 6.6 for UD and TD, respectively, with amorphous structures as indicated by XRD pattern. SEM and TEM analyses prove the structure cracking and pore creation with chemical treatment in the case of TD. The treated sample exhibited advanced textural structure than the untreated one with 15.4 m2/g, 0.0107 cm3/g, and 1.34 nm as surface area, total pore volume, and pore radius, respectively. Adsorption capacity of the two samples was investigated via methylene blue adsorption under different applications conditions considering kinetic and thermodynamic studies. Adsorption of MB onto UD and TD samples fit well Langmuir, Temkin, Dubinin-Radushkevich, pseudo-first order, and Elovich models. TD exhibited the maximum Langmuir adsorption capacity at 45 °C (85.84 mg/g). Thermodynamic parameters confirm the spontaneous, endothermic, and physisorption of MB onto the investigated solid samples. Desorption and reusability studies showed that HCl (1.0 mol/L) exhibited the maximum desorption efficiency (98.3%), while TD adsorption efficiency decreased by only 9.15% after six cycles of adsorption and desorption studies. |
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