Characterization of Ziziphus lotus’ Activated Carbon and Evaluation of Its Adsorption Potential

Abstract

This study aims to prepare activated carbon from an interesting biomaterial, corresponding to the cores of Ziziphus lotus, for the first time to the best of our knowledge, according to a manufacturing process based on its chemical and thermal activation. These cores were chemically activated by sulfuric acid for 24 h and then carbonized at 500°C for 2 hours. The obtained activated carbon was characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and Brunauer–Emmett–Teller (BET) analysis. The adsorption of methylene blue (MB) on the activated carbon was evaluated, by Langmuir and Freundlich models examination, in order to explain the adsorption efficiency in a systematic and scientific way. Moreover, pseudo-first-order and pseudo-second-order kinetic models were used to identify the mechanisms of this adsorption process. The characterization results showed an important porosity (pore sizes ranging from 10 to 45 µm), a surface structure having acid groups and carboxylic functions, and a specific surface of 749.6 m2/g. Results of the MB adsorption showed that this process is very fast as more than 80% of MB is adsorbed during the first 20 minutes. In addition, increasing the contact time and temperature improves the MB removal process efficiency. Moreover, this adsorption’s kinetic modeling follows the pseudo-second-order model. Furthermore, data on the adsorption isotherm showed a maximum adsorption capacity of 14.493 mg/g and fit better with the Langmuir model. The thermodynamic parameters (∆G0, ∆S0, and ∆H0) indicate that the adsorption process is endothermic and spontaneous. Therefore, Ziziphus lotus can be used as a low-cost available material to prepare a high-quality activated carbon having a promising potential in the wastewater treatment.

Evaluation of Activated Carbons Prepared from Bioprecursors for the Removal of Cadmium and Chromium (VI)

“…Te process of preparation of activated carbon using the nucleus of Ziziphus lotus (NZL) and cofee grounds (GC) as raw materials follows several steps, according to Touzani et al [20,21]. Step 1: Te NZL and GC are washed, dried, and then crushed into fne particles; step 2: Chemical activation of the NZL and GC by sulfuric acid (H 2 SO 4 ) for 24 h; step 3: Te carbonization of the paste obtained after chemical activation is made at 500 °C for 2 h; and step 4: Te active carbons obtained are sieved with a sieve smaller than 100 μm.…”

“…Te results show that the adsorption capacity obtained in this study is comparable to that obtained in the previous work. Furthermore, it is important to point out that the biomaterials used in this study are very abundant, so Ziziphus lotus is a species found in several biotopes in arid and semiarid regions and occupies various geographical areas of Morocco [20]. Whereas, cofee grounds represent waste, resulting from cofee consumption, which can have a great added value.…”

Removal of methyl orange dye from aqueous solutions using three types of biological activated carbons: Comparative study

“…An adsorption process can be described by means of an adsorption isotherm. Such an isotherm is a curve that represents the relationship between the amount of solute adsorbed per unit mass of adsorbent (Touzani et al 2022) ,the curves are obtained from laboratory test results.…”