Activated Olive Stones as a Low-Cost and Environmentally Friendly Adsorbent for Removing Cephalosporin C from Aqueous Solutions

Abstract

In this paper, we describe the removal of cephalosporin C (CPC) from aqueous solutions by adsorption onto activated olive stones (AOS) in a stirred tank. For comparative purposes, several experiments of adsorption onto commercial granular activated carbon were carried out. A quantum study of the different species of cephalosporin C that, depending on the pH, exist in aqueous solution pointed to a favorable mass transfer process during adsorption. Activated olive stones were characterized by SEM, EDX and IR techniques and their pHzc was determined. A 10−3 M HCl cephalosporin C solution has been selected for the adsorption experiments because at the pH of that solution both electrostatic and hydrogen bond interactions are expected to be established between the adsorbate and the adsorbent. The adsorption process is best described by the Freundlich isotherm model and the pseudo-second-order kinetic model, while the adsorption mechanism is mainly controlled by film diffusion. Under the conditions studied, the adsorption process is of a physical nature, endothermic and spontaneous. Comparison of the adsorption results obtained in this paper with those of other authors shows that the efficiency of AOS is 20% of that of activated carbon but 65% higher than that of the XAD-2 adsorbent. Considering its low price, abundance, easy accessibility and eco-compatibility, the use of activated olive stones as adsorbents for the removal of emerging pollutants from aqueous solutions represents an interesting possibility from both the economic and the environmental points of view.

Super-Adsorbent Hydrogels for Removal of Methylene Blue from Aqueous Solution: Dye Adsorption Isotherms, Kinetics, and Thermodynamic Properties

“…A pseudo-first-order model is based on the hypothesis that the rate of solute adsorption with time is proportional to the saturated concentration and number of unoccupied sites, whereas a pseudo-second-order model assumes that the adsorption rate is controlled by chemical adsorption through sharing or exchange of electrons between the adsorbent and adsorbate. The Elovich model, on the other hand, predicts multilayer adsorption where the rate of adsorption of solute decreases exponentially with the increase in the amount of adsorbed solute [67,68]. All three models are reaction-based models while the Boyd model is diffusion-based, which assumes that the boundary layer surrounding the adsorbent has the greatest effect on diffusion of solute and film diffusion is a rate limiting step during the initial phase of adsorption, followed by intraparticle diffusion [67,69,70].…”

Methylparaben Adsorption onto Activated Carbon and Activated Olive Stones: Comparative Analysis of Efficiency, Equilibrium, Kinetics and Effect of Graphene-Based Nanomaterials Addition

“…Crushed olive stones were washed with distilled water and dried at 60 • C in an oven. In order to increase their active surface area, remove soluble components (tannins, resins, reducing sugars and dyes) and generate oxygenated functional groups (carboxyl, phenol, ketone and lactone), the olive stones were subjected to an activation process consisting of calcination at 300 • C for 3 h in a closed muffle furnace and subsequent treatment with 1 M HCl at room temperature (25 ± 2 • C) for 8 h [27,28]. Finally, the activated olive stones (AOS) were filtered, washed thoroughly with distilled water, dried at 100 • C for 24 h and stored in a desiccator.…”

“…The commercial activated carbon used has a zero charge point of 4.7 [56], which means that it will have a positive charge at pH values below 4.7 and a negative charge at higher pH values. Activated olive stones have a zero charge point of 3.5 [28], being positively charged at pH values below 3.5 and negatively charged at pH values above 3.5. With regard to the functional groups present on the surface of these adsorbents, the presence of carboxyl, phenol, anhydride, lactone, quinone and ether groups has been described in both activated carbon [57,58] and activated olive stones [28,59].…”

Analytical Determination of Cephalosporin Antibiotics Using Coordination Polymer Based on Cobalt Terephthalate as a Sorbent

“…Due to the wide and strong spectrum of bactericidal action of cephalosporins, their production and use in clinical practice is constantly growing. Global production of cephalosporin antibiotics was USD 13.69 billion in 2019 and will reach USD 16.87 billion by 2027 [ 6 ]. The most common uses of cephalosporins are aquaculture and human and veterinary medicine [ 7 , 8 , 9 , 10 , 11 ].…”