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In recent years, the contamination of the aquatic environment with antibiotics, including tetracyclines, has drawn much attention. Bottom ash (BA), a residue from the biomass power plant, was used to synthesize the magnetic mesoporous silica (MMS) and was utilized as an adsorbent for tetracycline (TC) removal from aqueous solutions. The MMS was cha...
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... adsorption kinetics test was conducted by adding 0.03 g of adsorbent to 10 mL of 100 mg/L TC solution at 45 • C. The adsorption data were fitted using three popular kinetic models, including the pseudo-first-order, pseudo-second-order, and Elovich models. The kinetic models are listed in the Equations (9)- (11) respectively, the corresponding nonlinear curves are shown in Figure 5, and Table 3 contains the estimated and shown kinetic parameters. For the pseudo-second-order and Elovich models, R 2 was considerably less than 1, and SSE, χ 2 were higher. ...
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... The enthalpy change (∆H) of the adsorption process, as determined by the pertinent thermodynamic parameters in Table 6, was G = 23.21 kJ/mol > 0, indicating that the reaction involving the spherical adsorption of tetracycline by a spherical adsorbent was a heat-absorption reaction process, and that raising the temperature was advantageous for the adsorption to proceed [33]. The adsorption process' entropy change (∆S) of S = 84.30 ...
The “sol–gel method” was used to prepare spherical chitosan-modified bentonite (SCB) hydrogels in this study. The SCB hydrogels were characterized and used as sorbents to remove tetracycline (TC) from aqueous solutions. The adsorbents were characterized by SEM, XRD, FTIR, TG, and BET techniques. Various characterization results showed that the SCB adsorbent had fewer surface pores and a specific surface area that was 96.6% lower than the powder, but the layered mesoporous structure of bentonite remained unchanged. The adsorption process fit to both the Freundlich model and the pseudo-second-order kinetic model showed that it was a non-monolayer chemical adsorption process affected by intra-particle diffusion. The maximum monolayer adsorption capacity determined by the Langmuir model was 39.49 mg/g. Thermodynamic parameters indicated that adsorption was a spontaneous, endothermic, and entropy-increasing process. In addition, solid–liquid separation was easy with the SCB adsorbent, providing important reference information for the synthesis of SCB as a novel and promising adsorbent for the removal of antibiotics from wastewater at the industrial level.
As a class of broad-spectrum antibiotics, tetracyclines find extensive use in human, veterinary, and aquacultural applications. Releasing tetracycline in the form of parent or derivative compounds into the aquatic environment is extremely dangerous to human health. This study investigates the ability of silica (SiO 2 ) extracted from Beureunut beach sand to remove tetracycline in an aqueous solution by combining adsorption and Fenton-like oxidation. The beach sand was used as a precursor, and it was reacted with a sodium hydroxide solution at 80 °C before being precipitated with sulfuric acid and dried. The extraction yielded 9.22 g of silica, which was then further characterized using Fourier transform infrared (FT-IR) spectroscopy. Prior to the adsorption test, the stability of tetracycline solution was evaluated at two different temperatures (11 °C and 30 °C). The findings of a 6-day stability test performed in water showed that tetracycline was more stable at 11 °C than at 30 °C. The adsorption capacity of silica was found to be 1.68 mg/g (17.00%) at 50 mg/L tetracycline concentration after 3 hours of contact time. Meanwhile, the adsorption method combined with the Fenton-like process increased the percentage of tetracycline removal from 17.00% to 56.32%. In conclusion, combining adsorption and Fenton-like processes provides an option for greatly increasing the ability of beach sand-based silica as a potential adsorbent to remove tetracyclines from water.
