RESUMO
The dataset reported in this article describes the adsorption isotherms of amoxicillin, ampicillin, and doripenem onto bentonite. Batch adsorption experiments were carried out on single antibiotic solutions with various dosage of bentonite across temperatures from 30 to 50 °C. The adsorbent loading dataset was later obtained by measuring the concentration of antibiotic solution at adsorption equilibrium via UV-Vis spectrophotometer. The dataset was also fitted using various isotherm models including Freundlich, Langmuir, Toth, Hill, and Dubinin-Radushkevich models to further analyze the adsorption behavior. On top of that, orthogonal regression was applied to avoid fitting biasness, whereby the fitting results revealed the highest adsorption capacities of 82.259 mg g-1 for amoxicillin, 78.851 mg g-1 for ampicillin, and 93.278 mg g-1 for doripenem using Langmuir model, which gave an accurate representation of the adsorption isotherm dataset that was consistent with the results of Toth and Hill model.
RESUMO
The removal of persistent antibiotics from the water bodies can be quite challenging. The present study deals with the removal of doripenem, one of the most stable and persistent antibiotics, from aqueous solution via adsorption technique using the low-cost structured alginate-immobilized bentonite (Alg@iB) beads which can be easily recovered after the process. Alg@iB possesses a porous interior and higher basal spacing compared with the acid-activated bentonite (iB). Its adsorption/desorption isotherm corresponds to type IV IUPAC classification and H4-type hysteresis loops, implying the presence of slit- or plane-shaped pores. The influences of four independent adsorption parameters, e.g., pH, initial doripenem concentrations (md), temperature (T), and Alg@iB loading (mc), on the removal rate of doripenem (Yd) are investigated. The maximum Yd (95.8% w/w) is obtained at pH = 5, mc = 1.4% w/v, T = 50 °C, and md = 250 mg/l. The study suggests that the adsorption of doripenem is spontaneous and endothermic. Further analysis using the multi-linear intra-particle diffusion (IPD) model indicates that the rate-governing step in this adsorption process is the physical diffusion from the bulk solution to the boundary layer of Alg@iB. However, the mechanism study also considers the chemical hydrogen binding between the hydronium ions of Alg@iB and hydroxyl groups of doripenem as one of the driving forces that promote adsorption. Alg@iB shows good reusability with Yd > 90% w/w up to five adsorption cycles. Based on the study, the Alg@iB beads exhibit excellent affinity to doripenem, indicating that an effective doripenem removal can be achieved using this sorbent material.
