A review of the antibiotic ofloxacin: current status of ecotoxicology and scientific advances in its removal from aqueous systems by adsorption technology

It is estimated that the growth of the population, the augmented expectancy of life, and the emergence of new pandemics will significantly increase the consumption of pharmaceutical drugs in the coming years. Due to its high efficiency, the group of fluoroquinolones, where the antibiotic ofloxacin hydrochloride (OFL) is found, is widely used to combat bacterial infections in humans and animals. The big problem is concentrated in the effluents generated by industries and hospitals. Additionally, most of the drug is not absorbed by the body and is released directly into domestic effluents. On the other hand, treatment stations have removal limitations for small concentrations. This review analyzed all adsorbents developed and used in OFL removal, listing the main parameters influencing the process. In the end, the other existing technologies in the literature and the gaps and future prospects were described. OFL adsorption in most studies occurs under basic conditions (pH between 6.5 and 8). The increase in concentration provides an increase in adsorption capacity. The adsorbents analyzed showed moderate kinetics, reaching equilibrium before 250 min for most studies. The pseudo-second-order model showed the best statistical fit. In most of the studies, the increase in temperature (313, 315, and 328 K) favored the adsorption of OFL. The Langmuir monolayer model represented most of the isothermal studies. The adsorption capacity varied from 3702 to 0.3986 mg g−1. In this aspect, factors such as OFL concentration and textural characteristics of the adsorbent exerted great influence. The thermodynamic parameters were compatible with the isothermal data, where the endothermic nature of the studies was confirmed. Physical interactions (π-π stacking, H bonding, hydrophobic and electrostatic interactions) governed the main adsorption mechanism. Although some studies stated that chemosorption occurred, thermodynamic parameters cannot validate the same. Coexisting ions in the solution can positively and negatively influence OFL adsorption. The listed studies are all applied to batch processes, where fixed bed studies should be better explored. From this review, it can be concluded that adsorption is a promising technique for OFL removal. However, it is extremely necessary to break the laboratory scale barrier and analyze possible conditions for applying these materials in treating real effluents together with combining technologies

Production of adsorbent for removal of propranolol hydrochloride: use of residues from Bactris guineensis fruit palm with economically exploitable potential from the Colombian Caribbean

The production and consequently the consumption of the pulp of the fruit of the palm tree Bactris guineensis occurs extensively in Colombia. The majority of the fruit is formed by waste (peel and core), producing high residual biomass. Thus, it is necessary to find a practical utilization of these peels, making the production and consumption of the fruit of the palm tree Bactris guineensis highly sustainable. This study produced activated biochar chemically activated using ZnCl2 and utilized it as an effective adsorbent. The high micropollutant uptake is because of the high porosity and good specific surface area (SBET = 625 m2 g−1). Under basic conditions, propranolol adsorption was favored for an adsorbent dosage of 0.7 g/L. The adsorbent showed fast kinetics, with the equilibrium influenced by the concentration. Avrami's model showed a satisfactory fit having a t0.95 ranging from 47.8 to 179.3 min. Equilibrium data were best adjusted to the Liu isotherm model. The values of Qmax increased with the temperature, reaching up to 161.3 mg g−1 (45 °C). The thermodynamic data showed ΔG° < 0 for 298–328 K (adsorption process favorable) ΔH°= + 7.403 kJ mol−1 (endothermic; magnitude compatible with physical adsorption), and ΔS°= +115.2 J K−1 mol−1 (releases of water molecules of the adsorbate before it being adsorbed in the carbon surface). The biochar chemically activated with ZnCl2, produced from the leftover peels of Colombian palm fruits, is therefore inferred to be a promising option as an adsorbent for the treatment of effluents containing the medication propranolol hydrochloride

Removal of enalapril maleate drug from industry waters using activated biochar prepared from Butia capitata seed. Kinetics, equilibrium, thermodynamic, and DFT calculations

Porous biochar was fabricated from Butia capitata (Bc) seed, which was used to uptake enalapril maleate from synthetic wastewater. Activated biochars were fabricated by blending Bc and ZnCl2 at 1:1 (BcB-1.0) or 1:1.5 (BcB-1.5) proportions and furtherly pyrolyzed at 600 °C. The elemental analysis, Boehm titration, hydrophobic balance ratio, FTIR, TGA, and N2 isotherm characterized the carbon-based materials. They presented a hydrophilic behavior with diverse polar groups on their surface. BcB-1 and BcB-1.5 biochars have a total pore volume of 0.392 and 0.492 cm3 g−1 and a surface area of 1267 and 1520 m2/g, respectively. The kinetics and isothermal data were adequately adjusted to the fractal-like pseudo-second-order and Liu models. The employment of BcB-1.0 and BcB-1.5 for treating synthetic wastewater containing high levels of pollutants had elevated efficiency in their removals (up to 99.06%). We also conducted a DFT computational study, density functional theory (DFT), to examine the interactions between enalapril and a graphitic domain of biochar by using these calculations, the most stable configuration presented interaction energy of −88.7 kJ mol−1 implies a face-to-face π–π stacking interaction involving the enalapril phenyl segment and an aromatic ring of the graphitic domain, as well as London dispersion arising from the proximity of ethoxy/pyrrolidine to biochar carbon atoms, with interatomic distances of 3.31 Å for the former and 3.60 Å /3.48 Å for the latter. Also, the DFT calculations agreed with the thermodynamic data calculated from the isotherms (283–318 K)