Development of highly porous activated carbon from Jacaranda mimosifolia seed pods for remarkable removal of aqueous-phase ketoprofen

In this work, a high porous activated carbon from Jacaranda mimosifolia was developed and employed for ketoprofen adsorption. After the pyrolysis process at 973.15 K, the material presented cavities with different sizes allocated on the particle surface. The material presented a pH at the point of zero charge of 4.1 with the best adsorption at pH 2. The best adsorbent dosage was 0.72 g L−1, corresponding to a removal of 96%. The system reached the adsorption equilibrium after 120 min and was described by the linear driving force model. The isotherms revealed that the adsorption capacity decreased with the temperature and followed the Langmuir model, with a maximum adsorption capacity of 303.9 mg g−1. This high capacity can be associated with the high surface area (928 m2 g−1) and pore volume (0.521 cm3 g−1) values. The thermodynamic values indicated that the adsorption system is spontaneous and exothermic. The enthalpy value indicates that the interactions between the adsorbent and adsorbate are physical. Regeneration tests showed a decreasing percentage of removal of 7.86% after 5 cycles. Finally, the adsorbent showed efficiency when treating a simulated effluent containing drugs and inorganic salts, showing the removal of 71.43%

Adsorption of ketoprofen and paracetamol and treatment of a synthetic mixture by novel porous carbon derived from Butia capitata endocarp

In this work, endocarp of the species Butia capitata was employed as precursor material to prepare a novel activated carbon with intrinsic properties to remove ketoprofen and paracetamol from water efficiently. The activated carbon presented a predominantly microporous structure, with an average pore diameter of 1.23 nm, a total pore volume of 0.449 cm3 g−1, and a high specific surface area, 820 m2 g−1. The adsorption kinetics showed a rapid initial decay for both pharmaceuticals, with the system entering equilibrium after 120 min for ketoprofen and 180 min for paracetamol. The pseudo-second-order model presented the best fit for ketoprofen and the Elovich model for paracetamol. The adsorption equilibrium data show that temperature can increase or decrease the adsorption capacity, being found a maximum adsorption capacity of 108.79 and 100.60 mg g−1 for the ketoprofen and paracetamol, respectively. The Freundlich and Langmuir models presented the best statistical adjustments for the adsorption of ketoprofen and paracetamol, respectively. The thermodynamic analysis confirmed an endothermic process for ketoprofen (ΔH0 = 11.98 kJ mol−1) and exothermic for paracetamol (ΔH0 = -13.37 kJ mol−1). The recycle tests revealed that the adsorbent has an average decrease for removal percentage of only 1.88 % for ketoprofen and 1.57 % for paracetamol. Estimations costs indicate that the price of 1 kg of activated carbon costs is 2.39 USD at minimum. Last, the material presented a highly efficient adsorptive activity to treat a synthetic mixture containing several pharmaceutical compounds and salts, reaching 84.82% removal

Residual peel of pitaya fruit (Hylocereus undatus) as a precursor to obtaining an efficient carbon-based adsorbent for the removal of metanil yellow dye from water

The pitaya peel (Hylocereus undatus) was carbonized in the presence of ZnCl2 to obtain a carbon-based adsorbent to remove the Metanil Yellow dye (MY) from colored waters. The characterization techniques confirmed that the material had morphological changes with the appearance of new irregularities and cavities. Besides, the alternative adsorbent was formed mainly by carbon and functional groups characteristic of lignin and cellulose. Isothermal and kinetic studies were carried out at the natural pH of the solution at a dosage of 0.4 g L−1. The Langmuir model demonstrated the best adjustment of the equilibrium isotherms of the system, reaching the maximum adsorption capacity of 144.07 mg g−1 at 298 K. The thermodynamic behavior indicated that it is a spontaneous and favorable process of an exothermic nature (ΔH0=−34.02 kJ mol−1), consistent with a mechanism involving electrostatic interactions. The MY concentration influenced the kinetic. The homogeneous surface diffusion model (HSDM) showed good statistical adjustment to the kinetic values, showing a slight increase in the diffusivity coefficient from 2.4 × 10−9 to 4.5 × 10−9 cm2 s−1 with the increased MY concentration. The material application in a mixture containing several dyes and salts in the circumstances close to the real ones showed removal of 82.5%. The adsorbent could be regenerated and used 12 times. Therefore, it can be concluded that the pitaya fruit residual biomass can be used as a precursor for preparing carbon-based adsorbents. The adsorbent, in turn, is a promising alternative in the treatment of MY dye and mixtures of organic molecules

Powdered biosorbent from pecan pericarp (Carya illinoensis) as an efficient material to uptake methyl violet 2B from effluents in batch and column operations

The application of dyes in industrial processes has become a growing preoccupation due to the high quantities of colored effluents generated, which need previous treatment before being discarded in water bodies. A powdered biosorbent was then prepared from pecan pericarp and HCl, in order to treat colored effluents containing the dye methyl violet 2B (MV2B) using batch and fixed-bed operation modes. The new biosorbent, so-called powdered pecan pericarp (PPP), was characterized by functional groups related to cellulose, lignin, and hemicellulose. In addition, the material was composed of particles with different sizes, amorphous structure, and rugous surface. The best pH for MV2B biosorption on the PPP was 8.5. The kinetic profile was better described by the general order model, being the equilibrium rapidly reached in the first 5 min for different initial concentrations MV2B. The equilibrium curves were better described by the Langmuir model, indicating homogenous biosorption. The maximum biosorption capacity of 642 mg g−1 was reached at 328 K. Biosorption was favorable and endothermic. PPP has removed 94.1% of color in the simulated effluent. The fixed-bed assays revealed that the column packed with PPP could operate during 52.5 h with a height of 25 cm. The Thomas, Bohart-Adams, and Yoon-Nelson models were suitable to describe the dynamic curves. Therefore, PPP can be used as an efficient and fast biosorbent to treat textile effluents containing MV2B dye

Application of araçá fruit husks (Psidium cattleianum) in the preparation of activated carbon with FeCl3 for atrazine herbicide adsorption

The residual husks of the edible fruits of Psidium cattleianum were carbonized with FeCl3 as an activating agent and used as an adsorbent to remove the toxic herbicide. After the carbonization step, changes in the material’s structure were found. Activated carbon showed characteristics of microporous materials with a pore volume of 0.280 cm3 g−1 and surface area of 431 m2 g−1. Micrographs revealed the emergence of new cavities with a uniform and circular shape. The FTIR spectra showed the disappearance of some bands, remaining bands belonging to functional groups containing carbon, oxygen, and hydrogen. The XRD patterns confirmed the amorphous structure of the material even after the carbonization step, composed of amorphous graphitic carbon. EDS analysis showed that the carbon percentage increased and the oxygen decreased after the carbonization. The experiments were performed at neutral pH using 1 g L−1 of adsorbent. In equilibrium isotherms, the temperature played a considerable role in the adsorption capacity, increasing from 26.39 mg g−1 to 35.67 mg g−1 when the temperature varied from 298 to 328 K. The Liu isotherms were the ones that best fit the isotherm data. The changes in the adsorption enthalpy were endothermic (ΔH° 129.5 kJ mol−1). The general order kinetic model was the most adequate for kinetic data, presenting the lowest values of the Bayesian Information Criterion. Thus, activated carbon developed from the residues of the “araça” fruit showed promise in removing atrazine from aqueous solutions, with the great advantage of its high efficiency under neutral pH solutions and mild temperatures