The aim of this work was the technological characterization of sample fraction from Cubati region, Pedra Lavrada -Paraíba State, Brazil, in order to evaluate its further applications as drug adsorber and as oil drilling fluid. The sample had been properly processed and characterized by X-ray diffractometry, X-ray fluorescence spectroscopy,
Our previous work reported that palygorskite has potential for application as metal cations adsorbent due to its chemical and mineralogical properties. In this work, kinetic study and adsorption isotherms were performed in order to evaluate Pb (II) ions adsorption rate, maximum capacity and type of adsorption by using palygorskite as adsorbent. Adsorption tests were performed in batch, using pH of 5, 2 g of palygorskite, 40 mL of synthetic effluent solution and stirring for 1 hour. Kinetic experiments were performed using 34 mg L -1 of a lead synthetic effluent at same mass and pH conditions. Furthermore, after adsorption studies, the sample was characterized by X-ray fluorecence (XRF), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) coupled with Energy-dispersive X-ray spectroscopy (EDS) analysis, in order to verify and understand the interaction of lead ions in palygorskite. The results demonstrated that palygorskite presented an equilibrium time of 10 min with 99.14% of removal, following pseudosecond order kinetic. The maximum adsorption capacity was 21.65 mg g -1 and Gibbs' adsorption-free energy was -21.39 KJ mol -1 , with Langmuir model being the most suitable for adjustment of the data. Thus, its presence was confirmed by characterization techniques, indicating that the metal is distributed homogeneously on palygorskite surface, proving its efficiency as lead ions adsorbent.
The objective of this work was to investigate the adsorptive potential of a previously benefited and characterized brazilian montmorillonite sample, regarding amoxicillin trihydrate removal, a zwitterionic species, present in aqueous solutions. 500 mg capsule of antibiotic was properly characterized by XRD, FTIR, SEM/ EDS and surface charge measurement through Zeta potential. Amoxicillin aqueous solution and supernatants from adsorption essays were characterized by Molecular Absorption Spectrophotometry in Ultraviolet-Visible Region (UV/VIS), from 200 to 400 nm. Three investigative essays were performed, varying montmorillonite mass (0.050, 0.525 and 1.000 g) and contact time between substances (10, 95 and 180 min). Amoxicillin sample is crystalline, morphologically prismatic, essentially composed of carbon, nitrogen, sulfur, hydrogen and oxygen. Its zwitterionic character was confirmed by Zeta potential, presenting positive (pH 2 to 4), relatively neutral (pH 4 to 6), and negative (above pH 6) surface charges. Test results indicated that the highest removals (21.4 and 41.8 %) were for the largest clay mineral masses (0.525 and 1.000 g, respectively), with pHs close to amoxicillin pka 1 (2.68). Larger clay mineral masses have more adsorbent sites, which, associated with components opposite charges in desired pH range, promote a greater interaction. Thus, brazilian montmorillonite can promote amoxicillin removal from aqueous solutions.
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