Remoção de diclofenaco do meio aquoso utilizando sementes de Moringa oleífera

Abstract

In this work, Moringa oleifera seeds were investigated for the removal of the pharmaceutical diclofenac sodium (DCF) from aqueous solutions. The biomass was initially characterized by several techniques including elemental analysis (CHNS), midinfrared spectroscopy (FT-MIR), thermogravimetric analysis (TGA), and scanning electron microscopy (MEV). The specific surface areas as well as the average diameter of particles and pH at the point of zero charge (pHPZC) were also determined. Subsequently, the adsorption capacity of Moringa oleifera was investigated. The high in efficiency liquid chromatography (HPLC-UV) was used as the determination DCF. The parameters such as adsorbent mass, pH, contact time and concentration of DCF were previously optimized in order to be able to follow this process. The chromatographic parameters for isocratic elution were: mobile phase flow rate: 1.5 mL min-1; mobile phase: acetonitrile: 0.7molL-1 acetic acid; ratio of mobile phase: (50% acetonitrile and 50% acidified water); wavelength: 282 nm; retention time: 9.6 minutes. The results obtained for assessment of removal were: mass of adsorbent 500.00 mg, 30 minutes of contact time and pH 5.00. The pseudo order kinetic model was described the speed of the adsorption process, obtaining a correlation coefficient to 0.999. Regarding the balance of the process, the two models analyzed isotherm (Langmuir and Freundlich) had a very close correlation coefficient values, which were 0.9989 for the Langmuir isotherm, and the adsorption of the DCF Moringa oleifera presented a QMfx value of 0.37 mg g- and the Freundlich isotherm showed a value of r of 0.9976 and its constants were KF equal to 8.32 g L-1 en equal to 1.88.. The proposed procedure was applied to DCF removal in water samples obtained 100% of removal efficiency.