Graphene oxide functionalized with cobalt ferrites applied to the removal of bisphenol A: ionic study, reuse capacity and desorption kinetics.

A new adsorbent material based on graphene oxide (GO) functionalized with magnetic cobalt ferrite nanoparticles (γCoFe2O4) was synthesized via ultrasonication to remove the endocrine-disrupting-chemical bisphenol A (BPA) from aqueous solutions. The synthesized material (GO-γCoFe2O4) was characterized by TEM, SEM, DRX and FTIR analysis. Magnetization measures proved that the adsorbent had superparamagnetic characteristics that facilitated its separation from the aqueous solution. The maximum adsorption capacity obtained was 30 mg g-1 with adsorbent concentration of 1 g L-1, temperature of 55°C and natural pH of the solution. The experimental data were better adjusted to the kinetic models of pseudo-second-order and Langmuir isotherm. The thermodynamic parameters showed that the BPA adsorption on GO-γCoFe2O4 was spontaneous, exothermic and thermodynamically favourable. Desorption kinetics was performed using 50% ethanol as solvent, resulting in an equilibrium time of 4 h with better adjustment to the pseudo-second order kinetic model. The adsorbent showed a high regeneration capacity maintaining adsorptive capacity above 75% after 6 cycles of reuse.

Functionalized magnetite nanoparticles with Moringa oleifera with potent antibacterial action in wastewater.

Contaminations by Staphylococcus aureus in food industry environments have been extended to industrial Effluent Treatment Plant (ETP). The methodologies used in ETP for bacterial removals and quality parameters adjustment commonly use products toxic to the environment, being mostly inefficient against virulent bacteria such as S. aureus. Seeds of Moringa oleifera Lam. (MO) have potential to be used in ETP as an alternative to harmful products, as it has both the ability to regulate the physicochemical parameters of water and has antibacterial action. Functionalization of MO with magnetite magnetic nano particles (Fe3O4) at nano scale focusing on coagulation and flocculation of wastewater has been gaining prominence. Therefore, the present study evaluated the potential use of the magnetic coagulant MO-Fe3O4 in the elimination of S. aureus in synthetic dairy effluent; concomitantly sought to adjust the quality levels of physicochemical parameters. MO-Fe3O4 added to synthetic dairy effluent at different concentrations amounted to 16 treatments, which were evaluated for removal of color, turbidity, UV254nm and S. aureus on the effluent surface and sludge after 30 min of sedimentation. The results confirmed the efficient elimination of S. aureus simultaneously with a significant reduction of the physicochemical values, with constant efficiency up to 30 min. Scanning electron microscopy images confirm the removal of S. aureus on the effluent surface and sludge. Thus, this study was able to present a natural coagulant capable of remove bacteria and adjust the quality levels of the effluent after 10 min of sedimentation, making this biotechnological innovation highly applicable to ETP.