No abstract

A thermodynamic and kinetic study of the adsorption process of Zn (II) and Pb (II) ions from aqueous solution on the surface of graphene oxide (GO) to establish the mechanisms of adsorbate–adsorbent interaction on this surface. The effect of pH on the retention capacity was studied and adsorption isotherms were determined from aqueous solution of the ions; once the experimental data was obtained, the kinetic and thermodynamic study of the sorption process was carried out. The data were fitted to the Langmuir, Freundlich, Dubinin-Raduskevich and Temkin isotherm models. The results showed that Zn(II) and Pb(II) on the GO adsorbing surface fitted the Langmuir model with correlation coefficients (R2) of 0.996. Kinetic models studied showed that a pseudo-second-order model was followed and thermodynamically, the process was spontaneous according to the values of Gibbs free energy (ΔGo). N2 adsorption isotherms were determined and modeled with the NLDFT (nonlocal density functional theory) and QSDFT (quenched solid density functional theory) kernels.

No abstract

No abstract

No abstract

This is the first study to carry out a laboratory-scale assay to assess the potentiality of continuous liquid-liquid extraction with dichloromethane (CLLE DCM ) and high-power fractional distillation (HPFD) as a treatment to decontaminate the wastewater generated by the petroleum industry (WW). The analytical parameters of treated wastewater (TWW) evidenced a remarkable quality improvement compared to the original WW. CLLE DCM -HPFD yielded 92.4%-98.5% of the WW mass as more environmentally friendly water. Compared to the original values determined in the WW, total petroleum hydrocarbon (TPH) decreased by 95.0%-100.0%, and the chemical oxygen demand (COD) decreased by 90.5%-99.9%. Taking into account the yield of the treated water, the amount of pollutant removed, and the risks of each process, the order of the potentiality of these treatments, from highest to lowest, was HPFD > CLLE DCM -HPFD > CLLE DCM . CLLE DCM treatment alone produced TWW with poorer quality, and the CLLE DCM -HPFD sequence involved the greatest consumption of time and energy (0.390-0.905 kWh/kg). CLLE DCM -only was the least effective treatment because the TWW obtained failed to comply with the regulations of oil-producing countries.

In this work, the textural parameters of graphene oxide (GO) and graphite (Gr) samples were determined. The non-local density functional theory (NLDFT) and quenched solid density functional theory (QSDFT) kernels were used to evaluate the pore size distribution (PSD) by modeling the pores as slit, cylinder and slit-cylinder. The PSD results were compared with the immersion enthalpies obtained using molecules with different kinetic diameter (between 0.272 nm and 1.50 nm). Determination of immersion enthalpy showed to track PSD for GO and graphite (Gr), which was used as a comparison solid. Additionally, the functional groups of Gr and GO were determined by the Boehm method. Donor number (DN) Gutmann was used as criteria to establish the relationship between the immersion enthalpy and the parameter of the probe molecules. It was found that according to the Gutmann DN the immersion enthalpy presented different values that were a function of the chemical groups of the materials. Finally, the experimental and modeling results were critically discussed.

No abstract