Author: Marcos José Solache Ríos
The sorption behaviors of biosorbent based on maize (Zea mays, ZM) cane (bagasse and stalk), their composites (ZM/Fe-Cu nanoparticles) and Fe-Cu nanoparticles for malachite green from aqueous solutions were investigated in this work. Adsorbents were characterized using BET, infrared spectroscopy, X-ray diffraction, SEM-EDS, and Fe-Cu nanoparticles were characterized by TEM. The study of the sorption kinetics indicates that the adsorption on malachite green by stalk and their composite follows second-order kinetics and nanoparticles and bagasse and their composite follow the pseudo-second order model. The malachite green adsorption by ZM/Fe-Cu composites were faster than natural materials and only showed two phases in the intraparticle diffusion model, probably due to the minor internal diffusion resistance. The adsorption isotherms experimental data were analyzed by the Langmuir, Freundlich and Langmuir–Freundlich models and the equilibrium data was well described by the Langmuir–Freundlich isotherm model. The adsorption was more favorable at basic pH. The OH-groups were proportional to dye adsorption capacities. Results showed that composites (ZM/Fe-Cu nanoparticles) and Fe-Cu nanoparticles possessed good adsorption abilities to malachite green.
Project 3688/2014/CIB UAEM
Carbonaceous material obtained from the pyrolysis of sewage sludge, activated carbon (AC), a composite CM(Fe-Cu) (carbonaceous material/nanoparticles of Fe-Cu) and nanoparticles N(Fe-Cu) were used to evaluate and compare their abilities to remove phenol from aqueous solutions by adsorption followed by oxidation. The adsorbents were characterized by scanning electron microscopy, transmittance electron microscopy, Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction and Infrared (IR) spectroscopy. The presence of Fe-Cu nanoparticles was confirmed by the TEM technique. Sorption kinetics and isotherms were determined in the presence and absence of hydrogen peroxide. The experimental kinetic data of the activated carbon and the carbonaceous material were treated with Lagergren, Elovich and Ho models. The results show that both materials are best fit to the second order model indicating a chemisorption mechanism. The adsorption equilibrium of phenol by the different adsorption materials was observed in 24 h. The adsorption capacity of CM(Fe-Cu) for phenol was not affected by the pH, and the adsorption capacities for CM and AC decreased as the pH increased. The isotherms were lineal in all cases. N(Fe-Cu) was the most efficient material for the removal of phenol from aqueous solutions. The adsorption capacities decreased as the doses increased and the adsorption capacities of the materials were not affected by the temperature when it was between 30 and 50°C; only the composite CM(Fe-Cu)in the presence of hydrogen peroxide showed an endothermic behavior. The highest adsorption capacities were for N(Fe-Cu) in the presence and absence of hydrogen peroxide.
Removal behavior of indigo carmine by Schoenoplectus acutus and Ni nanoscale oxides/Schoenoplectus acutus composite was determined. The characterization of both materials was done by TEM, SEM/EDS, DRX, and BET. Experimental data were best fitted to pseudo second order and Langmuir-Freundlich models for kinetics and isotherm, respectively; these results indicate a chemisorption mechanism on heterogeneous materials. Adsorption capacity of Ni nanoscale oxides/Schoenoplectus acutus composite was high in comparison with other adsorbents (760 mg/g). Adsorption of dye is not affected by pH (3 to 9). Metal nanoparticles supported on cheap and eco-friendly adsorbents are an alternative for the removal of dyes from wastewater.
Carbonaceous material obtained from industrial sewage sludge and Na-zeolitic tuff were used to adsorb cadmium from aqueous solutions in column systems. The Bohart, Thomas, Yoon–Nelson, and mass transfer models were successfully used to fit the adsorption data at different depths, and the constant rates were evaluated. The parameters such as breakthrough and saturation times, bed volumes, kinetic constants, adsorption capacities, and adsorbent usage rates (AUR) were determined. The results show that the breakthrough time increases proportionally with increasing bed height. The adsorption capacity for cadmium for Na-zeolitic tuff was higher than carbonaceous material. The results indicated that the Na-zeolitic tuff is a good adsorbent for cadmium removal.
CONACYT, project 131174Q, and PROMEP/103.5/13/6535 project.