Feasibility of Adsorption Kinetic Models to Study Carrier-Mediated Transport of Heavy Metal Ions in Emulsion Liquid Membranes

Emulsion liquid membranes have been successfully used for the removal of different types of organic and inorganic pollutants by means of carrier-mediated transport mechanisms. However, the models that describe the kinetics and transport of such mechanisms are very complex due to the high number of model parameters. Starting from an analysis of the similarity between the elemental mechanisms of carrier-mediated transport in liquid membranes and of transport in adsorption processes, this paper presents an experimental analysis of the possibility of applying kinetic and mechanistic models developed for adsorption to carrier-mediated transport in emulsion liquid membranes. We study the removal of a target species, in this case, Cu(II), by emulsion liquid membranes containing membrane phase solutions of benzoylacetone (carrier agent), Span 80 (emulsifying agent) and kerosene (diluent), and hydrochloric acid as a stripping agent in the product phase. The experimental results fit the pseudo-second-order adsorption kinetic model, showing good relationships between the experimental and model parameters. Although both Cu(II) diffusion through the feed/membrane interface boundary layer and complex Cu-benzoylacetone diffusion through the membrane phase controls Cu(II) transport, it is the former step that mainly controls the transport process.

Tetracycline Removal from Water by Adsorption on Geomaterial, Activated Carbon and Clay Adsorbents

The use of antibiotics for breeding and for humans increased considerably in recent years, as a dietary supplement to enhance animal growth. This frequent use leads to the detection of residues in water and wastewater. Thus, the emergence of new strains of bacteria resistant to these antibiotics and, can lead to incurable diseases of livestock, and can lead to a possible transmission of these strains to humans. The purpose of this work is to develop new materials based on treated Maghnia clay, activated carbon, cement, and PVA polymer, named geomaterials. These materials were intended for the containment of hazardous wastes in landfills. The removal of tetracycline from aqueous solution was tested by adsorption onto synthesised geomaterials and their mineral constituents. Adsorption kinetics revealed that tetracycline was rapidly retained by GM and ATMa. This was confirmed by the relatively short equilibrium time of 30 min. The pseudo-second-order and intraparticle models well fitted the adsorption kinetic of the TC-adsorbent studied systems. It was noticed that the adsorption kinetic passes through several mechanisms, was demonstrated by the multi-linearity on the plot of qt against the square root of t. The adsorption capacity (Qa ) of TC onto GM is pH-dependent. Indeed, Qa reaches a maximum value (Qa = 12.58 mg ∙ g–1 at a very acidic pH of 2, then the adsorbed amount decreases to reach a minimum value at pH of 8, and for basic pHsQa increases up to 10 mg ∙ g–1.

Comparative between different Natural Sources of Activated Carbon for the Removal Reactive Green Dye from Aqueous Solution

Water pollution is one of the biggest problems facing us, so it requires the need to develop a very high-efficiency and inexpensive absorbent material from natural surfaces and compare it with expensive commercial sorbents. Where in this study an absorbent substance was prepared from the natural surfaces of Syzgium Aromaticum Flower Bud (SAFB), Nigella Sativa (NS) Converted to activated carbon to activated carbon Activated (SAFB), and Activated (NS), as these surfaces are characterized by high porosity, cheap price and very high efficiency in removing dye. The composite was illustrated via different analysis apparatus included FTIR, and FE-SEM, The adsorption result were fitted with Freundlich isotherms. The experimental kinetic result at different primary reactive green dye concentrations, were also analyzed through first model, second model and Elovich model. The obtained data appear that the model pseudo-first model fits the adsorption kinetic result through R2 0.96028, R2 0.9486, R2 0.9016 and R2 0.9620 of SAFB and ACTIVE-SAFB and Nigella Sativa (NS) and Activated (NS) in the same order.

Study Into Dynamic Behaviour of the Methylene Blue Adsorption on Activated Carbon

This paper presents a study into dynamic behaviour of the methylene blue adsorption (MB) on activated carbon. Effect of four parameters were studied: effect of the adsorbent dosage, effect of contact time, effect of pH, and effect of the initial concentration of methylene blue. The adsorption kinetic data were modelled using the pseudo-first and pseudo-second orders. Results show that, based on the experimental data, the pseudo-second order could be considered satisfactory. Thermodynamic parameters proved that adsorption of dye was spontaneous owing to increase in temperature and endothermic nature. Taguchi method was applied to determine the optimum conditions for removal of methylene blue by activated carbon. The optimum conditions were found to be pH = 7, contact time 60 min, initial concentration of MB 4 mg/L.