This study compared the abilities of two low-cost materials: a dried activated sludge and sunflower leaves to remove cadmium from aqueous solutions. Kinetic data and equilibrium sorption isotherms were measured in batch conditions. Kinetics of cadmium sorption was time contact and initial cadmium concentration dependent. The cadmium uptake of these two low-cost materials was quantitatively eval...

Thermodynamic studies on the bioadsorption of Cr(III) onto Agave lechuguilla biomass were conduced. The experimental results at different temperatures were modeled using the Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model. Both the Freundlich and Langmuir models were found to represent the bioadsorption process. The average adsorption capacities calculate...

A commercial multiwall carbon nanotube and its carboxylated derivate (CNTC and COOHC, respectively) was used after purification to study the competitive adsorption of phenol (P) and m-chlorophenol (CP) from 0.1 M aqueous NaCl solutions without external pH control. The adsorption takes place practically exclusively on the external surface of the nanotubes. The uptake of P is suppressed in compar...

We develop a model for solute transport in porous media, which takes into account equilibrium and non-equilibrium multiple-site adsorption. Binary ion exchange is included. Adsorption rate formulations and their isotherms are reviewed and their mathematical properties investigated. This forms the basis of the study of travelling wave solutions in the second part of the paper.

The sorption of three basic dyes, named basic violet 10, basic violet 1, and basic green 4, from aqueous solutions onto sugarcane dust was studied. The results revealed the potential of sugarcane dust, a waste material, to be a low-cost sorbent. Equilibrium isotherms were analyzed using the Langmuir, the Freundlich, and the three-parameter Redlich-Peterson isotherms. In order to determine the b...

One of the causes of water pollution is the presence of heavy metals in water. In the present study, an adsorbent prepared from the raw bark of the Pongamia pinnata tree is used for the removal of ferrous or ferric ions from aqueous and waste water containing heavy metals. Adsorption studies were conducted at different pH, concentration of metal ion, amount of adsorbent, contact time, agitation...

The main aim of the paper is to evaluate ferroprecipitates as immobilization agents for removing selected surfactants from aqueous solutions. Two ferro-precipitates based on iron oxides were used. Adsorbents were varied both in elementary composition and mineral composition. Sodium dodecyl sulphate (SDS) was used as a model anionic surfactant. Simultaneous measurements of the surfactant’s adsor...

Control of the regulatory enzyme threonine deaminase from Escherichia coli is achieved by isoleucine inhibition and valine activation. The mechanism by which these heterotropic effectors regulate the enzyme was investigated by measuring the binding of isoleucine and valine by spectroscopic, kinetic, calorimetric and equilibrium dialysis techniques. The addition of isoleucine or valine to threon...

We have used amperometric measurements in a model system consisting of two liposomes connected with a membrane nanotube to monitor catechol release during artificial exocytosis and thereby to elucidate the effect of small-chain alcohols on this dynamic membrane process. To determine the rate of membrane shape change, catechol release during membrane distention was monitored amperometrically, an...