Fly ash superficially modified with humic substances from the Megalopolis lignitic power plant was prepared and evaluated for agricultural uses. UV-vis spectrophotometry and IR spectroscopy revealed that fly ash shows high sorption efficiency towards humic substances. Adsorption proceeds stepwise via strong Coulombic and hydrophophic forces of attraction between guest and host materials. Langmu...

The removal of tributyltin (TBT) from artificial seawater using nZnO, activated carbon and nZnO/activated carbon composite was systematically studied. The equilibrium and kinetics of adsorption were investigated in a batch adsorption system. Equilibrium adsorption data were analyzed using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) isotherm models. Pseudo first- and second-order...

Activated carbons are disorganized materials with variable pore size distributions (PSD). If one assumes that the porosity consists mainly of locally slit-shaped micropores, model isotherms can be obtained by computer simulations and used to assess the PSD on the basis of experimental isotherms. In the present study, CO isotherms have been measured at 273 K on 2 seven well-characterized micropo...

The present paper examines the adsorption of water by microporous carbons containing various amounts of surface oxygen an a smaller proportion of basic centres. The modelling of water adsorption for 293 and 310 K, using variable pore size distribution (PSD), confirms that the overall type IV isotherm is the sum of a type I isotherm associated with the specific interactions, and a typ V isotherm...

In this study, removal of copper (Cu(2+)) and zinc (Zn(2+)) from aqueous solutions is investigated using Cankiri bentonite, a natural clay. During the removal process, batch technique is used, and the effects of pH, clay amount, heavy metal concentration and agitation time on adsorption efficiency are studied. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms are applied in order to...

Potential theory on the complement of a subset of the real axis attracts a lot of attention both in function theory and applied sciences. The paper discusses one aspect of the theory-the logarithmic capacity of closed subsets of the real line. We give simple but precise upper and lower bounds for the logarithmic capacity of multiple intervals and a lower bound valid also for closed sets compris...

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...

We prove several isoperimetric inequalities for the conformal radius (or equivalently for the Poincaré density) of polygons on the hyperbolic plane. Our results include, as limit cases, the isoperimetric inequality for the conformal radius of Euclidean n-gons conjectured by G. Pólya and G. Szegö in 1951 and a similar inequality for the hyperbolic n-gons of the maximal hyperbolic area conjecture...

Feather mites of the family Avenzoariidae (Acari: Astigmata: Analgoidea) are recorded for the first time in Saudi Arabia. A new avenzoariid species, Zachvatkinia (Zachvatkinia) repressae sp. n. (Avenzoariidae: Bonnetellinae), is described from the White-cheeked Tern, Sterna repressa Hartert, 1916 (Charadriiformes: Stemidae). The new species belongs to the sternae group and is closely related to...

This study aims to determine the textural (specific surface, pore volume and size) mineralogical characteristics of Tanout red clay Zinder region (Niger) in order have data allowing its use as an adsorbent. The methodology is based on analyzes (adsorption N2 at 77 K by Brunauer-Emmett-Teller method), (X-ray fluorescence, X-ray diffraction, thermo-gravimetric analysis, scanning electron microsco...