Size-adsorption related studies of four Albanian natural clays toward pesticides
Date Issued
2022-10-07
Author(s)
Isak, Nensi
Xhaxhiu, Kledi
Andoni, Adelaida
Hamiti, Xhulieta
Abstract
The use of natural soil components, such as clays has recently gained increasing interest for their
promising properties as adsorbents and pesticide carriers. Four natural Albanian clays (Brari,
Currila, Dardha, Prrenjasi) were characterized by granulometric analysis and powder X-ray
diffraction. The granulometric analysis performed by Andreasen pipette and Torsion balance
techniques were employed to categorize the samples based on their particle sizes and to correlate
these parameters to their adsorption behavior toward selected pesticides. Currila and Dardha clays
reveal finer textures, consisting mostly of particles with a mean diameter of 2.6 μm. Brari and
Prrenjasi clays have a higher percentage of particles with mean diameters varying between 8 and
14 μm. Differential distribution charts show that Andreasen Pipette method reveals better
distribution results (fig. 1), especially on the determination of the largest size of particles, which are
clearly disregarded by Torsion balance method. The particle size distribution and their content
strongly influence the adsorptive capacities of these clays towards selected pesticides.
The adsorption behavior and the adsorption capacity of each clay employed were studied for
pesticide concentrations varying below their solubility limit in water. The overall adsorption process
in each case is studied by the adsorption isotherm based on Freundlich, Langmuir, Temkin and
Dubinin-Radushkevich models for a selected concentration and a variable time as well as for a
selected time against variable pesticide concentrations. Aspects of the adsorption kinetics and
intra-particle diffusion mechanisms are considered for the elucidation of the adsorption
mechanisms.
promising properties as adsorbents and pesticide carriers. Four natural Albanian clays (Brari,
Currila, Dardha, Prrenjasi) were characterized by granulometric analysis and powder X-ray
diffraction. The granulometric analysis performed by Andreasen pipette and Torsion balance
techniques were employed to categorize the samples based on their particle sizes and to correlate
these parameters to their adsorption behavior toward selected pesticides. Currila and Dardha clays
reveal finer textures, consisting mostly of particles with a mean diameter of 2.6 μm. Brari and
Prrenjasi clays have a higher percentage of particles with mean diameters varying between 8 and
14 μm. Differential distribution charts show that Andreasen Pipette method reveals better
distribution results (fig. 1), especially on the determination of the largest size of particles, which are
clearly disregarded by Torsion balance method. The particle size distribution and their content
strongly influence the adsorptive capacities of these clays towards selected pesticides.
The adsorption behavior and the adsorption capacity of each clay employed were studied for
pesticide concentrations varying below their solubility limit in water. The overall adsorption process
in each case is studied by the adsorption isotherm based on Freundlich, Langmuir, Temkin and
Dubinin-Radushkevich models for a selected concentration and a variable time as well as for a
selected time against variable pesticide concentrations. Aspects of the adsorption kinetics and
intra-particle diffusion mechanisms are considered for the elucidation of the adsorption
mechanisms.
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