The physicochemical and structural characteristics of Cu2+ contaminated undisturbed loess
The effects of Cu2+on the physicochemical and structural characteristics of undisturbed loess were studied in order to formulate effective strategies for environmental protection,soil pollution prevention and re-mediation,and to provide theoretical support for the engineering construction of contaminated sites.The parti-cle size distribution,CaCO3 content and pH value of Cu2+contaminated loess samples were determined.The SEM images and particle size contents of the samples were obtained by scanning electron microscopy and laser particle size analyzer.The influence mechanism of Cu2+on the microstructure of undisturbed loess was ana-lyzed by means of fractal theory.The compression test of Cu2+contaminated undisturbed loess was carried out,and the comprehensive structural potential of the sample was analyzed.The results show that with the increase of Cu2+content,the clay content increases first and then decreases,and then increases and then decreases,while the powder content decreases first and then increases,and the sand content remains unchanged.The content of CaCO3 decreased linearly.The pH value decreases rapidly at first,and then remains unchanged.The comprehensive structural potential of the contaminated loess samples first increased and then decreased,and then increased and then decreased.In general,the incorporation of heavy metal Cu2+leads to the de-crease of soil pH value,the dissolution of the main cementing material calcium carbonate,and the change of the form and composition of clay aggregates due to the electrostatic attraction and van der Waals forces between clay particles,thus affecting the compactness and structural strength of soil.
Cu2+undisturbed loessSEM imagescomprehensive structural potentialparticle size distribu-tionfractal theory
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