The seepage transport of heavy metal Pb²⁺ through sand column in the presence of silicon powders

Abstract

The coupled transport of heavy metals with suspended particles has been a topic of growing interest. The main purpose of this study is to experimentally investigate the seepage transport of heavy metal Pb2+ in the presence of silicon powders (SPs) through a sand column under different seepage velocities (v = 0.087–0.260 cm/s), injection Pb2+ concentrations (CP = 0–800 μg/ml) and SP sizes (D50 = 2.8–25.5 μm), which were likely to be encountered in practical engineering. The sand column was installed in a cylindrical chamber of 300 mm in length and 80 mm in internal diameter. The results clearly show that the increase in acidity results in a reduction of the repulsive interactions between SPs and the matrix, and consequently a decrease in the peak values in breakthrough curves (BTCs), especially for larger-sized SPs. The peak values and recovery rate of Pb2+ are obviously increased and an earlier breakthrough can be observed, due to the higher capacity of SPs with negative charge to adsorb heavy metal pollutants such as Pb2+ with positive charge. The adsorption of Pb2+ on SPs can reduce the repulsive forces between SPs and the matrix, thus resulting in the increase of the deposition possibility of SPs and the decrease of peak value and recovery rate.

Hydrobiochemical balance of total mercury in a forest catchment area at former cinnabar mining locality

“…The topic of adequate modeling of the groundwater contamination by various substances, including heavy metals such as cadmium, mercury and lead has become one of the most important tasks for soil hydrologists in the last decade. The transport of solutes in soils, and its intensification due to the preferential flow (especially macropore flow), plays crucial role when problems related to the groundwater pollution are dealt with (Bai et al, 2019;Navrátil et al, 2015;Vogel et al, 2007).…”

The Promotion/Inhibition of the Seepage Transport of Copper Ions by Suspension-Colloidal Particles with Wide Size Gradation

“…In fact, the factors affecting the coupled transport of suspended particles and heavy metal ions not only include the concentration of suspended particles, particle size [24,25], seepage velocity [26,27], temperature [28,29], gravity effect [30,31], and type and pH of heavy metal ions [32] but also include a variety of factors such as the type of porous media and physicochemical properties [33]. In this regard, many laboratory experiments have been accomplished to establish models for the deposition and release of suspended matters [34] as well as to establish the governing equations for the cotransport of multiple components [35][36][37]. Chrysikopoulos and Katzourakis [38] demonstrated that the dispersivity of colloids is not only a function of colloid size but also a function of seepage velocity by laboratory and field studies.…”