Investigating groundwater resources in Egypt is crucial, particularly in light of the water scarcity issues in this hyper-arid region and the ongoing climatic challenges. The replenishment of shallow aquifers by deep mega aquifers is significant because it supports the heavily utilized and easily accessible shallow aquifers. This replenishment occurs via vertical and sub-vertical faults. In this study aeromagnetic
data were utilized to reveal subsurface deep-seated major faults and to infer their relation to major surface faults that were traced from the published geological maps of Egypt. The analysis and interpretation of the present data revealed that the main subsurface structural trend is extending NE-SW, while the main surface fault trend runs in an opposite position extending NW-SE. This discrepancy in the extension of surface and subsurface faults indicates lack of a vertical and/or subvertical continuity. Consequently, no interconnection exists between the deep Nubian Sandstone Aquifer System (NSAS) and the shallow Carbonate Aquifer System (CAS), implying no upward feeding from the NSAS towards the CAS in the study area. This anticipation is confirmed from the stable isotopic analyses for some representing groundwater samples which were carried out and published in a literature.

Aeromagnetic data was analyzed to reveal the subsurface deep-seated major faults whereas major surface faults were traced from the published geological maps of Egypt. The analysis and interpretation of these data, in combination with surface faults, revealed that the main prevailing structural trends run in an E-W, NW-SE and NE-SW directions for deep and surface faults, respectively. It was inferred that these faults are of regional aspect and extend from the deep subsurface to the shallow surface. The continuity between the deep-seated and the surface faults may forecast a possible vertical connection between the deep Nubian Sandstone Aquifer System (NSAS) and the Quaternary Aquifer System (QAS).
This suggestion is supported by previously published isotopic analyses in the region.

The ambitious agricultural development projects in Egypt and the associated horizontal expansion
into the core desert lands and desert fringe zones around the Nile Valley primarily depend on water
availability. This study investigates the vertical recharge from the deep Nubian Aquifer System (NAS)
toward the shallow aquifers, including the Carbonate and Quaternary aquifers in southern Egypt.
While this connectivity has been studied locally through case studies, the present study integrates
stable isotope data from all previous studies, together with analyses from vastly distributed new
groundwater samples, remote sensing, and geophysical methods to better understand groundwater
dynamics and aquifer connectivity over a regional domain. Findings show that: (1) the depths to the
basement surface range from 350 to 4700 m below the land surface, (2) the major structural trends
are E-W, NW–SE, NE-SW, ENE, NNW, and WNW trends, (3) the contribution ratios from the deep
NAS to the overlying aquifers range between 10 and 98% as estimated using isotope mass balance
calculations, and (4) the intersection of NW, ENE, and NE structural trends, which show similar trends
between surface faults and deep faults, indicating vertical continuity, plays a major role in aquifer
connectivity along the western desert fringes of the Nile River, particularly south of latitude 26°30′N.
These findings indicate that the relatively thin sedimentary cover overlying the NAS south of latitude
26°30′N facilitates the upwelling of the NAS groundwater along with the intersection of the NW,
ENE, and NE fault systems. Given the consensus of high hydraulic heads of the NAS compared to the
overlying aquifers, the study suggests that a large-scale vertical upwelling at the deduced intersecting
structural trends throughout the entire Limestone Plateau is worthy of further investigation. Such
vertical upwelling could bring significant groundwater resources to shallow levels, as long as the NAS
maintains its higher heads, and thus supports desert greening projects in Egypt. The findings also
highlight the necessity of examining similar mechanisms in other desert environments with multiple
aquifer systems.

Abstract:

Background: This study presents the first successful cyclic voltammetry-assisted one-step electrochemical synthesis of polyaniline-iron oxide nanocomposites. The composite films were developed by reducing an irontriethanolamine complex in an alkaline solution containing aniline monomers, enabling the uniform integration of iron oxide nanoparticles into a conductive polyaniline matrix.
Methods: The nanocomposites were synthesized through electrodeposition, and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). Thermal stability was evaluated using thermogravimetric (TGA) and differential thermal analysis (DTA).
Signifcant Findings: The synthesized nanocomposites exhibited excellent capabilities for adsorption or uptake lead and cadmium ions lead and cadmium ions from water, following a chemisorption mechanism as suggested by kinetic and isotherm modeling. The materi als demonstrated high reusability with negligible loss in adsorption effciency over three consecutive adsorption-desorption cycles, and good repeatability with consistent adsorption capacities across multiple batches. Maximum adsorption capacities reached 96.99 mg/g for cadmium and 335.57
mg/g for lead, surpassing many reported materials. This work highlights a scalable electrochemical approach for fabricating high-performance nanocomposite adsorbents for water purifcation.