62 Advancing the Understanding and Management of Groundwater Pollution with Arsenic and Other Geogenic Contaminants Using Geospatial Tools, Machine Learning, and Data Science (Posters)

The growing trend of data aggregation and analysis, along with emerging technologies like machine learning, has significantly improved our understanding of groundwater basins, enabling better assessments of water quality for direct consumption and treatment in groundwater supply management.

Sunday, 19 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Study of Removal of Contaminants from Water Using Raw and Modified Bauxite from Northern Mississippi

Paper number: 62-1
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Exposure to contaminants; Fluoride-arsenic rich drinking water leads to serious health risks globally. Bauxite, an abundant and low-cost clay-rich sedimentary rock, shows potential removal of contaminants from drinking water sources. This study uses untreated and treated bauxite collected from the Randolph Road Metal Pit, Pontotoc County, Mississippi, to examine the removal of fluoride and arsenic. Bauxite samples were classified as clay-rich or iron-rich and modified by acidification with 0.5 M hydrochloric acid (followed by neutralization), Calcination at 600 °C for four hours, and a combined form of both acidification and calcination.

Arsenic experiments were conducted using a solution with an arsenic concentration of 69.1 ppb and a dosage of 1 g/L of bauxite powder, with a 24-hour contact time. A total of 25 samples were analyzed, including raw, acidified, calcinated, and combined versions of clay-rich and iron-rich bauxites. All types of Bauxites show >90% removal of arsenic, while acid-treated iron-rich bauxite achieves the highest efficiency of As removal (96%), and untreated samples exceeded 94%, highlighting the strong natural adsorption capacity. Fluoride removal experiments used 10 g/L dosages across 4–12 ppm concentrations of fluoride at 3–48 hour contact times. Raw bauxite shows lower efficiency while modified bauxite shows a significantly higher removal. Acidified clay-rich bauxite removed 69% of 4 ppm fluoride, after 48 hour contact time. Removal of fluoride improved with longer contact times but declined at higher initial fluoride levels, dropping to 35% at 12 ppm, as the availability of adsorption sites serves as the limiting factor. Additional trials confirmed a positive correlation between sorbent quantity and fluoride removal, increasing from 3% at 1 g/L to 44% at 10 g/L.

The high arsenic removal efficiency observed in raw bauxite highlights its natural affinity for arsenic, due to the presence of iron and aluminum oxides. Acid treatment enhances this performance by increasing surface reactivity and exposing more adsorption sites. Fluoride removal improves with treated bauxite and extended contact times, suggesting enhanced porosity and increased interaction of sorbent and contaminant. Higher initial fluoride concentrations reduce removal efficiency, indicating that active sites are saturated and reflecting the relationship between adsorption capacity and contaminant load.

These preliminary results suggest that both raw and treated bauxite from northern Mississippi could potentially serve as effective, low-cost material for removing contaminants from groundwater.

 

 

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-413255

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