Physico-chemical and spectroscopic properties of two laterite soils for applications in arsenic water treatment
Yacouba Sanou, Clement Kolawole Balogoun, Rasmane Tiendrebeogo, Raymond Kabore, Ibrahim Tchakala, Samuel Pare
Access to safe drinking water constitutes a challenge for some rural areas in Burkina Faso where groundwater, unique source of domestic water supply, is contaminated by arsenic. Natural laterite (NL) and thermal treated laterite (TL) at 400°C were prepared and used as adsorbent for arsenic removal from enriched groundwater. The prepared adsorbents were characterized by spectroscopic techniques such as X-rays diffraction, energy dispersive spectroscopy, Fourier transform-Infrared, Brunauer-Emmett-Teller analysis, scanning electron microscopy and physical methods. Those prepared adsorbents contain aluminum oxide, quartz, hematite and goethite as mineral phases. The thermal treatment induces higher surface area of TL vs NL. Studied groundwater sample contained arsenic concentration of 122 µg/L, as well as anionic compounds such as bicarbonates, sulfates, phosphates and chlorides which can compete with arsenic removal. The treatment of arsenic water using column experiments was influenced by the flow rate of water and it became less efficient when the flow rate increased. Better treatment of arsenic (305 µg As /g for NL and 402 µg/g for TL under operational conditions) was achieved at flow rate of 8 mL/min for TL and 4.5 mL/min using NL.