Bauxite : a prospective mineral for arsenic elicitation from water and acidity influence

• The study evaluates the performance of bauxite for arsenic (As) elucidation from water. The raw, calcined, and alkaline ferric-bauxite composite was applied in batch experiments to evaluate the influence of dosage, initial As concentrations, contact time, and pH. The X-ray diffraction studies revealed significant content of gibbsite (Al(OH)3 in the bauxite. Visual MINTEQ simulation indicated As removal increases with an increase in dosage, the pH range between acidic and near neutral favors maximum removal. The 100 g/L calcined bauxite at pH 7.4 removed 99.9% As to below 0.001 mg/L after 20 minutes from an initial concentration of 1 mg/L. The raw 100 g/L bauxite at pH 6 removed 99.86% As to below 0.003 mg/L after 1 hour from an initial As concentration of 1 mg/L. The alkaline ferric-bauxite composite used for treatment of 2 mg/L As raised pH from pH 4 to 12, and removal efficiency declined to 31% after 4 hours. Aluminium (Al) was sensitive to pH, and about 435 mg/L was released in water at pH 12. Despite the decrease in specific surface area during calcination at 500 °C, the As removal was more improved for the calcined bauxite. The removal capacity was high, up to 6 mg/g, when less dosage of 0.5 g/L bauxite was used. The kinetic reaction process using 5 g/L reaction obeys pseudo-secondorder with R2 of 0.99 while its removal isotherm obeys Langmuir with R2 of 0.98 and is confirmed favorable.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Nyckelord

Arsenic

Bauxite

Dosage

pH

Drinking water

Adsorption

Tanzania

Mark- och vattenteknik

Land and Water Resources Engineering

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)