Water defluoridation by bauxite-gypsum magnesite (B-G-Mc) based filters calcined at 350500C

International Journal of Physical Sciences

Thole B.¹ 

关键词: Defluoridation;    bauxite;    gypsum;    magnesite;    composite;    calcine;    isotherm.;   

DOI  :  10.5897/IJPS10.668

学科分类：物理（综合）

来源: Academic Journals

【 摘 要 】

Research was carried out at Ngurdoto research station in Tanzania to ascertain the potential development of a water filter made of bauxite, gypsum and magnesite in an attempt to enhance the availability of low-fluoride water. The materials were sourced within Tanzania. The X-Ray fluorescence technique showed that the major components of the materials were: bauxite: Al2O3(30.33%), SiO2(15.0%) and Fe2O3(14.3%); gypsum: CaO (28.09%), SO3(34.96%), and SiO2(9.01%); and magnesite: MgO (34.57%) and SiO2(19.3%). The materials were calcined at 350, 400, 450 and 500°C. The activated materials were then mixed in mass ratios of 1:2:3, 1:3:2, 2:1:3, 2:3:1, 3:1:2 and 3:2:1 (bauxite: gypsum: magnesite). One gram of each composite was employed in the batch defluoridation of 1 L of water with fluoride concentration of 12.62 mg/L. The highest defluoridation capacity, 11.89 mg F-/g, was obtained with the 3:2:1 to 500°C composite. The quality of the treated water fell short of WHO standards on sulphates and iron but residual concentrations of Cl-, Al3+, Ca2+, Mg2+, Fe2+were within the prescribed limits. Sorption behavior followed strongly to Langmuir isotherm, except for the 450°C calcined samples for which the Temkin isotherm behavior was pronounced. Despite the limitations of high residual sulphates and iron, a composite filter of bauxite, gypsum and magnesite was shown to be workable.

【 授权许可】

CC BY