The Open Catalysis Journal

2012, 5 : 31-38
Published online 2012 July 18. DOI: 10.2174/1876214X01205010031
Publisher ID: TOCATJ-5-31

River Water Discolouration with Acid Activated Kaolinite - Rich Clays

E. Djoufac Woumfo , M. Rivallan , A. H. Minkoulou , E. O. Nkot , F. Figueras and D. Njopwouo
Laboratoire de Physico- Chimie des Materiaux Mineraux, Faculte des Sciences, Universite de Yaounde 1, B.P. 812, Yaounde, Cameroun.

ABSTRACT

Nyong waters are naturally dark brown to light brown in colour because of humic substances. In the present report, Nyong waters treatment with kaolinite rich clays has been investigated. In raw state, 8 to 9 % of the best clay materials were necessary to eliminate all humic substances from Nyong waters. The best acid activation parameters were found with a mass of solution/mass of clay ratio equal to 5: 0.48 N H2SO4, 60 min activation time at 97 °C. After acid treatment, the clay content necessary for total Nyong waters discolouration was consequently reduced from 8 to 1 %. The analysis of acidic sites developed during acid activation revealed the predominance of Lewis acid sites. Very low contents (< 0.7 %) of acid-activated clay could not be employed for Nyb discolouration because of sedimentation problems. Recycling of the best acid-activated clay was based on humic substances oxidation with hydrogen peroxide in an acid medium. After 15 cycles, the acid-activated clay still discoloured Nyong waters in spite of particles erosion.

Keywords:

kaolinite, acid activation, humic substances, Nyong waters, recycling.