Production and characterization of water treatment coagulant from locally sourced kaolin clays

Abstract

Base on high cost in coagulant for treating both domestic and industrial water in the recent time. There is need to identify cheaper and efficient methods of removing contaminant as the demand for clean water increases. A study was carried out to investigate the use of locally sourced Kaolinite clay from Okefomo Agbarigidoma, Ilorin south Local Government of Kwara state, for the production of aluminum sulphate using sulphuric acid (H₂SO₄) solution. The clay sample was beneficiated and calcined at 700^oC for 7 h to obtain meta-kaolin, then later leached using sulphuric acid. The effect of leaching temperature (25-100^oC),period of activation (10-120 minutes),acid concentration(1-6M),particle sizes(50-200μm),acid to clay weight ratio on the leaching were investigated. The optimum leaching conditions for the calcined Kaolin clay were found to be particle size 100μm, acid concentration 5M, leaching temperature 110^oC and leaching time of 90 min. Under optimized condition 68.75% (w/w) aluminum sulphate (alum) was extracted. The result showed that sulphuric acid could be used on a large scale to extract alum from Kaolin clay. The extract alum showed similar structure and physical characteristics compared with commercial alum. A dosage of 38mg/L of the extract alum show effective coagulant properties with a great potential of treating Industrial water.

Keywords: Clay, Calcinations, Kaolin, Sulphuric acid, Aluminum sulphate, Alum