Combined natural and chemical coagulants to remove fluoride from wastewater

Abstract

The combined chemical and natural coagulant showed greater fluoride ion removal in synthetic hydrofluoric acid wastewater when compared to natural coagulant or chemical coagulant treatment alone. The impact of applying fibrous thin film on the coagulation activity was assessed in this study. In this study, a new chemical coagulant called Ecogent F-Loc was introduced. It can increase 40% of fluoride removal when combined with sodium aluminate. Combined chemical and natural coagulants gave the highest fluoride reduction using the Moringa Oleifera seed and eggshell with dosage of 100 ppm were 57% and 73%, respectively. When the chemical coagulant added with Moringa Oleifera seed, the fluoride removal efficiency increased from 50% to 77%. This showed that the combined chemical and natural coagulant showed similar coagulation effect as conventional chemical coagulant. In term of fibrous thin film, there is no significant effect on the coagulation activity of coagulant, but it helped to reduce the turbidity and coagulant residue in the synthetic wastewater and used to produce ionic solution for fluoride removal. In addition, the direct contact between particles and the impeller of Jar Test equipment can destroy the surface morphology of coagulant particles. With the support of the fibrous thin film, this challenge can be solved. In conclusion, the combined natural and chemical coagulant solutions can be used to substitute existing chemical treatment in fluoride wastewater treatment.