Abstract
Eutrophication has been a serious environmental problem all over the world. Nutrients such as nitrogen and phosphorus discharged into enclosed water bodies are major factors in eutrophication. The purpose of this study is to characterize the removal of ammonium and phosphate from food industrial wastewater with aluminosilicate. In batch experiments, adsorption kinetics of NH_4^+-N were described by the pseudo second order kinetic model. The adsorption isotherm for NH_4^+-N fit the Langmuir plots with 8.21mg-N g^<-1> adsorption maximum and Henry plots was suitable for PO_4 adsorption. The NH_4^+-N adsorption onto aluminosilicate was ion exchange reaction between Na^+ and NH_4^+. The removal percentage of NH_4^+-N from 50 mL of 5 mg-N L^<-1> standard solution was greater than 85% at the initial pH 4-10. The NH_4^+-N removal decreased in the presence of the competitive ions and interference with competitive ions followed in the order of Ca^<2+> > Mg^<2+> > K^+ > Na^+. The removal percentage of PO_4 from 50mL of 5mg-PO_4 L^<-1> standard solution was highest at pH 3.7 and low values at pH < 1.5 and 5.6 <. However, the removal percentage of PO_4 from 50mL of 5mg-PO_4 L^<-1> mixed solution contained Ca^<2+>, Mg^<2+>, NH_4^+ was 28.4% and the PO_4 in food industrial wastewater was removed well even if the pH value was 5.9-8.0, which removal mechanism still remains to be solved. The removal percentages of NH_4^+-N and PO_4 from food industrial wastewater were 20.6-74.3% and 73.5-80.0%, respectively.
