Separation of inorganic phosphorus from municipal wastewater by solvent extraction with primary amine in the presence of sodium molybdate

Effective extraction and separation of inorganic phosphorus from municipal wastewater with primary amine as a solvent in the presence of sodium molybd ate was studied. The optimum extraction acidity was found to be at pH 6-7. When the content of inorganic phosphorus in aqueous solutions is in the ran ge of 0-300 mg L-1, the quantitative extraction of the inorganic phosphorus can be obtained with 1% primary amine in n-heptane solution and a phase ra tio of 1:1 in the presence of 10 g L-1 Mo. Over 75% organic phosphorus in w astewater cannot be extracted by primary amine. The loaded organic phase ca n be stripped quantitatively with NaOH solution and less than 20% organic p hosphorus in the organic phase can be stripped. The resultant aqueous solut ion after stripping is used directly for colorimetric determination of inor ganic phosphorus.