Effect of pH on phosphorus (P) dissolution and recovery from polyaluminum chlorides (PAC) sludge.
Phosphorus (P) dissolution from polyaluminum chlorides (PAC) sludge was investigated for sustainable P recovery. P dissolution followed 1st order kinetics with the rate constants of 3.8 × 10-2, 0.8 × 10-2, 1.3 × 10-2 and 1.9 × 10-2 min-1 at pH 1, 2.5, 10.5 and 12, respectively. Strong acidic and alkaline conditions dissolved about 82 (pH 1) and 88% (pH 12) of the total P by adding 0.214 g HCl and 0.357 g NaOH per gram P dissolved, respectively. Chemical P fractionation showed that more than 96% of the total P of the PAC sludge was AlP and it was reduced to 11.3 (pH 12) and 12.6% (pH 1.0) after the acid and alkali treatment. ATR-FTIR showed that AlPO4 in the PAC sludge was transformed to Mg3(PO4)2∙4H2O and CaHPO4∙2H2O after alkali treatment and H3PO4 and Na/MgP after acid treatment. Dissolved P can be recovered by precipitation with Ca and Mg.
['Toor|Umair Ali|UA|', 'Kim|Dong-Jin|DJ|']
D000536:Aluminum Hydroxide D006863:Hydrogen-Ion Concentration D010758:Phosphorus D012722:Sewage D012995:Solubility
pH Polyaluminum chlorides ATR-FTIR Dissolution kinetics Phosphorus dissolution Phosphorus fractionation