2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 5
Presentation Time: 9:10 AM

Effects of Zeolite Amendment on Soil Phosphorus

LI, Yuncong, Soil and Water Science, University of Florida, 18905 SW 280 Street, Homestead, FL 33031, WANG, Xing, Miami, 33033 and NKEDI-KIZZA, Peter, Soil and Water Science, University of Florida, Gainesville, FL 32611, Yunli@ufl.edu

The study consisted of two experiments: 1) phosphorus (P) sorption on zeolite using a batch method; and 2) Zeolite was amended in columns containing one of three south Florida soils. Phosphorus sorption on zeolite was described with Langmuir isotherm equations. The P sorption maximum ranged from 29 to 82 mg P kg-1, slight higher than the sandy soil of study. The Langmuir sorption energy for zeolite products ranged from 0.40 to 2.97. Zeolite sorption for P can be manipulated by different treatment to its external surface property. Three times washing with 1N HCl caused an 81.7% decrease in sorption maximum on ZEO1 zeolite. In contrast, the formation of a HDTMA bi-layer membrane around ZEO1 increased its sorption maximum by more than three fold while the sorption maximum for iron-oxide coated ZEO1 was 123.4 times of that for uncoated ZEO1. Phosphorus sorption by zeolite was an initial rapid process, followed by a slow sorption stage that persisted over time. About 87.4% of P sorption on ZEO1 was completed within the first 312 hr. The reaction was best described by a Langmuir kinetic model (r2 = 0.998). P sorption on ZEO1 was a pH dependent reaction and maximum P sorption peaked at pH 5 to 7.