Phosphate removal by iron oxide-coated diatomite: Laboratory test of a new method for cleaning drainage water
Research output: Contribution to journal › Journal article › Research › peer-review
Transport of phosphate (P) in drainage water from P rich agricultural fields to freshwaters via drains may cause open water eutrophication. One way to reduce this transport is by installation of P sorbing filters at drain outlets. As drainage water flows and P concentrations can be highly fluctuating, suitable filters must have good hydraulic conductivity and high P sorbing efficiency, i.e. rapid sorption with high affinity and capacity. To fulfill these requirements, we tested a new concept for filter material design comprising porous and stable calcined diatomaceous earth particles (CDE, 2–4 mm) coated with thin layers of high affinity P sorbing amorphous iron oxide. According to NMR and MICP analyses the material had a bimodal pore size distribution with average diameters of around 1 μm and 100 μm. The coating formed a thin film on the CDE internal and external surfaces and markedly increased the P sorption efficiency. Thus, P in 0.1 and 0.5 mg P/L solutions was almost quantitatively sorbed within 1½ min at a solution:solid ratio of 100. SEM-EDX demonstrated that P quickly penetrated into the porous structure of the CDE granules and that all Fe in the coating was active in P bonding. This conceptual investigation demonstrates that porous CDE is a useful host into which Fe oxides can be precipitated resulting in an effective P sorbing material.
Original language | English |
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Journal | Chemosphere |
Volume | 222 |
Pages (from-to) | 884-890 |
Number of pages | 7 |
ISSN | 0045-6535 |
DOIs | |
Publication status | Published - 1 May 2019 |
ID: 216312579