Phosphorus adsorption onto green synthesized nano-bimetal ferrites: Equilibrium, kinetic and thermodynamic investigation

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2014-09, Vol.251, p.285-292
• Main Authors: Tu, Yao-Jen, You, Chen-Feng
• Format: Article
• Language: English
• Subjects: Adsorption; CuFe2O4; Ecology; Ferrites; Industrial sludge; Kinetics and thermodynamics; Maxima; Nano-bimetal ferrites; Nanostructure; Nutrients; Phosphorus
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2014.04.036

•A green technique for manufacturing CuFe2O4 was developed from industrial sludge.•The synthesized CuFe2O4 is fast and effective in removing P from polluted water.•The inner-sphere mechanism is importantly involved with P adsorption onto CuFe2O4.•The nano-CuFe2O4 can be rapidly recovered by a magnet because of its magnetism.•The results imply that 0.001 N NH4OH is sufficient for P desorption from CuFe2O4. Phosphorus (P) in natural aquatic environments is one of the most critical elements for causing eutrophication. On the other hand, it is also an essential nutrient for organisms in broad ecosystems. Therefore, it has become an important issue in environmental and ecological sciences to remove and recover efficiently of P in various water bodies. This study investigates the feasibility of P removal/recovery using nano-bimetal ferrites (CuFe2O4), manufactured from industrial sludge. These new results reveal that a rapid P removal, from 9.9% to 99.9%, was observed when the solution pH decreased from 9.06 to 2.64. The maxima P adsorption capacity was found to be 13.5mgg−1 at pH 2.64 (318K), which is much higher than other available adsorbents. The observed negative changes in the standard free energy (ΔG=−4.99, −5.47, −6.12, −7.21kJmol−1 at 288, 298, 308, and 318K, respectively) and the positive value of ΔH(1.92kJmol−1) demonstrate that the adsorption reaction is spontaneous and endothermic. Moreover, we observed also that the P adsorption increases with the increased of ionic strength from 0.001 to 1.0N, suggesting important involvement of some inner-sphere mechanisms.