Phosphate Adsorption onto an Al-Ti Bimetal Oxide Composite in Neutral Aqueous Solution: Performance and Thermodynamics

Phosphorus (P) pollution and phosphorus recovery are important issues in the field of environmental science. In this work, a novel Al-Ti bimetal composite sorbent was developed via a cost-effective co-precipitation approach for P removal from water. The adsorptive performance and characteristics of P onto Al-Ti sorbent were evaluated by batch adsorption experiments. The effects of Al:Ti molar ratio, initial P concentration and reaction temperature were investigated. The microstructural characteristics of the Al-Ti sorbent were confirmed by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, and nitrogen adsorption-desorption measurements. Kinetic studies showed that the adsorption of P on Al-Ti oxide proceeds according to pseudo-second-order kinetics. The maximum adsorption capacity of phosphate on the Al-Ti oxide calculated from linear Langmuir models was 68.2 mg-P/g at pH 6.8. The Al-Ti oxide composite sorbent showed good potential for P recovery, owing to its large adsorption capacity and ease of regeneration.