Keywords: Metal-organic frameworks; Water purification; Phosphorus recovery; UiO-66
Excessive discharge of phosphorus (P) to natural watercourses not only causes eutrophication of water bodies but also results in the loss of P resources. P-containing wastewater is a crucial secondary P resource. Zirconium-based metal-organic frameworks (MOFs), particularly UiO-66 has been shown great promise in efficiently capturing P from water. In this study, a group of UiO-66@sponge composites was prepared by a facile layer-by-layer in-situ growth approach using melamine sponge (MS) as scaffolds. The as-prepared UiO-66@sponge composites exhibit high chemical and dimensional stability when used as adsorbents for reclaiming P from wastewater. Batch adsorption results show that one UiO-66@sponge composite exhibited the highest phosphorus adsorption capacity of 83.55 mg g−1 at pH 6.0, outperforming most other UiO-66 adsorbents under environmentally relevant conditions. The intrinsic mechanical flexibility and chemical stability of these UiO-66@sponge composites enable us to efficiently enrich phosphorus from a dilute solution by a rapid adsorption-desorption operation. This work provides a promising strategy to integrate MOFs with dimensionally stable and flexible sponges for rapid adsorption and recovery of phosphate from wastewater and could be potentially expanded to the recovery of other value-added or technology-critical elements from waste streams.
