Apatite as an interesting seed to remove phosphorus from wastewater in constructed wetlands

Abstract

Intensive use of phosphates has resulted in high P levels in surface waters and therefore eutrophication problems. Over the last decade many studies have revealed the advantage of using specific materials with efficient phosphorus retention capacities. Recent studies state that Ca materials are of particular interest for long-term retention of P, but can induce negative effects. To improve P retention and avoid negative counter-effects we tested the potential of natural apatites. Apatite sorption was evaluated using batch and open reactor experiments. Batch experiments identify sorption mechanisms and the influence of the ionic characteristics of the solution; open reactor experiments evaluate sorption capacities in relation to the ionic composition of the solution and biomass development. In parallel, observation of the material by electron microscopy was used to give more precision information about the mechanisms involved. This work reveals the strong chemical affinity between apatites and phosphorus. Compared to other calcareous materials apatite is better able to maintain low outlet P levels. After more than 550 days feeding, sorption was still present and low P outlet levels were still being obtained when sufficient contact time and calcium content in the solution were ensured. This work demonstrates the advantages of using apatites for phosphorus removal in constructed wetlands. The behaviour of apatite in phosphorus retention is explained and its suitability for use in such extensive systems defined.

Thermal treatment effect on structural features of mechano-synthesized fluorapatite-titania nanocomposite: A comparative study

“…The close chemical similarity of HAp to natural bone has led to the extensive research efforts to use synthetic HAp (s-HAp) as a bone substitute and/or replacement in biomedical applications [3]. Besides, HAp and its modified structures have been investigated for drug delivery [4], gene therapy [5],  chromatography [6] and waste water remediation [7]. Over the past, nanostructured materials become very common in biomedical applications [8,9].…”

Evaluación De Un Sistema De Tratamiento Doméstico Para Reúso De Agua Residual

“…Al respecto, ha sido reportado que en los HC, para obtener una remoción continua de fósforo es muy importante conocer la capacidad de adsorción del ME (Brix et al 2001) y su potencial de saturación (Drizo et al 2002), además de la capacidad de este ME para precipitar el fósforo (Arias y Brix 2005). Por esta razón, recientemente se han estudiado diferentes materiales: grava (Molle et al 2005), apatita (Bellier et al 2006), conchas de ostras (Seo et al 2005) y cenizas y escoria de metal (Xu et al 2006). Por otra parte, Korkuzus et al (2005) reportan que en HC empacados con grava, como es el caso de este estudio, los principales mecanismos de remoción de fósforo son la adsorción y las reacciones de precipitación con Ca, Al, y Fe pero también la asimilación.…”

Comparison between Ti‐ and Si‐based mesostructures for the removal of phosphorous from aqueous solution

“…Also, titanium has been proposed to as a novel, more selective chemo-affinity sorbent candidate. Marie-Luise et al [32] indicated that inorganic phosphate strongly binds and replaces all other ligands on titanium centers. Conversely, despite the silica mesostructure having a huge surface area, its adsorption capacity was small due to the low affinity for phosphorous.…”