The Effect of Sol-Gel Coatings on the Phosphorus (P) Adsorption Capacity of Calcareous Materials for Use in Water Treatment

Solvei Mundbjerg Jensen,Helmer Søhoel,Carlos A Arias,Frances Helen Blaikie,Hans Brix

doi:10.3390/w14010003

Solvei Mundbjerg Jensen, Helmer Søhoel + Show 3 more

Open Access

https://doi.org/10.3390/w14010003

Copy DOI

Journal: Water	Publication Date: Dec 21, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: Danish Technological Institute, Aarhus University, AgResearch

Abstract

(1) Phosphorus (P) removal has proven difficult in decentralized wastewater treatment systems, and P binding material, installed as an external filter, has been proposed for improving P removal. Especially, calcium (Ca)-rich materials have shown promising results. (2) Five calcareous materials were tested with isotherm batch experiments. The material with the highest P adsorption capacity was selected to undergo different Sol-Gel coatings, i.e., different coating dilution ratios (1:10, 1:5, and 1:1) and exposure periods (5, 10, and 15 min). The seven coated materials were evaluated by isotherm experiments. (3) The maximum adsorption capacity (Qmax) was determined by fitting the Langmuir equation. Qmax for the non-coated materials, and ranged from 0.7 (sand) to 35.1 (Catsan) mg P g−1 DW, while the coated materials ranged from 7.8 to 24.7 mg P g−1 DW depending on the coating. Based on the rotated Principal Component Analysis, the most important parameters for Qmax were the texture and the Ca content. (4) Catsan was the most promising material, but when performing a Sol-Gel coating, a trade-off between preserving Qmax and the coating thickness were evident, as the materials with the thinner coating preserved more of the sorption capacity. The development of P binding materials constitutes a useful technology in decentralized wastewater treatment systems.

Highlights

Aarhus University Centre for Water Technology (WATEC), Department of Biology, Aarhus University, Ny Munkegade 120, 8000 Aarhus, Denmark
Qmax for the non-coated materials, and ranged from 0.7 to 35.1 (Catsan) mg P g−1 dry weight (DW), while the coated materials ranged from 7.8 to 24.7 mg P g−1 DW depending on the coating
(4) Catsan was the most promising material, but when performing a Sol-Gel coating, a trade-off between preserving Qmax and the coating thickness were evident, as the materials with the thinner coating preserved more of the sorption capacity

Summary

Introduction

Abstract: (1) Phosphorus (P) removal has proven difficult in decentralized wastewater treatment systems, and P binding material, installed as an external filter, has been proposed for improving P removal. The seven coated materials were evaluated by isotherm experiments. Qmax for the non-coated materials, and ranged from 0.7 (sand) to 35.1 (Catsan) mg P g−1 DW, while the coated materials ranged from 7.8 to 24.7 mg P g−1 DW depending on the coating. (4) Catsan was the most promising material, but when performing a Sol-Gel coating, a trade-off between preserving Qmax and the coating thickness were evident, as the materials with the thinner coating preserved more of the sorption capacity. The development of P binding materials constitutes a useful technology in decentralized wastewater treatment systems. The majority of P fertilizers are obtained from phosphate rock reserves, but these reserves have been estimated to become depleted in the future [5,6]

Objectives

Methods

Results

Conclusion