Beyond the boundaries of phosphate desorption
Uncovering the surface chemistry behind phosphate-iron (hydr)oxide sorption
Research conducted at Wetsus has demonstrated that continuous adsorption with iron (hydr)oxide-based adsorbents can reliably remove phosphate from wastewater treatment plant effluents to ultra-low concentrations.
Regeneration is essential to ensure an efficient reuse of the adsorbent, yet this remains a critical step. Regeneration relies on concentrated alkaline solutions to exchange adsorbed phosphate, yet a significant fraction of the regenerant is consumed in other competing processes, both at the adsorbent-solution interface and within the material structure.
A better understanding of the surface chemistry and physicochemical mechanisms governing regeneration is therefore needed. Unravelling these mechanisms will provide fundamental insight into the interactions between phosphate, the adsorbent, and the regenerant, and help establish the scientific basis for more efficient regeneration.
Research challenges
Most regenerant consumption is attributed to competing processes, but the underlying mechanisms remain poorly understood. In addition, phosphate adsorption appears to involve only a fraction of the surface of iron (hydr)oxide-based adsorbents, while the entire surface interacts with the regenerant, further impacting regeneration efficiency.
Conflicting results on desorption mechanisms, efficiency, and kinetics have been reported in the literature. This highlights the need to better understand the factors influencing regenerant demand by investigating the mechanisms governing the interaction between the regenerant, the adsorbent surface and porous structure, and different co-adsorbed compounds (e.g., organic matter).
Finally, the pH neutralization required after regeneration involves additional effort and chemical consumption. Addressing these challenges is essential to improve the overall efficiency and economic viability of the technology.
Your assignment
You will explore the interface between material science, physical chemistry, chemical engineering, and environmental science. You will investigate the fundamental mechanisms governing the surface chemistry of phosphate adsorption and desorption on iron (hydr)oxides.
You will use your creativity and outside-the-box thinking to design innovative experiments and develop effective nanostructured adsorbents to address these fundamental questions.
You will use advanced analytical techniques to unravel the complex surface processes governing sorption. You will get acquainted with liquid-phase analytical techniques such as IC, ICP-OES, TOC, and material characterization techniques, such as Mössbauer spectroscopy, SEM-EDX, TEM, FTIR, XRD.
Through the Wetsus framework, you will also benefit from the expertise and knowledge of the involved industrial partners within the Phosphate Recovery Theme.
This ambitious project promises to be highly varied and interdisciplinary, within an international environment.
Your profile
We are looking for a master graduate with a background in either material science, chemistry, chemical engineering or related fields. You need to be able to bridge theoretical knowledge like surface chemistry to concrete process engineering concepts.
Keywords: Material Science; Surface Chemistry; Resource Recovery; Water Technologies; Advanced Characterization
Professor/University group/Wetsus supervisor(s): University promotor and co-promotor: dr. Erik van der Kolk, dr. Peyman Taheri, dr. Iulian Dugulan (Delft University of Technology); Wetsus supervisor(s): dr. Carlo Belloni, ir. Leon Korving
Project partners:Phosphate Recovery Theme – Wetsus
Only applications that are complete, in English, and submitted via the application webpage before the deadline will be considered eligible.
Guidelines for applicants: https://phdpositionswetsus.eu/guide-for-applicants/
