Enquiries are welcome from potential PhD students interested in the research themes listed below under Current Research Interests. 

PhD studentships are available every year through a competitive process. The studentships are managed by the School of Engineering, the Institute for Infrastructure and Environment, and the College of Science and Engineering. 

Applicants interested in applying for a University-administered award should contact me ([email protected]) no later than early autumn to begin discussions. Application deadlines vary from mid January to late March.

Applications are also welcome from self-funded PhD students holding awards from CONACyT, CONICYT, China Scholarship Council, etc.

Postdoctoral applicants interested in applying for competitive awards (e.g., Marie Skłodowska-Curie Fellowships, Newton International Fellowships, NSERC Postdoctoral Fellowships, etc.) should contact me to discuss potential projects.

Dr Santiago Romero-Vargas Castrillón is a Senior Lecturer in Chemical Engineering at the University of Edinburgh, appointed to the Institute for Infrastructure and Environment. Before coming to Edinburgh he served as assistant professor in the Department of Civil, Environmental, and Geo- Engineering at the University of Minnesota (2014-2018). At Minnesota he also held a graduate faculty appointment in the Department of Chemical Engineering and Materials Science. He received a PhD in chemical engineering from Princeton University (2012), and carried out postdoctoral research in environmental engineering at Yale University (2012-2014). His lab is currently engaged in research focusing on colloid and interface science in environmental systems, membrane separations, membrane transport processes, and the environmental applications of 2D nanomaterials.

Member, Early Career Editorial Board for Chemical Eng. Journal Advances (Elsevier) 2021

Member, RSE Young Academy of Scotland                                                             2021

Selection as Associate, Institute on the Environment, University of Minnesota          2016

Current Membership in Professional Organisations

American Chemical Society (ACS) 2014 – present

American Institute of Chemical Engineers (AIChE) 2008 – present

Association of Environmental Engineering and Science Professors (AEESP)  2014 – present

European Membrane Society (EMS)  2019 – present

North American Membrane Society (NAMS)  2015 – present

Associate Member of the EPSRC Peer Review College  2020 – present

My research focuses on colloid and interface science in environmental systems, membrane separations, membrane transport processes, and the environmental applications of 2D nanomaterials. Research themes of interest to us include:

• Membrane fouling and fouling mitigation: we are interested in gaining a fundamental understanding of the mechanisms underlying fouling during membrane-based water/wastewater treatment (e.g., reverse osmosis, nanofiltration, and ultrafiltration). Further, in collaboration with Panton-McLeod, we are developing a cleaning formulation to remove foulant layers from membranes. This research theme is multidisciplinary, drawing from fluid mechanics and mass transfer, and colloid/interface science.
• Bioadhesion: we use state-of-the-art surface techniques such as AFM to investigate bioadhesion, the crucial first step in biofilm formation and biofouling. Our recent work has focused on elucidating the adhesion mechanisms of bacteria on polymeric membranes, as well as on interfaces functionalised with biocidal nanomaterials such as graphene oxide.
• Environmental interactions of nanoscale materials: we are interested in describing the nanoscale interactions of nanoparticles with biological membranes, with the goal of gaining an understanding of their toxicity and environmental impact. Our recent work in this area used AFM-based force spectroscopy to measure, directly and in real time, the interactions of graphene oxide nanosheets with bacterial cell membranes. Future work in this area will focus on nanoplastics.
• Membrane transport processes: we use molecular simulation to investigate transport mechanisms in nanopores and confined geometries. This research is undertanken with a view towards understanding transport and selectivity in membrane materials.

Selected Publications: (A complete list is available in Google Scholar)

• S. BinAhmed, R. M. Hozalski, S. Romero-Vargas Castrillón, Feed Temperature Effects on Organic Fouling of Reverse Osmosis Membranes: Competition of Interfacial and Transport Properties. ACS ES&T Engineering 2021, 1, 591–602

• S. BinAhmed, A. Hasane, Z. Wang, A. Mansurov, S. Romero-Vargas Castrillón, Bacterial adhesion to ultrafiltration membranes: role of hydrophilicity, natural organic matter, and cell-surface macromolecules, Environ. Sci. Technol. 2018, 52, 162-172

• M. Karzar Jeddi, S. Romero-Vargas Castrillón, Dynamics of water monolayers confined by chemically heterogeneous surfaces: observation of surface-induced anisotropic diffusion, J. Phys. Chem. B 2017, 121, 9666-9675

• S. Romero-Vargas Castrillón, F. Perreault, A. F. Faria, M. Elimelech, Interaction of graphene oxide with bacterial cell membranes: insights from force spectroscopy, Environ. Sci. Technol. Lett. 2015, 2, 112-117. Highlighted in Science Editors’ Choice (15 May 2015)

Recent Research Funding: See Projects

Invited talks, conference presentations, and symposium organisation: See Activities

• Member of the Chemical Engineering Discipline Executive Group (2021 – present)
• Laboratory Manager for William Rankine 2.14, 2.17, and 2.18 (2019 – present)

University of Edinburgh

As Course Organiser, or major contribution

CHEE09020 Chemical Engineering Thermodynamics 3, Semester 1 (AY20-21)

• Nominated for a 2021 EUSA Teaching Award (in the “Teacher of the Year” category)

CHEE09017 Thermodynamics and Unit Operations (Thermodynamics module), Semester 1 (AY19-20)

CHEE08001 Chemical Engineering 1 (Mass balances, lab supervision), Semester 2 (AY18-19, 19-20)

Other contributions

CHEE10009 Chemical Engineering Study Project 4 (AY19-20, 20-21)

CHEE11017 Chemical Engineering Research Project 5 (AY19-20, 20-21)

CHEE11031 Chemical Engineering Industrial/Overseas Research Project 5 (AY19-20, 20-21)

CHEE10002 Chemical Engineering Design: Projects 4 (AY18-19, 20-21)

University of Minnesota

All as Course Organiser (F: fall semester; S: spring semester)

CEGE 5180 Special Topics: Membrane Science & Technology, F 2016

CEGE 8504 Theory of Unit Operations, S 2015, S 2016, S 2017, S 2018

CEGE 4502 Water and Wastewater Treatment, F 2015, F 2017

CEGE 4011/5570 Design for Sustainable Development: Nicaragua, May-June 2017