CHBE 565-International Paper Co Seminar-Prof. Varong Pavarajarn, Chulalongkorn University (Host: Prof. Chris Rao) "When Industry Asks "How?", Scientists Ask "Why?": Molecular Interactions Behind Carbon Capture and Surface-Controlled Chemical Transformations"

Abstract: Chemical engineering research is shaped not only by scientific curiosity, but also by the research ecosystem, in which it is conducted. Many scientific investigations begin with fundamental questions and evolve toward practical applications. In Thailand, where industries often focus on technology adoption and adaptation, many engineering research projects originate from industrial and societal challenges, and their success is frequently measured by the potential for near-term technological impact. Despite the different starting points, this seminar explores how practical engineering problems can serve as gateways to fundamental scientific discovery.

Drawing on research inspired by Thailand’s carbon transition and environmental challenges, I will demonstrate how application-driven questions, such as “How can we reduce the energy requirement of carbon capture?”, “How can we convert captured carbon dioxide directly into valuable products, without first releasing it from the capture medium?”, and “How can we control toxicity of products from photocatalytic degradation of contaminated water?” naturally evolved into deeper scientific questions concerning molecular interactions, interfacial phenomena, and reaction mechanisms. These case studies illustrate that solving practical engineering problems often requires uncovering fundamental molecular mechanisms that would otherwise remain hidden.

The first case study examines carbon dioxide capture using amine solvents, where the practical objective of reducing the cost and energy requirements led to the integration of CO₂ mineralization and solvent regeneration, and a mechanistic investigation of the destabilization of protonated amines. The second case study is an extension of the first case, focusing on the direct electrochemical conversion of carbon dioxide captured in carbamate form. Using atomic force microscopy, we investigate how carbamate molecules interact with copper surfaces and how pH, applied potential, and surface structure influence adsorption and catalytic behavior. The third case study addresses photocatalytic degradation of residual herbicide in water, where differences in photocatalytic activity among ZnO crystals with different exposed facets prompted a detailed study of facet-dependent adsorption using atomic force microscopy under liquid conditions. The results reveal how surface structure and interfacial interactions govern reaction pathways and consequently influence the toxicity of the degraded products.

Although these projects originate from diverse application areas, they share a common scientific foundation. In each case, macroscopic process performance is controlled by molecular interactions at solid-liquid interfaces. Understanding these interactions not only explains unexpected experimental observations, but also provides new opportunities for rational process and catalyst design.

Through these examples, I will argue that industrially motivated research and curiosity-driven science are not competing approaches. Rather, impactful advances in chemical engineering can emerge when practical “How?” questions are reformulated into fundamental “Why?” questions.

Biography: Varong Pavarajarn is a Professor in the Department of Chemical Engineering at Chulalongkorn University, the oldest and first university in Thailand. His research interests include interfacial phenomena, catalysis, and sustainable chemical processes. More recently, his research has focused on uncovering the molecular mechanisms underlying practical engineering problems in carbon capture, catalysis, and sustainable chemical processes.

He has led and participated in many research projects in collaboration with industry and government agencies. He is the founder and coordinator of the Thailand CCUS Technology Development Consortium, which brings together leading companies from Thailand’s energy, petrochemical, cement, steel, and industrial gas sectors to accelerate the development and deployment of carbon management technologies.

Professor Pavarajarn received his Ph.D. in Chemical Engineering from Oregon State University and has spent his academic career at Chulalongkorn University, where he is actively engaged in research, teaching, and the development of international engineering education programs.