(14bh) From Reactive Nano-Particles to Self-Healing Materials: Chemical Research with a Green Twist

Current and past research interests

My research is at the crossroads between the chemical, oil&gas and environmental engineering sectors, and encompasses colloid, polymer, emulsion and surface science.

Current research interests at SABIC:

Emulsions. Fouling issues in steam crackers may arise due to a number of reasons, including emulsion formation in the quench water tower. Interfacially active species were extracted and fractionated into solubility classes. The study showed the differences in the mechanisms of emulsion stabilization with the different fractions, and highlighted the correlation between interfacial film composition and morphology, and emulsion stability.

Iron-catalyzed radical polymerization. Undesired polymerization may lead to fouling issues in crackers, and should thus be avoided. The research conducted highlighted the role of iron in catalyzing polymerization of styrene and showed the correlation between solvent type and kinetics of radical polymerization.

Corrosion inhibitors. Film forming amines. Film forming amines (FFAs) are commonly used to inhibit corrosion in steam condensate systems, since they form passivating films which can act as a hydrophobic barrier against corrosive species in water. In steam systems FFAs are typically used in conjunction with neutralizing amines, which increase their solubility in water. The research conducted compared the effectiveness of different combinations of FFA and neutralizing amines in inhibiting corrosion, and investigated the factors controlling their performance.

Previous research interests:

Reactive polymer coated nano-particle optimization for groundwater remediation (PhD research). Nano zero-valent iron (nZVI) remediation technology is used to treat aquifers contaminated by chlorinated compounds and heavy metals, which react with iron forming less harmful compounds. The success of nZVI technology relies on adequate particle delivery to the polluted areas, and this was the focus of my research. Particle transport is largely influenced by the surface properties of the particles. Therefore, I investigated the effect of polymer coatings used to stabilize iron particle suspensions on the transport of particles through aquifers having different mineral compositions and water chemistries. I probed the forces of interaction between the particles and the substrates, because large adhesive forces hinder particle transport. In my study I utilized wet-water chemistry to synthesize and electrodeposited iron nano-particles on AFM probes to measure the adhesion forces between single particles and model mineral substrates under no-flow conditions. Furthermore, I probed sorption phenomena under laminar flow conditions using QCM-D. The particles synthesized were characterized using SEM, EDX, XPS and XRD to assess their morphology and composition before and after prolonged exposure to aqueous media, simulating groundwater conditions. My research showed the importance of hydration forces in the interactions between nZVI and mineral surfaces, and demonstrated that polymer coatings with a cationic counter-ion could inhibit particle attachment onto silicate minerals in a wide range of water chemistries.

Emulsions in the upstream oil&gas sector. Problematic emulsions are common in the upstream sector, and specifically in the oil sands industry. The collaborative research I conducted at the University of Alberta demonstrated the role of a specific asphaltene sub-fraction in stabilizing emulsions, and highlighted the factors controlling emulsion stability when using model compounds of asphaltenes. My research further focused on the use of polymeric demulsifiers to destabilize problematic emulsions. My research correlated demulsification performance to the chemistry of the demulsifiers and to their effect on the interfacial films, namely on their compressional and shear rheological properties, and on their morphology (as probed with BAM at the liquid-liquid interface, and with AFM of Langmuir-Blodgett films). A similar approach was successfully adopted to study emulsions stabilization by pH and temperature responsive NIPAM (poly(N-isopropylacrylamide)) micro-gels.

High performance polymer-based non-Newtonian gels: effect of cross-linker and polymer type on the shear and thermal stability of the gels. I developed polymeric gels for enhanced oil recovery applications at high temperature and high shear regimes. I engineered self-healing gels with synthetic and natural polymers, cross-linked with a variety of cross-linkers, and determined the best combination of polymer, cross-linker and water chemistry yielding a highly viscous and stable gel at elevated temperature and high shear rates. Importantly, I was able to produce an additive capable of generating radicals that could break the gel on demand with controlled kinetics, thus reducing its viscosity to extremely low values after a desired time period.

Future research scopes

My objective is to draw knowledge from the oil&gas and chemical sectors to produce materials that can be used for the treatment and the containment of contaminants, investigating at the nano-scale level the factors controlling their performance. My interests further extend to fouling phenomena, which are a major cause for energy losses in industrial processes. I intend to expand on my current research and engineer antifouling surfaces for diverse applications, ranging from petrochemical processes to water treatment using membranes.

Teaching Interests:  

As a doctoral researcher at the University of Toronto I had the opportunity to support teaching for a total period of four years in the following disciplines:

• Engineering Mathematics;
• Engineering Graphics;
• Groundwater Flow and Contamination;
• Hydrology and Hydraulics.

I thoroughly enjoyed the role of teaching assistant, and I would be thrilled to pursue my vocation for teaching in the years to follow, engaging in either advanced or undergraduate courses.

Publications

Kuldeep Wadhwa, Juul Hennissen, Sharankumar Shetty, Erica Pensini, Carlo Geijselaers. Influence of the substitution of functional groups on the inhibition efficiency of TEMPO analogues on vinyl polymerization. To be submitted.

Erica Pensini, Fabrice Cuoq, Roy van Lier, Wolfgang Hater, Patrick Kraft, Tobias Halthur. Enhanced corrosion resistance of metal surfaces by film forming amines: a comparative study between cyclohexanamine and 2-(diethylamino)ethanol-based formulations. Submitted to I&EC.

Erica Pensini, Leo Vleugels, Martijn Frissen, Kuldeep Wadhwa, Roy van Lier, Gerard Kwakkenbos. A novel perspective on emulsion stabilization in gasoline crackers. Submitted to Colloids and Surfaces A.

Fan Yang, Plamen Tchoukov, Erica Pensini, Tadeusz Dabros, Jan Czarnecki, Jacob Masliyah, and Zhenghe XuAsphaltene Subfractions Responsible for Stabilizing Water-in-Crude Oil Emulsions. Part 1: Interfacial Behaviors. Energy Fuels, 2014, 28 (11), pp 6897â??6904.

Zifu Li, David Harbottle, Erica Pensini, To Ngai, Walter Richtering, and Zhenghe Xu. Fundamental Study of Emulsions Stabilized by Soft and Rigid Particles. Langmuir, 2015, 31 (23), pp 6282â??6288.

Jiebin Bi, Fan Yang, David Harbottle, Erica Pensini, Plamen Tchoukov, Sébastien Simon, Johan Sjöblom, Tadek Dabros, Jan Czarnecki, Qingxia Liu, and Zhenghe Xu.Interfacial Layer Properties of a Polyaromatic Compound and its Role in Stabilizing Water-in-Oil Emulsions. Langmuir, 2015, 31 (38), pp 10382â??10391.

E. Pensini, D. Harbottle, F. Yang, P. Tchoukov, Z. Li, I. Kailey, J. Behles, J. Masliyah, Z. Xu. Demulsification Mechanism of Asphaltene-Stabilized Water-in-Oil Emulsions by a Polymeric Ethylene Oxideâ??Propylene Oxide Demulsifier. Energy & Fuels, 2014, 28 (11), pp. 6760-6771.

E. Pensini, B.E. Sleep, C. Yip, D. Oâ??Carrol. Effect of water chemistry and aging on iron - mica interaction forces: Implications for iron particle transport. Langmuir, 2012, 28 (28), pp. 10453â??10463.

E. Pensini, B.E. Sleep, C. Yip, D. Oâ??Carrol. Forces of interactions between bare and polymer coated iron and silica: effect of pH, ionic strength and humic acids. Environ. Sci. Technol., 2012, 46 (24), pp. 13401â??13408.

E. Pensini, B.E. Sleep, C. Yip, D. Oâ??Carrol. Forces of interaction between fresh iron particles and iron oxide (magnetite): Effect of water chemistry and polymer coatings. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2013, 433, pp. 104â??110.

E. Pensini, B.E. Sleep, C. Yip, D. Oâ??Carrol. Carboxy-methyl cellulose binding to mineral substrates: Characterization by atomic force microscopy based - force spectroscopy and quartz-crystal microbalance with dissipation monitoring. Journal of Colloid and Interface Science, 2013, 402, pp. 58-67.

E. Pensini, B.E. Sleep, C. Yip, D. Oâ??Carrol. Forces of interaction between iron particles and aluminum-silicates: Effect of water chemistry, polymer coatings and aluminum-silicate composition. Journal of Colloid and Interface Science, 2013, 411, 8-15.