(4fo) Electrochemical Techniques in Separation Processes

Electrocatalysis are vital to fulfill increasing demand for energy. Fuel cells and lithium-ion batteries (LIBs) are highly gaining interest in recent years. Specially, LIBs proved to be reliable devices which have been used widely in cell phones and electric vehicles (EVs). U.S. Energy Information Administration (EIA) predicts the cumulative LIB packs for EVs generated between 2015 and 2040 will be as many as 21 million. Although the LIBs in EVs are expected to last at least 8–10 years, handling of LIBS at their end of life (EOL) is crucial and required to be recycled efficiently due its potential hazard and high contents of valuable material. While these resources of sustainable energy are vital in protecting our environment, even by increasing use of them, the requirement to stop global warming does not meet. The change in our climate urgently requires a rapid removal of atmospheric CO2 emitted from energy-related sources.

Recycling of hazardous material is not limited to LIBs or CO2. There are several other industries dealing with handling the wastes. An example would be in paper and pulp industry where black and weak liquor, a waste from boiler and pulp mills, required to be dumped safely. However, rich content of lignin as well as sodium make them resources of valuable material and can be recycled efficiently.

Given these challenges in energy resources and considering environmental, electrochemistry is a promising technique and can play a predominantly role not only in production of sustainable energy, but in solving and addressing the challenges in remediation of our environment due to carelessly usage of conventional type of energy resources. It can be utilized to recover materials from complex compounds like lithium, nickel and cobalt present in LIBs, Additionally, electrochemical methods have also proven valuable in the recycling of hazardous gases and liquid mixtures.

My research will be focused to address these issues. I am not only interested in materials discovery and design by implementing multi-scale molecular modeling (MSMM), but in experimental techniques to study the kinetics of these complex reactions. While MSMM approaches allow to establish structure vs. properties and structure vs. performance relationships, lab observations facilitate the validation of the results. The main goal is to provide computational guidance for material design and lab scale validation to accelerate the identification of promising materials for the target applications in a trustable and applicable procedure. My general research plan to approach these projects are based on my procedure and findings in my dissertation and postdoctoral studies as well as my industrial experiences.

In my Ph.D., I studied the reaction kinetics of ammonia dissociation on platinum and compared it to iridium. I successfully demonstrated that the mechanism of ammonia dissociation on platinum is different from iridium. On platinum, the mechanism involves hydrazine formation followed by hydrazine dehydrogenation to molecular nitrogen. However, for iridium, ammonia undergoes successive dehydrogenation to form atomic nitrogen, followed by N-N bond formation to N2.

In my postdoc studies, I extended my PhD studies and addressed the effect of solvent with applied electric field in electrochemical systems. I studied the solvent effect with external electric field by including the polarizability of the interface which is implemented in classical molecular dynamics (cMD) and quantum mechanics (QM) techniques along with explicit solvent. My results show that the electric field affects the orientation of explicit water molecules. Thus, the hydrogen bonds between adsorbates and water are completely different and have significant effects on adsorption specifically in layers close to the surface (double layer).

Along with these scientific experiences, I will use my expertise in industry and project management to monitor the whole project from estimation of costs at the pre-start phase to time plan, material supply, and human resources. This ensures the efficiency in cost and time in performing the project. My versatile expertise with management skills have given me a unique ability to fundamentally and critically analyze the results in a coherent and conceptual project plan. The management art of performing satisfactory on two simultaneous jobs while dealing with demand of family life bolster my intension and enthusiasm toward my aims.

Research Interests

Electrochemical methods for end of life (EOL) recycling of Lithium Ion Batteries (LIBs)

Pyrometallurgy and hydrometallurgy are the two most common process in recycling LIBs. In general, hydrometallurgical processes are considered cleaner and less costly than the high temperature processes. However, A challenge in this process is to separate the metals from leachate which needs further costs.

There are electrochemical methods for leaching valuable metals of LIBs which are dominated by the combination of sulfuric acid (1 to 4 M H2SO4) and hydrogen peroxide (1 to 15 wt.% H2O2); however, it is difficult to obtain a satisfactory recovery rate of Li (most of the reported recovery rates are less than 80%).

Using of new material to selectively separate these metals are reported more recently. In one example, in order to selectively extract Li+ from the leaching solution of spent lithium-ion batteries, benzo-15-crown-5 ether (B15C5) is synthesized and used as a lithium extractant.

The project that I define in my research group is the enhancement of the electrochemical process by finding the effect of aqueous media on the thermodynamics and kinetics of reaction. Additionally, materials discovery efforts to identify novel catalyst materials to selectively extract the valuable metals is the other project that I envision to work on.

CO2 conversion to valuable products

The conversion of CO2 into useful chemical feedstocks has been a target of carbon capture and sequestration (CCS). As CO2 is the fully oxidized form of carbon, energy must typically be supplied to convert the carbon into a more reduced form, as it appears in most organic molecules. Verity of parameters affects this reaction from morphology, facet and material of electrocatalyst to electrolyte composition and pH. It has been shown that copper is the most reactive electrocatalyst in CO2 reduction to hydrocarbons, aldehydes and alcohols. To better understand the reactivity of Cu and how it can be tuned to achieve greater selectivity, stability, and efficiency research has been done which tried to answer to two main challenges in electrode and electrolyte but still a long way to address these challenges. It is my plan to work on in my research group as well:

Electrode: While Cu has been proved to be major reactive catalyst in CO2 reduction, there are other several emerging classes of catalysts that hold the potential to break scaling relations between reaction intermediates, including stable alloys, single atom catalysts, (doped) carbon materials, metal organic frameworks (MOFs), and so on.

Electrolyte: The competing HER (hydrogen evolution reaction) remains a significant issue for CO2 reduction in aqueous systems. Effect of Solvent in this part is more obvious and needs to be addressed. The choice of electrolyte can have a huge impact on CO2 reduction performance; the composition and concentration of anions and cations can cause changes in the electrostatic interactions, buffer capacity, pH, and availability of proton donors which ultimately affect the selectivity toward CO2 reduction.

Lignin conversion to valuable product through electrochemical techniques

Another project that I plan to study is the utilization of bleeding liquid of scrubber's outlet(rich and saturated liquid) to produce valuable chemicals. Scrubbers are used for washing the contaminants from flue gas into the liquid stream. One of the applications of scrubbers is in paper and pulp industry where black liquor which is generated in pulp mills during kraft pulping of wood or non-wood raw materials used as scrubbing liquid in the form of weak liquor.

Black liquor contains approximately 25%–41% lignin and 18%–23% sodium and other dissolved organics (hemicelluloses, cellulose, extractives, etc.), and inorganics. Due to the presence of large amounts of organics, black liquor can be considered as a renewable resource. Electrochemical conversion of waste lignin from the black or weak liquor is an alternative renewable process for generating industrial chemicals that may afford better control over conversion than other catalytic or thermochemical processes because the electrode potential, and hence the reaction energetics, can be controlled. The mechanism of lignin oxidation is complex and likely follows several possible pathways.

Teaching Interest

Based on my teaching, research and industrial experiences, I am capable of operating teaching all core courses in chemical engineering curriculum like: Thermodynamics, Fluid Mechanics and Dynamics, Transport Phenomena, Kinetics and Reactor Design, and Unit Operations. In addition, I would like to integrate research and teaching by developing a new “Industrial pollution control” course. This course will focus on air pollution control, water pollution control, solid waste, and hazardous waste management. Concepts from environmental regulations are vastly used in sustainable energy research and all part of chemical and petroleum industries. I also feel comfortable teaching another optional course like “electrochemical techniques” including different techniques in analytic electrochemistry, industrial electrochemistry, transport phenomena in combination with applied voltages and surface chemistry. The other course I am thinking of is “Molecular modeling, basics and concepts”. It starts from classical thermodynamics moving to statistical thermodynamics and then advanced to different strategies in molecular modeling including (cMD) to Ab Initio methods and QM.