Dr. Jinasena Hewage

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My research with undergraduates is multidisciplinary: Material Sciences, Analytical Chemistry, Natural Products, Computational/Theoretical Chemistry, etc.

Unraveling the phytochemistry, biological, and pharmacological activities of plants native to North Dakota

The use of plant materials with therapeutic properties for various diseases has been well accepted and utilized by various communities throughout history in different parts of the world. The therapeutic properties of various plants have been identified to treat different diseases as the results of thousands of years of practice carried forward from generation to generation. North Dakota is home to a variety of such native plants which are still to be unraveled in their phytochemistry, biological, and pharmacological activities. The main objectives of this project are to explore such plants (databases) that have been used for various treatments, identify phytochemistry, and bioactive compounds with therapeutic properties, and to the pharmacological and biological activities.

The development of ZnO-based catalysts for the photodegradation of pharmaceutical waste and organic pollutants.

The development of solid-state materials is a key to the advancement of science in every aspect of applications, from electronics to medicine. Hence the development of novel materials has played a major role in modern technological developments. 

Experimental procedures involve both liquid-phase synthesis and solid-phase synthesis. In the liquid phase synthesis, the initial reactants are in the liquid phase, while the final product results in a solid material. In solid-phase synthesis, reactants are in solid phases; they are ground, mixed, and heated up to high temperatures (probably above the melting temperature).

The synthesis of catalytic materials, both conventional and nano, is one of the most promising areas that need further advancement. Development and advancement in photodegradation of environmental pollutants by photocatalysts increase environmental safety: Degradation of industrial organic waste, purification of water bodies, etc. My recent research has mainly focused on synthesizing ZnO-based materials as photocatalysts in various applications including the degradation of organic pollutants in wastewater, and pharmacological waste. Among the various semiconductors available, TiO₂ and ZnO are known as the best photocatalysts for the degradation of a large number of environmental contaminants due to their high photosensitivity, stability, and large band gap. When illuminated with an appropriate light source, the photocatalyst generates electron/hole pairs with free electrons produced in the empty conduction band leaving positive holes in the valence band. These electron/hole pairs are capable of initiating a series of chemical reactions that eventually mineralize the pollutants. Moreover, the formation of non-toxic, harmless, and eco-friendly end products represents another significant feature of this process. The extent of the mineralization is the most important criterion for assessing the feasibility of any oxidation process as incomplete oxidation may lead to an intermediate, which may be more toxic than the parent pollutant. Oxidative decolorization of these compounds by conventional methods such as ozonation is expected to be more difficult even for the simple monoazodyes. The objective of this research is to develop efficient ZnO-based photocatalysts with the use of zinc oxide as a starting material by co-doping with common metal ions and noble metals to improve the properties of zinc oxide to overcome the drawbacks and increase the efficiency of photocatalysis.