Dhritikshama Roy

Dhritikshama Roy is a doctoral student in Environmental Conservation Sciences (ECS) program in Civil Engineering at North Dakota State University (NDSU). Dhriti holds MS degrees from Nicholls State University, LA (2009) and the University of Kalyani, India (2004) and a BS degree from North Bengal University, India (2002). Her MS research included treatment of aquaculture wastewater using sequencing batch reactor (SBR), pretreatment of lignocellulose for ethanol production, and study of microorganisms associated with oyster. At NDSU she is presently working on microbial biodegradation of polymers used for surface modification of metal nanoparticles for groundwater remediation.

Email: Dhritikshama.roy@ndsu.edu
Phone: (701) 231-8955

Plant-based Biopolymers for Entrapping Metal Nanoparticles for Arsenic removal: Biodegradation and Treatability Studies

Fellow: Dhritikshama Roy

Advisor: Achintya Bezbaruah, Ph.D., Assistant Professor, Department of Civil Engineering, North Dakota State University.

Eakalak Khan, Ph.D., Professor and Chair, Department of Civil Engineering, North Dakota State University

Degree Progress: Ph.D. in Environmental Conservation Sciences expected in Fall 2012.


Because of their high surface area (20–50 m 2g -1), reactivity and unique physical structure metal and metal oxide nanoscale particles have been used for remediation of various organic and inorganic contaminants including arsenic. While such nanoparticles are expected to disperse in aqueous media, they agglomerate due to magnetic and Van der Waals forces. Thus, larger particles are formed and they settle into aquifer media pores. Agglomerated particles have decreased specific surface area and, hence, lose the reactivity characteristic of individual nanoparticles. Polymers are used to overcome the problem of agglomeration by making them more dispersible via surface modification. Surface modified metal nanoparticles have shown higher reactivity towards contaminants. However, the polymers used for surface modification have been reported to be non-biodegradable in groundwater environment. Lack of biodegradation may limit the use of these polymers in groundwater. Non-biodegrable surface modifiers may themselves become 'pollutants'. It is, therefore, imperative to develop and use polymers which are easily degradable to benign end products in aqueous environment. The on-going project is focused on identification and isolation of microorganisms that will help in the process of polymer biodegradation. The surface modifiers that are being tested include conventional synthetic and plant-based polymers.


The general objective of this research is the identification and testing of PDMS and bio-polymers for entrapping nZVI for groundwater remediation. This proposal will specifically focus on the understanding of microbial degradation of the PDMS, soybean oil and other plant-based polymers and their use for the entrapment of nZVI. Appropriate modifications of bacterial consortium will be made based on the study results. The specific objectives of the study are as follows:



Dr. Achintya Bezbaruah


Advisor: Dr. Achintya Bezbaruah,

Assistant Professor of Civil Engineering, North Dakota State Uhiversity, Fargo

Phone: (701) 231-7461
Fax: (701) 231-6185

Email: a.bezbaruah@ndsu.edu

Eakalak Khan

Co-advisor: Eakalak Khan, Ph.D.,

Professor and Chair, Department of Civil Engineering, North Dakota State University

Phone: (701) 231-7717
Fax: (701) 231-6185

Email: Eakalak.Khan@ndsu.edu