Characterization of physico-chemical properties of nano-sized particulates and their implications on transport behavior

Open Access
- Author:
- Azam, Sikandar
- Graduate Program:
- Energy and Mineral Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 06, 2024
- Committee Members:
- Jeremy Gernand, Program Head/Chair
Suresh Iyer, Outside Unit & Field Member
Shimin Liu, Major Field Member & Dissertation Advisor
Sekhar Bhattacharyya, Chair & Dissertation Advisor
William Groves, Major Field Member - Keywords:
- Nano-Sized Particles
Respirable Coal Mine Dust
Environmental Interation
Particle Characterization
Particulate Transport Modeling
Particulate Moisture Interaction - Abstract:
- Modern society is heavily dependent on coal mining for its energy generation, contributing 27% to primary energy consumption and 36% to global electricity generation. Despite its economic importance, coal mining poses severe health risks, particularly respiratory diseases like coal workers' pneumoconiosis (CWP) and silicosis. Recent resurgences of CWP, especially in central Appalachia, highlight the inadequacy of current dust control measures. The recent increase in the awareness of respirable coal mine dust nanoparticles (RCMD NPs) demands urgent attention due to their unique properties and increased toxicity compared to larger particles. Advanced techniques such as scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used to identify and characterize nano-sized coal dust particles. Electron Paramagnetic Resonance (EPR) spectroscopy analyzed the characteristics and stability of Environmentally Persistent Free Radicals (EPFRs) in nano-sized coal dust. Dynamic vapor sorption (DVS) techniques were employed to investigate the interaction of these particles with moisture. Additionally, Computational Fluid Dynamics (CFD) and numerical modeling were utilized to simulate the transport, deposition, and moisture interactions of nano-sized coal dust particles. The findings confirm the presence of nano-sized coal dust particles in mining environments. EPFRs in coal dust were found to be remarkably stable, persisting for several months, and were primarily oxygenated carbon-centered or a mixture of carbon and oxygen-centered. The interactions of these free radicals with the human cells pose greater health risks to miners augmented by the prolonged suspension and deeper lung penetration of the nano-sized particles. CFD simulations revealed that moisture significantly alters the transport and deposition behaviors of nano-sized particles, corroborating experimental observations. This research has highlighted the noteworthy presence of nano-sized dust particles in the coal mine atmosphere which could have grave consequences on worker health. The study underscores the critical need for heightened attention and monitoring concerning nano-dust-related health issues in the mining industry. Given the unique challenges posed by these nano-particulates, the findings emphasize the importance of considering the interactions of nano-sized particulates with environmental moisture in dust control measures. These interactions may necessitate changes in ventilation systems to manage the altered flow and deposition patterns effectively. A deeper understanding of these dynamics could lead to more effective dust control strategies, thereby significantly reducing the health risks associated with respirable coal mine dust. The findings suggest a paradigm shift in how dust exposure is assessed and managed in the mining industry, aiming to enhance worker protection. In summary, this research supports a paradigm shift in how dust exposure is assessed and managed in the mining industry, aiming to enhance worker protection. The integration of experimental techniques with CFD and numerical modeling has provided a comprehensive understanding of the behavior of nano-sized coal dust particles in mining environments, paving the way for these advancements. The effectiveness of using particle number and specific surface area as standards for nanoparticles is significantly higher compared to relying solely on particle mass, as they might have negligible mass but large numbers and specific surface areas. Further research is essential to grasp the long-term effects of RCMD NPs and to formulate mitigation strategies that can effectively minimize occupational exposure and associated diseases among miners.