Date of Award

12-15-2014

Document Type

Open Access Dissertation

Department

Civil and Environmental Engineering

First Advisor

Yeomin Yoon

Abstract

Untreated or insufficiently treated pharmaceuticals and endocrine disrupting compounds (EDCs) as well as heavy metals have influenced the ecosystem and their exposures in the water system have threatened human health; causing cancers and adverse health effect to immune system. While various water treatment techniques have been applied to solve this problem, adsorption has been considered as one of the most efficient and manageable water purification techniques. Advanced analysis methods for aqueous contaminants have improved comprehension, allowing proficiency about the fate of trace leveled emerging contaminants, thus allowed to reveal the adsorption mechanisms of each pollutant. This dissertation focuses on the investigation of adsorption for micro-pollutants in aquatic environment via the application of different types of carbonaceous (powdered activated carbon, carbon nanotubes, and biochars) and biodegradable (chitosan) adsorbent. The effect of water chemistry conditions such as pH, concentration of ionic strength induced species and natural organic matters were considered as significant factors to increase or decrease the adsorption capacity of each adsorbent. This study also illuminates the use of biochar, byproduct of bio-oil, with simple chemical activation as an efficient adsorbent for pharmaceutical and EDCs removal. In-depth analysis about adsorption between these micro-pollutants and biochars was performed by characterization of physicochemical properties by nuclear magnetic resonance analysis in conjunction with molecular modeling subsequently interpreting the binding energy. Aromaticity and composition of carbonaceous structure of adsorbent controlled the adsorption capacity, while hydrophobicity of adsorbates influenced the adsorption affinity toward the adsorbents. More specifically, the presence of adsorption competitors resulted in less effective binding due to a combination of less favorable binding energy, polarity, and π-energy with the adsorbent and electrostatic repulsion from the cosolutes that occupied adsorption sites.

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