Recovery of rare earth elements (REEs) from coal fly ash (CFA) is a promising resource recovery and waste recycling option that might bring about significant economic and environmental benefits. However, many challenges need to be addressed in order to develop cost effective and environmentally friendly techniques for REE recovery from CFA. The overall goal of this dissertation is to develop a synergistic approach to simultaneously achieve REE recovery from CFA and waste reduction.

The tropical Pacific is a dominant influence on global climate, from interannual to glacial-interglacial timescales. How this system will respond to anthropogenic greenhouse gas forcing, however, remains an area of large uncertainty. In order to better our understanding of how the tropical Pacific ocean-atmosphere system has responded to greenhouse gas forcing in the past, I have generated new reconstructions of sea surface temperature (SST) in the central equatorial Pacific over the last ~150,000 years.

Biomass burning is a significant source of gas- and particle-phase carbon in the atmosphere. It emits thousands of volatile organic compounds (VOCs) that can contribute to the formation of secondary organic aerosol (SOA). Recent studies have shown that furans are an important class of VOCs and constitute a significant portion of biomass burning plumes.

Organic aerosols (OA) have long been thought to only scatter incoming solar radiation and have a cooling effect on climate. However, a fraction of OA, referred to as brown carbon (BrC), absorbs light in the lower visible to ultraviolet range. BrC can be emitted from incomplete combustions and can also be generated through secondary processes. The radiative impact of BrC on climate is difficult to assess owing to the lack of knowledge about emissions and the evolution of BrC aerosol.