Design of Sustainable, Multifunctional, and Selective Water Treatment Technologies
This research project focuses on development of novel water treatment technologies using
nano-enabled biomaterials such as shrimp shells (chitosan), that are inherently more efficient, cost effective, and sustainable than traditional treatment technologies.
We utilize chitosan, a natural waste product of the shellfish industry, repurposed
to now remove inorganic pollutants such as arsenic from water in a more sustainable way than traditional treatment techniques. By cross-linking chitosan with transition metals we design adsorbents that are multifunctional, combining what is traditionally multiple steps in a treatment process into a single step, thereby reducing costs and time associated with treatment.
The adsorbents are also selective for arsenic over competing background ions such as phosphate and sulfate. By making the adsorbents selective, removal effectiveness of the target contaminant is increased, the need for a costly separation process at end of life is removed, and the recyclability of the removed contaminants as fresh feedstock is improved.
Evaluating the Influence of Soil Age and Regional Climate
on Clay Mineralogy and Cation Exchange Capacity
The traditional conception of a tropical soil is one with high amounts of kaolinite, low pH,
and low cation exchange capacity (CEC). However, approximately 60% of soils in
moist-to-humid tropical environments do not fit this description.
In this systematic study, the influence of regional climate (mean annual precipitation (MAP))
and soil age on soil clay mineralogy and cation exchange capacity was evaluated.
The findings have implications for nutrient cycling in humid tropical clay soils as well as
for accurate determination of CEC in clay-rich soils.
Through detailed analyses the smectite to kaolinite/halloysite mineral weathering reactions
were correlated with the decrease in CEC (~70 cmolc/kg to < 10 cmolc/kg).
Mean annual precipitation was found to be a major control on the rate of CEC decline, with CEC of soils in MAP of 4250 mm/yr declining at five to ten times the rate of soils in MAP of 2700 mm/yr.