Superior removal of organic pollutants from water by cyclodextrin polymers

Project: Research project

Project Details

Description

As a consequence of population growth, continued industrialization, and climate
change, water utilities in the United States are increasingly faced with the challenge of dwindling
water supplies and are turning to drinking water resources that have been impacted by
agricultural runoff or wastewater discharges. There are two main challenges associated with
utilizing these impaired water sources for drinking water production. First, impacted water
resources contain a variety of trace organic chemicals including pesticides, pharmaceuticals, and
personal care products.1,2 Another troublesome class of emerging contaminants include
environmentally persistent perfluorinated compounds (PFCs) arising from industrial
fluoropolymer production and firefighting foams. PFC contamination led to the state of
emergency declarations in three communities in 2016, which ushered in expensive emergency
remediation efforts and bottled water distribution.3 Toxicological data for these chemicals are
limited, but significant developmental, reproductive, endocrine disrupting, and other chronic
health effects have been reported.4–6 Further, existing technologies for removing these so-called
emerging contaminants are energy intensive and not always effective.7 Second, drinking water
utilities in the United States have historically struggled with meeting disinfectant byproduct
(DBP) regulations for trihalomethanes (THMs) and haloacetic acids (HAAs).8 This burden is
expected to increase as utilities exploit source waters impaired by algal blooms and wastewater
discharges, which contain elevated concentrations of organic DBP precursors.9 These challenges
are not confined to water production in the United States and the developed world; many
developing countries face similar or exacerbated conditions resulting from intense pesticide
usage in agriculture and poor sanitation.10,11
Adsorption processes are widely employed to remove specific contaminants or contaminant
classes from water. The ideal purification adsorbent would feature rapid contaminant extraction,
high total contaminant uptake, and facile regeneration and reuse procedures. Activated carbons
(ACs) are the most widespread sorbents used to remove organic pollutants, and their efficacy
derives primarily from their high surface areas, nanostructured pores, and hydrophobicity.12
However, no single AC removes all contaminants well. Their poorly defined structures and
adsorption selectivities require empirical screening at new installations and preclude the rational
optimization of their performance. Furthermore, regenerating used AC is energy intensive
(heating to 500-900 °C) and degrades its performance relative to new AC.13 AC has a slow
uptake rate, achieving its uptake equilibrium in hours to days, and more rapid contaminant
removal requires large excesses of the sorbent. Finally, AC performs poorly for many emerging
contaminants, particularly those that are relatively hydrophilic.14 New sorbents that address the
deficiencies of AC will contribute to sustainability by providing more effective water
purification with reduced energy inputs.
StatusFinished
Effective start/end date4/1/183/31/20

Funding

  • Camille and Henry Dreyfus Foundation, Inc. (EP-16-087)

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