Dear CEE Community,

Please come join us to learn how to treat water with coffee grounds from our own expert Jessica Steigerwald.

When/where: Thursday (2/9), 3:30. SMI (Smith Hall) 211.

Zoom: https://washington.zoom.us/j/96670347080

Schedule and recordings: https://depts.washington.edu/watersem/

Title: Treating Water with Coffee Grounds: Development of a Novel Biochar-Molecularly Imprinted Polymer Composite for Targeted Removal of Perfluoroalkyl Substances in Water Treatment Applications

Abstract: Per- and polyfluoroalkyl substances (PFAS) are a class of emerging contaminants which have received considerable research and regulatory attention in the last decade because of their toxicity, persistence, and prevalence in environmental and human reservoirs. Wastewater is an important source of perfluoroalkyl acids (PFAS) to environmental waters. PFAS are poorly removed during conventional wastewater treatment and only moderately removed by non-selective adsorbents (e.g., activated carbon). Thus, there is a need for a more selective PFAS removal method for wastewater treatment. Molecularly imprinted polymers (MIPs) enable selective adsorption of trace organics (e.g., PFAS) by templating polymerization with a target compound; however, MIP morphology limits use for wastewater treatment. To overcome this obstacle, a perfluorooctanesulfonate (PFOS)-templated MIP was immobilized on a spent coffee grounds biochar—an eco-friendly activated carbon alternative—via radical initiated polymerization. Vinylbenzyl trimethylammonium chloride (VBTAC) and/or 2-(trifluoromethyl)acrylic acid (TFMA) served as functional monomers for MIP synthesis.  First, biochar surfaces were functionalized with –NH MIP attachment points via: (i) electrophilic aromatic substitution followed by reduction; or, (ii) heat-catalyzed addition of melamine. Melamine-modified biochar functionalized with VBTAC-MIP (BC-M@MIP-V) demonstrated high PFOS selectivity (K_selectivity of 4.52 for perfluorobutanesulfonic acid and 3.76 for perfluorooctanoic acid) and PFAA adsorption comparable to unmodified biochar in ultrapure water (0.043 and 0.039 mg PFAA/g*g/m², respectively). Adsorption by BC-M@MIP-V increased by 0.012 mg PFAA/g*g/m² in synthetic wastewater due to reduced MIP swelling and non-specific binding. Single cycle regeneration of the BC@MIP composites suggest long material lifetimes are possible. These novel, selective adsorbent presents a potential alternative for effective wastewater PFAS treatment.

Bio: Jessica Steigerwald is a PhD student in Environmental Engineering working with Prof. Jessica Ray. Her research focuses on development and testing of materials for removal of emerging organic contaminants from water. Jessica Steigerwald received her B.S. from Oregon State University (2018) and her M.S from the University of Washington (2022), both degrees in Environmental Engineering. Between receiving her undergraduate degree and starting graduate school, Jessica worked at Arcadis focused on remediation of PCBs and organic solvents in soil, groundwater, and surface waters. In her free time Jessica enjoys running and skiing with her husky dog, Quin