Publications by authors named "William A Tarpeh"

Recovering nitrogen (N) from wastewater is a potential avenue to reduce reliance on energy-intensive synthetic nitrogen fixation via Haber-Bosch and subsequent treatment of N-laden wastewaters through nitrification-denitrification. However, many technical and economic factors hinder widespread application of N recovery, particularly low N concentrations in municipal wastewater, paucity of high-efficiency separations technologies compatible with biological treatment, and suitable products and markets for recovered N. In this perspective, we contextualize the challenges of N recovery today, propose integrated biological and physicochemical technologies to improve selective and tunable N recovery, and propose an expanded product portfolio for recovered N products beyond fertilizers.

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Electrification to reduce or eliminate greenhouse gas emissions is essential to mitigate climate change. However, a substantial portion of our manufacturing and transportation infrastructure will be difficult to electrify and/or will continue to use carbon as a key component, including areas in aviation, heavy-duty and marine transportation, and the chemical industry. In this Roadmap, we explore how multidisciplinary approaches will enable us to close the carbon cycle and create a circular economy by defossilizing these difficult-to-electrify areas and those that will continue to need carbon.

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Chlorine has been supplied by the chlor-alkali process that deploys dimensionally stable anodes (DSAs) for the electrochemical chlorine evolution reaction (ClER). The paramount bottlenecks have been ascribed to an intensive usage of precious elements and inevitable competition with the oxygen evolution reaction. Herein, a unique case of Ru-O active motifs anchored on Magnéli TiO (Ru-TiO) via a straightforward wet impregnation and mild annealing is reported.

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Nitrogen in wastewater has negative environmental, human health, and economic impacts but can be recovered to reduce the costs and environmental impacts of wastewater treatment and chemical production. To recover ammonia/ammonium (total ammonia nitrogen, TAN) from urine, we operated electrochemical stripping (ECS) for over a month, achieving 83.4 ± 1.

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Electrochemical methods can help manage sulfide in wastewater, which poses environmental and health concerns due to its toxicity, malodor, and corrosiveness. In addition, sulfur could be recovered as fertilizer and commodity chemicals from sulfide-containing wastewaters. Wastewater characteristics vary widely among wastewaters; however, it remains unclear how these characteristics affect electrochemical sulfate production.

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Electrolyte cations can have significant effects on the kinetics and selectivity of electrocatalytic reactions. We show an atypical mechanism through which electrolyte cations can impact electrocatalyst performance─direct incorporation of the cation into the oxide electrocatalyst lattice. We investigate the transformations of copper electrodes in alkaline electrochemistry through operando X-ray absorption spectroscopy in KOH and Ba(OH) electrolytes.

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Wastewater is an underleveraged resource; it contains pollutants that can be transformed into valuable high-purity products. Innovations in chemistry and chemical engineering will play critical roles in valorizing wastewater to remediate environmental pollution, provide equitable access to chemical resources and services, and secure critical materials from diminishing feedstock availability. This perspective envisions ─the use of electrochemical processes to tune and recover specific products from wastewaters─as the necessary framework to accelerate wastewater-based electrochemistry to widespread practice.

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The chlorine evolution reaction (CER) is a key reaction in electrochemical oxidation (EO) of water treatment. Conventional anodes based on platinum group metals can be prohibitively expensive, which hinders further application of EO systems. Crystalline cobalt antimonate (CoSbO) was recently identified as a promising alternative to conventional anodes due to its high catalytic activity and stability in acidic media.

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Ion exchange (IX) is a promising technology for selective nitrogen recovery from urine; however, IX requires chemical-intensive regeneration that escalates energy consumption and carbon emissions. To overcome this barrier, we demonstrated and investigated a novel electrified IX stripping process (EXS) enabling electrochemical IX regeneration with simultaneous ammonia stripping. EXS combines a weak acid cation exchange resin (WAC) to concentrate ammonia, a bipolar membrane to produce protons for WAC regeneration, and membrane stripping to recover the eluted ammonium from WAC.

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Treatment of domestic wastewater can recover valuable resources, including clean water, energy, and ammonia. Important metrics for these systems are greenhouse gas (GHG) emissions and embodied energy, both of which are location- and technology-dependent. Here, we determine the embodied energy and GHG emissions resulting from a conventional process train, and we compare them to a nonconventional process train.

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Wastewater-based epidemiology (WBE) has been widely deployed during the COVID-19 pandemic, but with limited evaluation of the utility of discrete sampling for large sewersheds and low COVID-19 incidence. In this study, SARS-CoV-2 RNA was measured in 72 consecutive hourly influent grab samples collected at a wastewater treatment plant serving nearly 500 000 residents when incidence was low (approximately 20 cases per 100 000). We characterized diurnal variability and relationships between SARS-CoV-2 RNA detection and physicochemical covariates [flow rate, total ammonia nitrogen (TAN), and total solids (TS)].

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The electrochemical nitrate reduction reaction (NORR) on titanium introduces significant surface reconstruction and forms titanium hydride (TiH, 0 < x ≤ 2). With grazing-incidence X-ray diffraction (GIXRD) and X-ray absorption spectroscopy (XAS), we demonstrated near-surface TiH enrichment with increasing NORR applied potential and duration. This quantitative relationship facilitated electrochemical treatment of Ti to form TiH/Ti electrodes for use in NORR, thereby decoupling hydride formation from NORR performance.

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Highly selective separation materials that recover total ammonia nitrogen (i.e., ammonia plus ammonium, or TAN) from wastewaters as a pure product can supplement energy-intensive ammonia production and incentivize pollution mitigation.

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By 2050, the societal needs and innovation drivers of the 21st century will be in full swing: mitigating climate change, minimizing anthropogenic effects on natural ecosystems, navigating scarcity of natural resources, and ensuring equitable access to quality of life will have matured from future needs to exigent realities. Water is one such natural resource, and will need to be treated and transported to maximize resource efficiency. In particular, wastewater will be mined for the valuable product precursors it contains, which will require highly selective separation processes capable of capturing specific target compounds from complex solutions.

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Capacitive deionization (CDI) devices use cyclical electrosorption on porous electrode surfaces to achieve water desalination. Process modeling and design of CDI systems requires accurate treatment of the coupling among input electrical forcing, input flow rates, and system responses including salt removal dynamics, water recovery, energy storage, and dissipation. Techno-economic analyses of CDI further require a method to calculate and compare between a produced commodity (e.

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Removal and recovery of phosphate from wastewater can minimize deleterious environmental impacts and supplement fertilizer supply. Hybrid anion exchangers (HAIX, with doped ferric oxide nanoparticles (FeOnp)) can remove phosphate from complex wastewaters and recover concentrated phosphate solutions. In this study, we integrate HAIX with a weak acid cation exchanger (WAC) to enrich phosphate and calcium in mild regenerants and precipitate both elements for recovery.

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Extracting valuable products from wastewaters with nitrogen-selective adsorbents can offset energy-intensive ammonia production, rebalance the nitrogen cycle, and incentivize environmental remediation. Separating nitrogen (N) as ammonium from other wastewater cations (e.g.

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Recovering nitrogen from wastewater can simultaneously fulfill the roles of traditional removal technologies such as nitrification-denitrification and fertilizer production processes such as Haber-Bosch. We have recently demonstrated a proof-of-concept for selective recovery of the fertilizer ammonium sulfate via electrochemical stripping, a combination of electrodialysis and membrane stripping. In this study, we furthered electrochemical stripping from concept to informed practice by investigating the effects of influent concentration (30, 300, and 3000 mg N/L), catholyte temperature (15, 23, and 35 °C), and gas permeable membrane choice on electrochemical nitrogen removal and recovery.

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Algal systems have emerged as a promising strategy for simultaneous treatment and valorization of wastewater. However, further advancement and real-world implementation are hindered by the limited knowledge on the full energetic and nutrient product potentials of such systems and the corresponding value of these products. In this work, an aqueous-based system for the conversion of wastewater-derived algae and upgrading of crude products was designed and demonstrated.

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Recovering nitrogen from separately collected urine can potentially reduce costs and energy of wastewater nitrogen removal and fertilizer production. Through benchtop experiments, we demonstrate the recovery of nitrogen from urine as ammonium sulfate using electrochemical stripping, a combination of electrodialysis and membrane stripping. Nitrogen was selectively recovered with 93% efficiency in batch experiments with real urine and required 30.

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Nitrogen standards for discharge of wastewater effluent into aquatic bodies are becoming more stringent, requiring some treatment plants to reduce effluent nitrogen concentrations. This study aimed to assess, from a life-cycle perspective, an innovative decentralized approach to nitrogen recovery: ion exchange of source-separated urine. We modeled an approach in which nitrogen from urine at individual buildings is sorbed onto resins, then transported by truck to regeneration and fertilizer production facilities.

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Separate collection of urine, which is only 1% of wastewater volume but contains the majority of nitrogen humans excrete, can potentially reduce the costs and energy input of wastewater treatment and facilitate recovery of nitrogen for beneficial use. Ion exchange was investigated for recovery of nitrogen as ammonium from urine for use as a fertilizer or disinfectant. Cation adsorption curves for four adsorbents (clinoptilolite, biochar, Dowex 50, and Dowex Mac 3) were compared in pure salt solutions, synthetic urine, and real stored urine.

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