A bioinspired iron catalyst for nitrate and perchlorate reduction

Abstract

Nitrate and perchlorate have considerable use in technology, synthetic materials, and agriculture; as a result, they have become pervasive water pollutants. Industrial strategies to chemically reduce these oxyanions often require the use of harsh conditions, but microorganisms can efficiently reduce them enzymatically. We developed an iron catalyst inspired by the active sites of nitrate reductase and (per)chlorate reductase enzymes. The catalyst features a secondary coordination sphere that aids in oxyanion deoxygenation. Upon reduction of the oxyanions, an iron(III)-oxo is formed, which in the presence of protons and electrons regenerates the catalyst and releases water.

Enzyme Mimetic Active Intermediates for Nitrate Reduction in Neutral Aqueous Media

“…Given the imbalances in the global nitrogen cycle associated with the overuse of nitrogen‐rich fertilizers and accumulation of toxic nitrate (NO 3 − ) in agricultural runoff, research in the field of nitrogen chemistry has focused on the design of efficient nitrate reduction reaction (NRR) catalysts However, because NO 3 − typically has low binding affinity and nucleophilicity on transition metals because of its planar symmetrical ( D 3 h ) resonant structure, the harsh reaction conditions, such as high temperature, UV‐light photolysis, or strongly acidic pH, are required to facilitate NO 3 − reduction …”

“…In contrast to artificial catalysts, nature has developed sophisticated and efficient machinery for catalyzing the NRR. For example, nitrate reductase (NRase) is the most efficient NRR catalyst in neutral aqueous solutions and selectively reduces NO 3 − to NO 2 − at about 150 mV vs. NHE (pH 6) at ambient temperature . All known naturally occurring NRases exclusively utilize Mo as the catalytic center and have similar structural configurations, in which a mononuclear Mo atom is coordinated by oxo and dithiolene sulfur ligands connected to one or two pterin groups (Scheme ).…”

OsNLP4is required for nitrate assimilation gene expressions and nitrate-dependent growth in rice

“…In the aforementioned RNA-seq result, MOT1 and IRT1 mRNA accumulations were reduced in the osnlp4-1 (Supplemental Figure S3C). Molybdenum and iron have been reported to be essential for the activity of nitrate reductase through covalently bounding to specific domains of the enzyme (Liu et al, 2017b, Ford et al, 2016). We checked the mRNA expression levels of MOT1 , IRT1 and IRT2 in root via qRT-PCR.…”

Pd0‐ and Au0‐Nanoparticles Catalyze the Reduction of Perchlorate by ·C(CH3)2OH Radicals

“…Perchlorate is currently used as a fuel in missiles, explosives, fireworks, and pyrotechnics, and its leakage into aquatic media is of environmental concern The main environmental problem is due to the behavior of perchlorate as a source of biological harm; for example, the intake of perchlorate by the thyroid, thus inhibiting the production of the thyroid hormone , . Perchlorate is very stable in aqueous solutions and has high mobility in the environment .…”

“…Perchlorate is very stable in aqueous solutions and has high mobility in the environment . Therefore, the chemical reduction of perchlorate often requires the use of harsh conditions . The sources of the stability of perchlorate are the following redox potentials:…”