The effects of natural organic matter (NOM), ferrozine, and AQDS (anthraquinone-2,6-disulfonate) on the reduction of hematite (alpha-Fe2O3) by Shewanella putrefaciens CN32 were studied. It has been proposed that NOM enhances the reduction of Fe(III) by means of electron shuttling or by Fe(II) complexation. Previously both mechanisms were studied separately using "functional analogues" (AQDS for...

Natural organic matter (NOM) is ubiquitous and is one of the most complex naturally occurring mixtures. NOM plays an essential role in the global carbon cycle; atmospheric and natural water photochemistry; and the long-range transport of trace compounds and contaminants. There is a dearth of separation techniques capable of resolving this highly complex mixture. To our knowledge, this is the fi...

This study investigates the aqueous stability of multi-walled carbon nanotubes (MWNTs) in the presence of natural organic matter (NOM). MWNTs were readily dispersed as an aqueous suspension in both model NOM (Suwannee River NOM (SR-NOM)) solutions and natural surface water (actual Suwannee River water with unaltered NOM background), which remained stable for over 1 month. Microscopic analyses s...

Biophysico-Chemical Processes Involving Natural Nonliving Organic Matter in Environmental Systems, Edited by Nicola Senesi, Baoshan Xing, and Pan Ming Huang Copyright © 2009 John Wiley & Sons, Inc. 17.

The characterisation and treatment of natural organic matter are becoming more important to the water utilities in the UK and around the world. This paper looks at the relationship between bulk and fractionated organic material and the performance of conventional water treatment processes.

Excited triplet states of aromatic ketones and quinones are used as proxies to assess the reactivity of excited triplet states of the dissolved organic matter ((3)DOM*) in natural waters. (3)DOM* are crucial transients in environmental photochemistry responsible for contaminant transformation, production of reactive oxygen species, and potentially photobleaching of DOM. In recent photochemical ...

Contaminant sorption, an important process that may limit bioavailability, hinder remediation, encourage environmental persistence, and control mobility in the environment, has been the focus of numerous studies. Despite these efforts, the fundamental understanding of sorptive processes in soil and sedimentary environments has not been resolved. For instance, many have suggested that contaminan...

Uranium is an important carbon-free fuel source and environmental contaminant that accumulates in the tetravalent state, U(IV), in anoxic sediments, such as ore deposits, marine basins, and contaminated aquifers. However, little is known about the speciation of U(IV) in low-temperature geochemical environments, inhibiting the development of a conceptual model of U behavior. Until recently, U(IV...

Humic acids (HA) are ubiquitous redox-active compounds of natural aquatic and soil systems. Here we studied the potential of HA as reductants for chlorinated aliphatic pollutants. To avoid artifacts potentially involved when studying chemically reduced HA, we prepared electrochemically reduced soil, aquatic and synthetic HA, and anthrahydroquinone-2,6-disulfonic acid (AHQDS), a model compound f...