DON is ubiquitously present in the environment. Its spatial and temporal variations are sometimes indicative of the influence of microbial activity, anthropogenic influence, or certain photo-mineralization processes. Recent concerns of DON have been extended to environmental issues, such as the formation of nitrogenous disinfection byproducts, membrane fouling, eutrophication, and nitrification of distribution system. Therefore, a better understanding of the occurrence and control of DON becomes important. This study evaluates the feasibility of electrodialysis (ED) as a pretreatment method to enable direct analysis of DON in water. The primary goal is to separate dissolved inorganic nitrogen (DIN) species from DON completely, so that DON can be equated to total dissolved nitrogen (TDN). Within three hours, the ED cell achieved > 99% removals of three DIN species (i.e., ammonia, nitrite, and nitrate) and meanwhile > 80 % recoveries of an array of standard DON compounds, including amino acids, peptide, protein, and humic substances. In general, small molecular weight (MW) compounds showed higher DON recovery than high MW compounds, suggesting that the losses of DON during ED pretreatment were mainly attributed to adsorption effect rather than permeation. For a matrix of samples with varying ratios of DIN to DON, the DON data with ED pretreatment exhibited remarkable higher accuracy and precision than those without pretreatment. In addition, little changes were observed on the ultraviolet and visible spectra of samples after ED pretreatment, indicating that the ED process has resulted in little alternation of organic matter characteristics. A survey of natural and engineering water samples further confirmed the benefits of using ED pretreatment.

Application of electrodialysis pretreatment to enable direct analysis of dissolved organic nitrogen (DON) in water

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.