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R A Minear

Publications and source records attributed to R A Minear.

6 recordsLinked to original sources
PubMed2006

Kinetics of the reaction of hypobromous acid and organic matters in water treatment processes.

The fate of bromine species from human activity is affected by the bromination reaction in water treatment processes. In this study, kinetic information of the reaction between hypobromous acid (HOBr) and seven different natural organic matters (NOM) was collected by sequential stopped-flow techniques. Multiple reaction phases were found in the reaction between HOBr and NOM. The number of reaction sites for the faster reaction phase ranged from 0.26 to 0.92 micromole (mg DOC)(-1), and was correlated to both SUVA and specific phenolic content at pH 7.0. The apparent second-order rate constants for the faster reaction phase at pH 7.0 ranged from 5.4 x 10(5) to 1.4 x 10(6) M(-1) x s(-1), indicating that vanillin-like structures are involved in this reaction phase.

Benzaldehydes↗
PubMed2001

Comparison of three post-column reaction methods for the analysis of bromate and nitrite in drinking water.

Three post-column ion chromatographic methods (i.e., a sodium bromide-sodium nitrite method, an o-dianisidine method, and a potassium iodide-ammonium heptamolybdate method) were compared for bromate and nitrite analysis. Also, the effect of direct mixing of the reagents without ion suppressors for the sodium bromide-sodium nitrite method and the potassium iodide-ammonium heptamolybdate method was investigated. For the analysis of bromate, the three methods showed similar method detection limits (0.17-0.24 microg/l) with pneumatic reagent delivery systems. Direct reagent mixing achieved comparable detection limits to the suppressor configuration. The three methods are also compatible with conductivity detection. When used in combination with conductivity detection, this compatibility allows simultaneous analysis of bromate, nitrite, and other common ions in drinking water, such as bromide. It was found that the o-dianisidine method achieves microg/l-level detection of nitrite and bromate with a simpler configuration than the potassium iodide-ammonium heptamolybdate method, while the sodium bromide-sodium nitrite method was not sufficiently sensitive for nitrite analysis at the microg/l level.

Bromates↗
PubMed2001

Evaluation of the treatment performance of a multistage ozone/hydrogen peroxide process by decomposition by-products.

The performance of a multistage ozone/hydrogen peroxide (O3/H2O2) process was evaluated with respect to total organic carbon (TOC) removal of waste waters. An aqueous humic acid solution (5.2 mgC l(-1) as TOC) and a sand filtered secondary sewerage effluent (5.6mgC l(-1) as TOC) were used as model waste waters. Appropriate range of hydrogen peroxide (H2O2) dose at each stage depended upon the components of the tested solutions that changed as the process proceeded. Higher hydrogen peroxide dose was required at later stages in which low reactivity compounds with hydroxyl radical (HO*), low molecular fatty acids, were predominant. And, oxalic acid concentration related to H2O2 demand at later stages. This was assumed that the slow decomposition of oxalic acid was rate-determining step for TOC removal after its accumulation. Also, it is important to maintain dissolved ozone at low concentration for efficient TOC removal because rapid ozone consumption is required for the rapid formation of hydroxyl radical (HO*).

Carbon↗
PubMed1974

Organics.

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Carbamates↗