Development of flow injection potentiometric methods for the off-line and on-li...

• Author(s): Mesquita, Raquel B. R. ; Santos, Inês C. ; Pedrosa, Marta F. F. ; Duque, Anouk ; Castro, Paula M. L. ; Rangel, António O. S. S.
• Date: 2011
• Persistent ID: http://hdl.handle.net/10400.14/7463
• Origin: Veritati - Repositório Institucional da Universidade Católica Portuguesa
• Subject(s): Flow injection analysis; Potentiometric fluoride determination; Online; Monofluorophenol
• Document Type: Article
• Language: English

Description

Water treatment has become a source of concern as new pollutants and higher volumes of waste water must be treated. Emerging biological approaches, namely the use of bioreactors, for cleaning processes have been introduced. The use of bioreactors requires the development of efficient monitoring tools, preferably with realtime measurements. In this work, a couple of flow injection systems were developed and optimized for the potentiometric determination of fluoride to monitor a rotating biological contactor (RBC) bioreactor and a sequencing batch reactor (SBR) with offline and online sampling. Both the RBC and the SBR bioreactors were set up for the biodegradation of the halogenated organic compound 2fluorophenol and, as fluoride was a degradation byproduct, the process was monitored by following up its concentration. The described flow injection potentiometric methods enabled the fluoride determination within the required quantification range 0.10–100mM. The possible interferences from the growth medium were minimized inline. The determination rate was 78 h−1 for the offline monitoring of RBC and 50−1 h for the online monitoring of the SBR, with a sample consumption of 0.500mL and 0.133mL per determination, respectively. Furthermore, the overall reagent consumption was quite low. The accuracy of the system was evaluated by comparison with a batch procedure. The SBR efficiency was monitored both online by the flow system and offline by HPLC, for comparison purposes.