ABSTRACT
Recent developments in wastewater treatment have led to a renewed interest to obtain elemental sulphur (S°) as a by-product from bioreactors. However, practical studies are limited by the gap of adequate analytical techniques for its determination. This paper provides a statistical study and matrix effect evaluation of an adapted spectrophotometric method for routine S° analyses in aqueous samples, based on a methodology previously described by Hart (1961). Four complex matrices were tested: domestic sewage and effluent samples from three different bioreactors. Tested performance criteria included linearity, matrix effect, limit of detection and quantification and S° recovery. Results were linear (R2 = 0.99994) in the studied range (5 to 100 mg S° L−1) and no matrix effect was observed. The accuracy was based on recovery values that varied from 100% to 106%. The colloidal S° separation and extraction protocol was also considered suitable for aqueous samples, reaching more than 99.0% of S° recovery.
Acknowledgments
This study was financially supported by the São Paulo Research Foundation (FAPESP) – grant numbers 2015/18976-0 and 2015/06246-7, the National Council for Scientific and Technological Development (CNPq) – process number 141906/2014-6, and the Coordination for the Improvement of Higher Education Personnel (CAPES).
Disclosure statement
No potential conflict of interest was reported by the authors.