Table of Contents
Advances in Environmental Chemistry
Volume 2016 (2016), Article ID 3468635, 10 pages
http://dx.doi.org/10.1155/2016/3468635
Research Article

Determination of Hexavalent Chromium (Cr(VI)) Concentrations via Ion Chromatography and UV-Vis Spectrophotometry in Samples Collected from Nacogdoches Wastewater Treatment Plant, East Texas (USA)

Department of Chemistry & Biochemistry, Stephen F. Austin State University, Box 13006, SFA Station, Nacogdoches, TX 75962-13006, USA

Received 19 October 2015; Revised 25 January 2016; Accepted 27 January 2016

Academic Editor: Claire Richard

Copyright © 2016 Kefa K. Onchoke and Salomey A. Sasu. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The concentration of hexavalent chromium (Cr(VI)), a toxic environmental pollutant and carcinogen, was determined in samples collected from Nacogdoches Wastewater Treatment Plant (NWWTP) using ion chromatography and UV-visible spectrophotometry (IC, UV-Vis). On reaction with 1,5-diphenylcarbazide (DPC) Cr+6 forms a 1,5-diphenylcarbazide-Cr(VI) complex, which is then analyzed at 530 nm and 540 nm, respectively. Via ion chromatography Cr(VI) concentrations were in the range of and  ppm at the influent and effluent, respectively. With the use of standard addition wastewater samples were spiked with a 0.5 ppm Cr(VI) standard of various amounts and subsequently analyzed with UV-Vis spectrophotometry. The spiked concentrations gave Cr(VI) concentrations in the range of  ppm and  ppm at the influent and influent wastewater, respectively. The determined Cr(VI) concentrations through the ion chromatography and UV-Vis spectrophotometry are below the maximum USEPA contaminant concentration of 0.1 ppm. From the analysis, the NWWTP efficiently removes Cr(VI) before discharge into the environment through La Nana Creek. The removal efficiency for Cr(VI) was determined to be ≥92.8% along the wastewater treatment stages from the influent (aeration stage) to the effluent stages prior to discharge into the La Nana Creek.