Use of Doehlert and constrained mixture designs in the development of a photo-oxidation procedure using UV radiation/H2O2 for decomposition of landfill leachate samples and determination of metals by flame atomic absorption spectrometry

Abstract

This work proposes the use of photo-oxidation degradation with UV radiation/H 2 O 2 as sample treatment for the determination of Fe, Zn, Mn, Ni and Co in municipal solid waste landfill leachate by flame atomic absorption spectrometry (FAAS). Three variables (pH, irradiation time and buffer concentration) were optimized using Doehlert design and the proportions of mixture components submitted to UV radiation (leachate sample, buffer solution and H 2 O 2 30%, v/v) were optimized using a constrained mixture design. Using the experimental conditions established, this procedure allows limits of detection of 0.075, 0.025, 0.010, 0.075 and 0.041 µg mL -1 , and the precision levels expressed as relative standard (%RSD, 0.5 µg mL -1 ) were 3.6, 1.8, 1.3, 3.3 and 1.7%, for Fe, Mn, Zn, Ni and Co respectively. Recovery tests were carried out for evaluation of the procedure accuracy and recoveries were between 92 and 106% for the studied metals. This procedure has been applied for the analysis of the landfill leachate collected in Jequié, a city of the southwestern region of the State of Bahia, Brazil. The results were compared with those obtained by acid digestion. There was no significant difference between the results obtained by the two methods based on paired t-test at 95% confidence level.

Optimization of Analytical Methods Using Response Surface Methodology - Part II: Mixture Variables

“…Bezerra et al 59 A superfície obtida apresentou um ponto de sela e a análise de variância mostrou que o modelo quadrático ajustado não apresenta falta de ajuste (p = 0,4488 > 0,05…”

Leachate and vinasse used in a biological process combined with Fenton’s reaction: a green method for treatment of textile effluents

“…As a source of microorganisms for the biological treatments, an interesting alternative would be leachate, a dark and viscous liquid produced in the biodegradation of solid and pasty organic residues, considered to be an environmental pollutant and found mainly in landfills. If not adequately treated, it may cause severe environmental impacts primarily through the contamination of water tables (Bezerra et al 2015, Yao 2017.…”