Multivariate optimization of pressurized solvent extraction of alkylphenols and alkylphenol ethoxylates from biosolids

Abstract

Neste estudo, uma metodologia de extração em solvente pressurizado de alquilfenóis (APs) e alquilfenóis etoxilados (APEOs) a partir de biosólidos foi otimizada utilizando-se um biosólido contendo nativamente estes compostos em um nível de concentração elevada. A otimização da extração foi realizada através de um planejamento experimental de análise multivariada com um planejamento composto central (CCD) produzindo os seguintes valores otimizados: temperatura de 129 o C, tempo de extração por ciclo de 34 min em dois ciclos e acetona como solvente de extração. Em comparação com a extração Soxhlet, esta metodologia acabou por ser mais eficiente para a extração de APEOs e de eficiência semelhante para a extração de APs. Por outro lado, a metodologia é consideravelmente mais rápida do que a de Soxhlet e usa uma pequena quantidade de solvente de extração. As concentrações de 204 ± 20 e 1053 ± 23 mg kg -1 de nonilfenol e nonilfenol-etoxilato, respectivamente, foram determinadas na amostras de biosólido.In this study, a methodology for pressurized solvent extraction of alkylphenols (APs) and alkylphenol ethoxylates (APEOs) from biosolids was optimized by utilizing a biosolid natively containing these compounds at a high concentration level. Optimization of the extraction was carried out through a multivariate analysis experimental design with a central composite design (CCD) producing the following optimum values for the variables: temperature of 129 ºC, extraction time per cycle of 34 min in two cycles and acetone as extraction solvent. Upon comparison with Soxhlet extraction, this methodology turned out to be more efficient for the extraction of APEOs and of similar efficiency for APs. On the other hand, the methodology is considerably faster than Soxhlet and uses a smaller amount of extraction solvent. Concentrations of 204 ± 20 and 1053 ± 23 mg kg -1 for nonylphenol and nonylphenol-ethoxylate, respectively, were determined in the biosolid sample assayed.

Comparison of Ethyl Acetate with Hexane for Oil Extraction from Various Oilseeds

“…Under this condition, the ethyl acetate would be in a subcritical state since the working pressure (1500 psi) was above the critical pressure of that solvent (557.0 psi). Therefore, ethyl acetate would have a smaller dielectric constant and, hence, its polarity would also be decreased [46,47]. It may be possible to determine the dielectric constant of ethyl acetate that decreases considerably, from 6.02 under normal conditions to 3.19 under these extraction conditions [48,49].…”

Extraction Techniques for Isolation, Purification and Preconcentration of Bisphenols and Alkylphenols from Environmental and Food Samples

“…For this purpose the most often used methods are liquid-liquid extraction [20][21][22], Soxhlet extraction [3,23], solid phase extraction [6,22,, membrane extraction [45][46][47], accelerated solvent extraction [7,13,[48][49][50][51][52][53][54], ultrasonic assisted extraction [32,[55][56][57][58], microwave assisted extraction [59][60][61], stir-bar sorptive extraction [4,[62][63][64][65][66][67][68][69], matrix solid phase dispersion [70][71][72][73][74] …”

“…The clean-up step was carried out in glass columns filled with aluminium oxide. The detected concentration of all analytes was between1.2-1053 mg/kg [51]. Selective PLE was applied for the simultaneous isolation of BPA and alkylphenols (4-tert-butylphenol, 4-nbutylphenol,4-n-pentylphenol,4-n-hexylphenol, 4-n-heptylphenol, 4-n-octylphenol, 4-tert-octylphenol, 4-n-nonylphenol) from sewage sludge samples.…”

“…Solid phase extraction using various kinds of cartridges (Oasis HLB, C18 silica, amino propyl silica, aluminum oxide, Florosil) are often applied for clean-up extracts which were obtained after varied extraction techniques: liquid-liquid extraction [21,22], Soxhlet extraction [3], pressurized solvent extraction [7,13,49,51], ultrasound assisted extraction [56,58], microwave assisted extraction [59,60] and matrix solid phase dispersion [74].…”

Optimization of Acid Hydrolysis of Myricetin-3-O-rhamnoside Using Response Surface Methodology

“…D values can vary from 0 to 1 and usually have a directly proportional relationship with the dependent variable in experiments that aim to maximize the product. 22,23 Thus, the optimized conditions for the HCl concentration, temperature and reaction time would be those in which the D value corresponds to the maximization of the concentration of aglycones produced (reaction yield), i.e., D = 1. For validation, hydrolysis was performed in triplicate under the optimum conditions.…”