In this work, a batch adsorption study was conducted to investigate the removal efficiency of lead, copper and zinc ions from aqueous solutions. Magnetic amine-functionalized mesoporous silica nanoparticles were synthesized by grafting amine groups within the channels of magnetic mesoporous silica nanocomposites. Morphological and structural characterizations were made by X-ray powder diffraction, N2 adsorption-desorption, scanning and transmission electron microscopy, Fourier transform infrared spectroscopy and elemental analysis. Among different factors influencing the sorption process, solution pH, shaking time and mass of adsorbent were investigated. The removal efficiencies were higher than 98% under optimized experimental conditions. Maximum adsorption capacities calculated by the Langmuir model were 268, 93 and 82 mg g-1, for lead(II), copper(II) and zinc(II) ions, respectively. Accuracy and applicability of the synthesized adsorbent was estimated by analyzing spiked natural water samples and good recoveries (> 95%) were obtained with no matrix interferences.

Neste trabalho, o papel de filtro quimicamente modificado com polianilina/polipirrol (PANI/PPY), denominado de nanocompósito PANI/PPY/celulose, foi preparado e usado como sorvente para extração em fase sólida (SPE) para a pré-concentração e extração de alguns pesticidas organoclorados (OCPs) em amostras de águas naturais. O sorvente proposto também foi caracterizado por microscopia eletrônica de varredura (SEM), que mostrou que polímeros globulares poderiam ser incorporados pelas fibras de celulose da folha de papel. Vários parâmetros experimentais relacionados à pré-concentração de OCPs no papel de filtro recoberto também foram examinados. Os resultados experimentais mostraram que o papel de filtro recoberto por PANI/PPY poderia extrair OCPs com fatores de enriquecimento relativamente altos. A avaliação também exibiu um intervalo dinâmico dos OCPs de 5-250 µg L-1 com um coeficiente de correlação (R²) apropriado. Os limites de detecção de heptacloro, aldrin, dieldrin, endrin e 4-diclorodifeniltricloroetano (4-DDT) foram determinados como sendo 0,39, 0,28, 0,47, 0,51 e 0,31 µg L-1, respectivamente. O método proposto também foi aplicado na análise de OCPs em amostra de água do mar e as recuperações dos analitos foram na faixa de 77,4 a 102,7%.

In this work, the chemically modified filter paper with polyaniline/polypyrrole (PANI/PPY), denoted as PANI/PPY/cellulose nanocomposite, was prepared and used as the solid phase extraction (SPE) sorbent for preconcentration and extraction of some organochlorine pesticides (OCPs) in natural water samples. The proposed sorbent was also characterized with scanning electron microscopy (SEM) and exhibited that globular polymers could incorporate into the cellulose fibers of the paper sheet. Several experimental parameters related to the preconcentration of OCPs on the coated filter paper were also examined. The experimental results showed that the PANI/PPY coated filter paper could extract OCPs with relatively high enrichment factors. The evaluation also exhibited a dynamic range of 5-250 µg L-1 for OCPs with proper correlation coefficient (R²). The limit of detections of heptachlor, aldrin, dieldrin, endrin and 4-dichlorodiphenyltrichloroethane (4-DDT) were found to be 0.39, 0.28, 0.47, 0.51 and 0.31 µg L-1, respectively. The proposed method was also applied for analysis of OCPs in seawater sample and the recoveries of analytes were in the range of 77.4 to 102.7 %.

Neste trabalho, bifenila e óxido de bifenila foram extraídos por microextração em headspace com única gota (HS-SDME) e analisados por cromatografia gasosa com detector de ionização em chama (GC-FID). A extração ocorreu a partir da ponta de uma microsseringa, pela suspensão de uma gota de tolueno, de 3,5 µL, como solvente extrator, contendo acetonaftona como padrão interno. O efeito de diferentes parâmetros como a natureza do solvente de extração, temperaturas da amostra e da microgota, velocidade de agitação, volumes da amostra e da microgota, força iônica e tempo de extração na eficiência da extração dos analitos foram investigados e otimizados. Sob condições ótimas, os limites de detecção (S/N = 3) da bifenila e óxido de bifenila foram 0,40 ± 0,03 e 0,30 ± 0,06 µg mL-1, respectivamente. Boas linearidades foram obtidas para ambos analitos com os coeficientes de correlação superiores a 0,997 e desvios-padrão relativos (R.S.D.) de 1 a 3%. As recuperações dos analitos a partir das amostras de água enriquecida foram próximas a 100%.

In this work, biphenyl and biphenyl oxide were extracted by headspace single drop microextraction (HS-SDME) and analyzed by gas chromatography-flame ionization detection (GC-FID). The extraction occurred from the tip of a microsyringe by suspending a 3.5 µL drop of toluene, as extracting solvent, containing acetonaphton, as internal standard. The effect of different parameters such as the nature of extraction solvent, microdrop and sample temperatures, stirring rate, microdrop and sample volumes, ionic strength and extracting time on the extraction efficiency of the analytes were investigated and optimized. Under optimized conditions the limits of detection (S/N = 3) of biphenyl and biphenyl oxide were 0.40 ± 0.03 and 0.30 ± 0.06 µg mL‑1, respectively. Good linearities were obtained for both analytes with the correlation coefficients higher than 0.997 and the relative standard deviations (R.S.D.) were in the range of 1-3%. The recoveries of analytes from spiked water samples were near to 100%.