Effect of the surfactant benzalkonium chloride in the sorption of paraquat and cadmium on montmorillonite

Pesticides, heavy metals and surfactants can share the same region or site in the environment and thus they may compete for the surface of minerals. A competitive study of the adsorption between the cationic surfactant benzalkonium chloride (BAC) with the heavy metal cadmium (Cd(II)) and the cationic herbicide paraquat (PQ) on montmorillonite is presented. Adsorption isotherms for BAC, PQ and Cd(II) were performed in single solute systems and also in binary solute systems, PQ+BAC and Cd(II)+BAC to evaluate the effects of BAC on the adsorption of the other two substances. The affinities of BAC and PQ were strong and similar, thus BAC affected significantly the adsorption of PQ and vice versa. The affinity of Cd(II) for the montmorillonite surface was low, thus BAC affected appreciably Cd(II) adsorption, but the heavy metal did not modify BAC adsorption. XRD data show that BAC molecules control the magnitude of the basal spacing.Fil: Ilari, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Etcheverry, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Zenobi, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Zanini, Graciela Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentin

Identification of 17 novel mutations in 40 Argentinean unrelated families with mucopolysaccharidosis type II (Hunter syndrome)

Mucopolysaccharidosis type II (MPSII) is an X-linked lysosomal storage disorder caused by deficiency of the enzyme iduronate-2-sulfatase (IDS). The human IDS gene is located in chromosome Xq28. This is the first report of genotype and phenotype characterization of 49 Hunter patients from40 families of Argentina. Thirty different alleles have been identified, and 57%were novel. The frequency of de novomutationswas 10%. Overall, the percentage of private mutations in our series was 75%.Facultad de Ciencias Exacta

Identification of 17 novel mutations in 40 Argentinean unrelated families with mucopolysaccharidosis type II (Hunter syndrome)

Mucopolysaccharidosis type II (MPSII) is an X-linked lysosomal storage disorder caused by deficiency of the enzyme iduronate-2-sulfatase (IDS). The human IDS gene is located in chromosome Xq28. This is the first report of genotype and phenotype characterization of 49 Hunter patients from40 families of Argentina. Thirty different alleles have been identified, and 57%were novel. The frequency of de novomutationswas 10%. Overall, the percentage of private mutations in our series was 75%.Facultad de Ciencias Exacta

A simple cation exchange model to assess the competitive adsorption between the herbicide paraquat and the biocide benzalkonium chloride on montmorillonite

Since adsorption on clay minerals is one of the most popular water-pollutant removal method, it is important to consider the coexistence of several compounds that can affect pollutant retention. In this work, the competitive behaviour between cationic herbicide paraquat (PQ) and a benzalkonium chloride compound (BAC) on montmorillonite (MMT) was performed by adsorption experiments and analysed by a theoretical cation exchange model. Experimental studies included adsorption isotherms, XRD, FTIR and zeta potential (ζ). Binary systems (BAC + PQ) were performed at different initial concentrations ratio BAC/PQ = 0.1; 0.5; 1.0; 2.0 and 3.0. Results showed that at higher BAC initial concentration, the maximum adsorbed PQ amount decreases. X-Ray diffractograms showed that as the BAC/PQ ratio increases, the MMT basal spacing peak shifts to lower angles suggesting that the basal spacing is mainly controlled by the presence of BAC. Besides, the total adsorbed amount (adsorbed PQ plus adsorbed BAC) is closer to clay CEC value (0.91 mEq g−1), at this value ζ ≅ 0 mV suggesting that the adsorption occurs through a cation exchange mechanism. The theoretical model applied was originally developed to describe the exchange of simple cations on clay minerals, however it was effective in predicting the behaviour of larger cations such as PQ and BAC. In this scenario, thermodynamic parameters calculated through the model indicate that cation exchange process is spontaneous towards adsorbed BAC, suggesting that an adsorbed PQ cation is replaced by an equivalent amount of BAC cation (expressed in terms of electrical charge).Fil: Ilari, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Etcheverry, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Waiman, Carolina Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Zanini, Graciela Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentin

Fluorescence enhancement novel green analytical method for paraquat herbicide quantification based on immobilization on clay

A new green method was developed for the quantification of paraquat (PQ) in water samples based on the fluorescence emission enhancement of the herbicide signal after adsorption on sodium montmorillonite clay (MMT). Radiant emission processes are favored by increasing the molecular rigidity of the PQ since it adopts a planar position between the nano-sheets of the MMT. The advantages of the use of this clay are nontoxic, low cost and found in abundance in natural reserves. The proposed method was successfully used in determining PQ in natural water samples with recoveries of 73% to 95%. The fluorescence emission showed a good linear relationship with PQ concentrations from 2.0 to 8.0 μmol L-1 with a detection limit of 0.37 μmol L-1. The method is simple, inexpensive and does not require the use of reagents or organic solvents; which makes it very promising to achieve the goals of green chemistry. The proposed methodology could be the beginning of the development of future green sensors.Fil: Dominguez, Marina Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Insausti, Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Ilari, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Zanini, Graciela Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentin