En el presente trabajo se ha investigado la biosorción de Cu (II) por las biomasas pretratadas de cáscara de citrus sinensis (naranja), citrus limonium, (limón) y opuntia ficus (palmeta de nopal). Las biomasas fueron tratadas con cloruro de calcio, el cual les da una mayor estabilidad mecánica al material bioadsorbente. Los experimentos sobre el efecto del pH en el proceso de biosorción de Cu (II) por los materiales biosorbentes mostraron que el rango óptimo de pH se encuentra entre 4,5 - 5,0. Los datos experimentales obtenidos se procesaron usando las ecuaciones adsorción de Langmuir y Freundlich. La máxima capacidad de biosorción de Cu (II) por las biomasas fueron: 36,1011 mg/g para la cáscara de citrus sinensis; 47,0436 mg/g para cáscara de citrus limonium y 44,2567 mg/g para el opuntia ficus.

The novel compound 3-nitro-N-(1, 1, 3-trioxo-1, 3-dihydro-2H-1λ6, 2-benzothiazole-2- carbothioyl)benzamide has been synthesized and is characterized by elemental analysis, infrared spectroscopy, nuclear magnetic resonance 1H and 13C. The structure of the new compound shows a characteristic signal in the 1H-NMR spectrum of the NH group to fields highly displaced by the presence of a highly deprotected hydrogen at 11.90 ppm, due to the existence of a hydrogen bond between the C = O of saccharin group and the NH group.

The coordination compound saccharinatecopper(I), [Cu2(C7H4SO3N)2]n, was obtained by reduction reaction of copper sulfate with ascorbic acid and addition of sodium saccharinate in aqueous medium. The characterization was performed by elemental analysis, X ray photoelectron spectroscopy, infrared spectrophotometry and cyclic voltammetry.

The objective of the present work was to determine the optimal conditions for the coagulation of suspended particles of silver iodide of negative charge by the action of solutions of chitosan, aluminum sulfate and the mixed action of both coagulants. The suspension of colloidal particles of AgI was obtained by mixing diluted solutions of KI and AgNO3 in excess of KI. In all the experiments the volume of the colloidal system was 600 mL and pH= 6. The optimal parameters for the coagulation process were determined based on the Jar Test method. For the chitosan solution the optimal parameters were: concentration 0.01%, pH = 4.5 and a volume of 25 mL; for aluminum sulfate: concentration 30 ppm, pH = 4.0 and volume 25 mL. In the case of the mixed action of both coagulants, the optimal parameters were 5 mL of a 30 ppm solution of aluminum sulfate at pH 4.0 and 20 mL of a 0.01% chitosan solution...