Claudia Gutiérrez

Adsorption of copper onto agriculture waste materials.

Mining activities generate large amounts of wastewater, which contain heavy metals of elevated concentration according to legislative threshold values. Therefore, treatment is necessary, and there has been a recent focus on more environmentally friendly methods. One of these is biosorption, where heavy metals are adsorbed from the wastewater via materials of biological origin. In this work copper sorption capacity, kinetics and isotherms of different low-cost residual agricultural materials was studied. Seven different materials were investigated: peanut shells, nut shells, plum seeds, eucalyptus bark, olive pips, peach stones, and pine sawdust. The best sorption results were obtained in acidic pH for olive pips, peach stones and pine sawdust. Furthermore, it was observed that at higher pH, a longer duration of time is required before equilibrium is established. In general, the better biosorbents were found to be peach stones and pine sawdust with a sorption capacity at acidic pH around 10-15 mgCu g(-1) biosorbent. In addition it was found, that the Ho and McKay second order model described the sorption kinetics very satisfactorily. Both Langmuir and Freundlich models described the equilibrium sorption isotherms well for the biosorbents studied - with the last model being slightly better.

Biosorption of cadmium with brown macroalgae.

Sorption experiments for cadmium removal using two brown macroalgae Lessonia nigrescens and Durvillaea antarctica were carried out. Although both types of algae were capable of retaining cadmium, differences in their performance were observed. The optimum pH was 3.7±0.2, and to achieve the equilibrium, 5 days of contact time were necessary for both biosorbents. The maximum experimental uptake obtained was similar for the two biosorbents: 95.3 mg Cd g(-1) by D. antarctica and 109.5 mg Cd g(-1) by L. nigrescens. The Langmuir model described the equilibrium sorption isotherms very well for both biosorbents and the Lagergren pseudo primer order model described the sorption kinetics for L. nigrescens satisfactorily and the Ho and Mckay pseudo second order model for D. antarctica. It was found that cadmium uptake by D. antarctica was faster than by L. nigrescens.

Electrochemical Generation of Fenton's Reagent to Treat Spent Caustic Wastewater

Abstract This work shows the results of four Electro-Fenton laboratory tests to reduce the chemical oxygen demand in spent caustic solutions. The treatment consisted of i) a pH reduction followed by ii) an Electro-Fenton process, which was analyzed in this work. The efficiency of the Electro-Fenton process was analyzed as the COD reduction in pure phenol and sulphide solutions and real spent caustic samples. Close to 97% COD removal was achieved for sulphide treatment, and around 81% for phenol treatment. In the real spent caustic sample, 93% COD reduction was obtained. The sulphide content is lowered by both a pH reduction and the Electro-Fenton process, whereas the phenol concentration is not affected by the pH reduction – only by the Electro Fenton process.

Selenium removal from petroleum refinery wastewater using an electrocoagulation technique

In the present work, an electrocoagulation technique was tested as a possible technological alternative for the treatment of selenium in wastewater from a petroleum refinery. For this purpose, a batch airlift reactor with air stirring was used. The sacrificial electrodes were made of iron to generate the necessary ferrous ions for the process. The results indicated a selenium removal of 90% from the wastewater after 6 h of treatment, achieving a decrease in concentration from 0.30 mg L-1 to 0.03 mg L-1. The current density was found to be an important variable for the process. In conclusion, the electrocoagulation process seems to be a feasible selenium removal technique applied to petroleum refinery wastewater.

Medidas de autocuidado y genotipificación del virus papiloma humano en mujeres de la Unidad de Patología Cervical, Hospital Carlos Van Buren

Objetivo: Identificar las caracteristicas biosociales, medidas de autocuidado y genotipoficacion del virus papiloma humano en mujeres con papanicolaou alterado en la primera consulta de la Unidad Patologia Cervical, Hospital Carlos Van Buren, Valparaiso, 2013. Material y metodo: Cuantitativo, descriptivo y transversal. Aprobada por Comite Etico-Cientifico. Muestra de 50 mujeres que previa firma de consentimiento informado, se les aplico un cuestionario y se les tomo muestras cervicales para genotipificacion VPH con tecnica PCR e Hibridacion. Resultados: 26% con edad entre 25-34 anos, 58% tiene a lo menos cuarto medio, 66% tuvieron primera relacion sexual entre los 15-19 anos, 48% presentaron test positivos para VPH alto riesgo, 26% tiene antecedentes de otras infecciones de transmision sexual, 26% no se realiza el Pap de forma regular y 90% no utiliza preservativo. Discusion: Conocer algunas caracteristicas biosociales de la poblacion permite examinar estrategias gubernamentales en la prevencion de la adquisicion del VPH y por ende del desarrollo de cancer cervicouterino, como son: educacion sexual, estilos de vida saludables, estrategias para adhesion a la toma del Pap, entre otras. Ademas se hace necesario ampliar estudios e investigaciones en estos temas que permitan contribuir en la vida sexual de la mujer y de la sociedad.

Electrokinetic Remediation of Copper Mine Tailings: Evaluating Different Alternatives for the Electric Field

Due to the magnitude of the mining activity in Chile, it becomes necessary to find solutions to mitigate the impact of mining waste on the environment. One method that could be suitable for remediation of mining wastes is the use of electric fields for the removal of metals, the so-called electrochemical remediation: electrokinetic or electrodialytic remediation (EKR or EDR). Especially, metals such as copper, zinc, lead, and arsenic have been removed or concentrated when applying electric fields—and these metals are typically also found in mining waste. The use of this remediation technology will imply the periodic application of the method in order to remove the additional soluble copper that will be generated with time. Therefore, the remediation action for this heterogeneous solid waste is to remove the soluble copper in the tailings and in this way making the final residue more stable.