Ana Paula Meneghel

Removal of cadmium from water using by-product Crambe abyssinica Hochst seeds as biosorbent material

The effectiveness of Crambe abyssinica Hochst seeds by-product as a biosorbent for the removal of cadmium ions from wastewater was analyzed. The biomass of crambe was characterized by scanning electron microscopy, infrared spectroscopy and determining the point of zero charge. The optimum adsorption conditions obtained were 400 mg of biomass in a solution of pH 6.0 and contact time of 60 min to remove 19.342 mg g(-1) cadmium ions. The isotherms of adsorption were constructed and, according to the mathematical linearization, the best fitting followed the Freundlich and Dubinin-Radushkevich models, describing a multilayer adsorption and chemical interaction, also confirmed by the pseudo-second order model and enthalpy value. In the desorption process, about 79% of cadmium ions that had been adsorbed were recovered. The same conditions applied for studying the isotherms of adsorption and desorption were used for comparative study with activated carbon. It was concluded that the use of crambe by-product as biosorbent for cadmium removal in wastewaters was not only a viable alternative to activated carbon, but also required no previous treatment, so it represents a sustainable material with high applicability and low environmental impact.

Biosorption and removal of chromium from water by using moringa seed cake (Moringa oleifera Lam.)

This study evaluated the adsorption capacity of chromium from contaminated aqueous solutions by using Moringa oleifera Lam. seeds. Parameters such as solution pH, adsorbent mass, contact time between solution and adsorbent, isotherms, thermodynamic, kinetics, and desorption were evaluated. The maximum adsorption capacity (Qm) calculated to be 3.191 mg g-1 for the biosorbent. Activated carbon was used for comparison purposes in addition to the biosorbent. The best fit was obtained by the Langmuir model for both adsorbents. The average desorption value indicated that both the biosorbent and activated carbon have a strong interaction with the metal. The results showed that the biosorbent has advantages owing to its low cost and efficiency in Cr3+ removal from contaminated waters.

The use of Crambe abyssinica seeds as adsorbent in the removal of metals from waters

This study aimed to evaluate the efficacy of crambe seeds (Crambe abyssinica Hochst) as adsorbent material in the removal of the toxic metals cadmium, lead and chromium from contaminated solutions. The byproduct was obtained from oil extraction of crambe seeds in a Soxhlet system. In kinetic tests, the adsorbent masses had varied in solutions containing the metals under pH 5.0 and 7.0. Metal concentrations were determined by flame atomic absorption spectrometry (FAAS). According to optimal conditions found, the adsorption assays were performed for obtaining the isotherms of each metal, which were linearized in agreement with the mathematical models of Langmuir and Freundlich. According to the obtained results, the adsorbent was effective in removing the assessed metals in aqueous solutions, being feasible its employment as an alternative material for the adsorption of metals, besides being a byproduct, which has undergone no prior treatment.

A Crambe abyssinica seed by-product as biosorbent for lead(II) removal from water

AbstractThis study assessed the performance of a Crambe abyssinica Hochst seed by-product as biosorbent for removing lead [Pb(II)] ions from water. The material was characterized by scanning electron microscopy and infrared spectroscopy techniques as well as by point of zero charge (pHPCZ) measurement. The following parameters were determined after adsorption experiments: solution pH, biosorbent mass, contact time, and temperature. The optimal conditions were found to be mass –400 mg, solution pH 7.0, and equilibration time –20 min; they were used for performing isotherm tests. The isotherms were best fitted to the Freundlich and Dubinin–Radushkevich mathematical models. Based on the results of kinetic and thermodynamic studies (pseudo-second-order kinetics, negative change in Gibbs free energy, positive change in enthalpy and low ion desorption rate), it was established that the Pb(II) ions interacted forcefully with the biosorbent, thus confirming that a spontaneous endothermic chemisorption process too...

Applicability of Crambe abyssinica Hochst. byproduct as biosorbent in the removal of chromium from water

espanolEl objetivo de este estudio fue evaluar la eficacia del uso de subproducto de semillas de crambe como biosorbente en la eliminacion del metal pesado cromo a partir de soluciones contaminadas. Por medio de microscopia electronica de barrido, espectroscopia infrarroja y determinacion del punto de carga cero se realizo la caracterizacion del biosorbente. Se analizo la influencia de diferentes condiciones en la adsorcion de iones, tales como soluciones a diferentes condiciones de pH, variacion de las masas de biosorbente, tiempo de contacto y temperatura, y las concentraciones de metal se determinaron por espectrometria de absorcion atomica de llama. En los ensayos para obtener las isotermas, los modelos matematicos de Freundlich y Dubinin-Radushkevich fueron los que mejor ajustaron los datos experimentales. El estudio de desorcion demostro una intensa interaccion entre el metal y el adsorbente, lo que confirma los datos del modelo de pseudo-segundo orden y energia media de Dubinin-Radushkevich para quimisorcion. La maxima capacidad de adsorcion del biosorbente se estimo en 6,807 mg.g-1. Para el estudio comparativo con un adsorbente comercial se utilizo carbon activado en pruebas de adsorcion y desorcion. Basandose en estos resultados, se concluyo que el subproducto fue eficaz en la eliminacion de cromo de soluciones acuosas, y su uso como un material alternativo viable para la eliminacion de este metal, ademas de ser un subproducto, que no ha sufrido tratamiento previo. EnglishThe aim of this study was to evaluate the efficacy of using crambe seeds byproduct as biosorbent in the removal of chromium heavy metal from contaminated solutions. By means of scanning electron microscopy, infrared spectroscopy and the determination of the point of zero charge was performed the biosorbent characterization. The influence of various conditions on the ions adsorption, such as solutions at different pH conditions, variation of the biosorbent masses, contact time and temperature were investigated, and the metal concentrations determined by atomic absorption spectrometry flame mode. In trials to obtain the isotherms, the mathematical models of Freundlich and Dubinin-Radushkevich best fitted the experimental data. The desorption study demonstrated intense interaction between the metal and adsorbent, which confirms the data from the pseudosecond order model and mean energy of Dubinin-Radushkevich model for chemiosorption. The maximum adsorption capacity of biosorbent was estimated at 6.807 mg.g-1. To comparative study with a commercial adsorbent, activated carbon was used for tests of adsorption and desorption. Based on these results, it was concluded that the byproduct was effective in removing chromium from aqueous solutions, and its use as a viable alternative material for this metal removal, in addition to being a byproduct, which has not suffered pretreatment.

Applicability of Moringa oleifera Lam. pie as an adsorbent for removal of heavy metals from waters

This study evaluated the efficacy of moringa seeds (Moringa oleifera Lam.) as an adsorbent material for removing toxic heavy metals such as cadmium, lead, and chromium from contaminated solutions. The effect of the adsorbent mass was investigated at two pH conditions (5.0 and 7.0). The optimized conditions were 0.300 g of adsorbent at pH 5.0, used for the isotherms construction, and linearized according to Langmuir and Freundlich models. Results showed that cadmium adsorption was similar in both the models used. For lead, the Freundlich model had the best adjustment and chromium was better adjusted by the Langmuir model. It was concluded that the adsorbent was effective in the remediation of solutions containing cadmium, lead and chromium, thus, its use as sustainable alternative material is feasible, since it has low cost, does not need a previous treatment and it is a byproduct.

Studies of Pb2+ adsorption by Moringa oleifera Lam. seeds from an aqueous medium in a batch system

The efficiency of Moringa (Moringa oleifera Lam.) seeds for removing lead ions (Pb(2+)) from water was evaluated. Parameters such as solution pH, adsorbent mass, contact time between solution and adsorbent, isotherms, thermodynamic, kinetics, and desorption were evaluated. The maximum adsorption capacity of the biosorbent was found to be 12.24 mg g(-1). In order to verify the effectiveness of this material, comparative studies were performed with activated carbon under the same optimal conditions for the construction of isotherms and the desorption process. Average desorption rate values led to the assumption that a strong interaction took place between the adsorbents and the metal ions. Thus, it has been concluded that the biosorbent studied herein can be considered very effective and feasible for remediating Pb(2+)-contaminated solutions, since this material is itself an untreated and low-cost byproduct.