Gustavo Ferreira Coelho

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.

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.

Produtividade e componentes de produção da soja adubada com diferentes doses de fósforo, potássio e zinco

O correto incremento da produtividade agricola deve estar aliado ao avanco tecnologico no conhecimento das exigencias nutricionais de cada cultura, proporcionando, dessa forma, o correto uso de insumos na propriedade agricola. Com o objetivo de estudar a resposta de plantas de soja ao zinco (Zn) em relacao a diferentes doses de fosforo (P) e potassio (K), foi realizado este experimento no municipio de Palotina-PR. O solo foi classificado como Argissolo Vermelho-Amarelo eutrofico. Os tratamentos foram arranjados em esquema fatorial 3x3, constituindo tres formas de adubacao com P2O5 e K2O: sem adubacao, uma vez e duas vezes a recomendacao de adubacao pela analise de solo e tres doses de Zn (0; 2 e 4 kg ha-1). Como fonte de nutrientes, foram utilizados fosfato bicalcico para P, cloreto de potassio para K e sulfato de zinco para Zn. As doses de Zn aplicadas nao influenciaram, significativamente, a produtividade, nao sendo justificada a sua suplementacao na forma de adubacao de base. Ja a adubacao com P2O5 e K2O provocou significativo aumento da produtividade e aumento do numero de legumes por planta, com aumento das doses desses nutrientes no solo.

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.

Chemical Modifications of Cassava Peel as Adsorbent Material for Metals Ions from Wastewater

Residues from the processing of cassava roots (Manihot esculenta Crantz), or cassava peels, are evaluated as chemically modified adsorbents with H2O2, H2SO4, and NaOH, in the removal of metal ions Cd(II), Pb(II), and Cr(III) from contaminated water. Modified adsorbents were chemically characterized for their chemical composition and (point of zero charge), while adsorption tests determined the best conditions of pH, adsorbent mass, and contact time between adsorbent and adsorbate in the process of removal of the metal ions. Isotherms obtained from the preliminary results were linearized by Langmuir’s and Freudlich’s models. The thermodynamic parameters, such as , , and , were also evaluated. The modifying solutions proposed were effective in the modification of adsorbents and resulted in high capacity sorption materials. Equilibrium time between adsorbent and adsorbate for the solutions contaminated with metals is about 40 minutes. The Langmuir model adjusted to most results, indicating monolayers adsorption of Cd(II), Pb(II), and Cr(III). The values obtained for Langmuir show a higher adsorption capacity caused by chemical modifications, with values such as 19.54 mg Cd(II) per g of M. NaOH, 42.46 mg of Pb(II) per g of M. NaOH, and 43.97 mg of Cr(III) per g of M H2O2. Results showed that modified cassava peels are excellent adsorbent, renewable, high availability, and low-cost materials and a feasible alternative in the removal of metals in industries.

Adsorption of Cu (II) and Zn (II) from Water by Jatropha curcas L. as Biosorbent

Abstract The objective of this work was to evaluate the removal of Cu2+ and Zn2+ in water by means of the adsorption process using three biosorbents derived from jatropha biomass (bark, endosperm and endosperm + seed coat). The experiments were performed in batch and evaluated the effect of solution pH, adsorbent mass, contact time, different initial concentrations of the metals Cu2+ and Zn2+, and the temperature of the solution during the adsorptive process. By kinetics, the adsorption isotherms and thermodynamics the mechanisms that control the adsorptive process were evaluated. The optimal conditions for the realization of the adsorptive process for both metals were: solution pH of 5.0 and 8 g L-1 of adsorbent mass per volume of solution, with a contact time between adsorbent and adsorbate of 60 min. According to the Langmuir model, the maximum adsorption capacities for the bark, endosperm and endosperm + seed coat of Jatropha were, respectively, for Cu2+ 11.541, 20.475 and 22.910 mg g-1, and for Zn2+ 14.852; 15.888 and 14.674 mg g-1, with the predominance of chemisorption in monolayer. The three biosorbents derived from the biomass of Jatropha have potential for the remediation of water contaminated with Cu2+ and Zn2+.

Methods of extraction and bioavailability of zinc for the soybean culture fertilized with NPK+Zn

This work aims to evaluate the extractors Mehlich-1 and diethylene triamine pentaacetic acid (DTPA) and their extraction capacity for zinc (Zn) correlating them with the bioavailability of this nutrient in the soybean culture [Glycine max (L.) Merril] cultivated in a Eutrophic Red oxisol, in order to find better correlation between fertilization doses and plant absorption of zinc in conditions of the Parana Western region. The experiment was performed in 2008, in the city of Marechal Candido Rondon – Brazil, in completely randomized design. The treatments were arranged in 3×3 factorial scheme, consisting of three fertilization doses (N:P2O5:K2O in kg ha-1): without fertilization; recommended dose (4:40:40) and twice the recommended dose (8:80:80); and three Zn doses: 0.00; 1.00 and 2.00 kg ha-1. Between the evaluated extractors, Mehlich-1 presented higher capacity of Zn extraction in the studied soil. Concerning fertilization with Zn, though the doses show increment in the soil, no increase was found in the Zn concentration in leaf tissue. Key words: Micronutrients extraction, diethylene triamine pentaacetic acid (DTPA), Mehlich-1.

Production and nutrient accumulation in Tifton 85 (Cynodon dactylon (L.) Pers.) fertilized with swine manure in clayey soil

The aim of this study was to determine the production and nutrient content of Tifton 85 (Cynodon dactylon (L.) Pers.) fertilized with doses of swine manure and biofertilizer. The soil used in this study was a Rhodic Eutrudox. The treatments consisted of two forms of manure (in natura and biofertilizer), with four doses and four replications. Mean production of the grass in the first cutting based on fresh matter (FM) was 6,572 kg ha-1 and for dry matter (DM) 3,511 kg ha-1. The different types of manure had an effect on the Mg contents, and the doses had an effect on the contents of N, P, K, Mg, Cu, and Fe. In the second cutting, the mean production for FM was 7,590 kg ha-1 and for DM 3,632 kg ha-1; the sources had an effect on the P and Cu contents and the doses had an effect on the contents of N, P, K, Fe, Mn, Cu and Zn. By the obtained results, it was possible to conclude that the application of natural manure led to greater production of Tifton 85 when compared to the biofertilizer, and, furthermore, the leaf content of the nutrients N, P and K and of the micronutrients Fe, Cu and Zn increased according to the doses applied and sources used.