Daniel Schwantes

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.

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...

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+.

Disponibilidade dos metais pesados tóxicos cádmio, chumbo e cromo no solo e tecido foliar da soja adubada com diferentes fontes de NPK+Zn

Os fertilizantes utilizados para suprir micronutrientes podem apresentar metais pesados toxicos em sua composicao que podem proporcionar severas consequencias ao meio ambiente. Plantas cultivadas na presenca de determinadas concentracoes de elementos toxicos podem oferecer risco de contaminacao, pois os acumulam em seus tecidos. Desse forma, neste trabalho objetivou-se avaliar a disponibilizacao dos metais pesados toxicos Cd, Pb, e Cr para o solo e tecido foliar da cultura da soja, cultivada a campo e fertilizada com um formulado N:P2O5:K2O e diferentes fontes de Zn. O delineamento experimental utilizado foi o de blocos ao acaso, em esquema fatorial [(5+1)x2], com tres repeticoes. Os tratamentos foram constituidos de cinco diferentes fertilizantes NPK+Zn (quatro fontes com Zn e uma sem Zn), um tratamento sem adubacao e duas doses de adubacao (uma vez e o seu dobro). Com base nos resultados obtidos foi concluido que a aplicacao dos tratamentos disponibilizou Cd, Pb e Cr para as plantas de soja e para o solo do experimento nas duas doses de adubacao utilizadas.

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.