Atualmente a contaminação do solo se dá principalmente pela deposição inadequada de resíduos contaminados, causando danos a longo prazo e representando um risco eminente para o meio ambiente e também para o ser humano. Este trabalho propôs a investigação ambiental do solo na condomínio residencial do bairro Volta Grande IV, situado na cidade de Volta Redonda- RJ. Tal área foi utilizada como depósito de resíduos de siderurgia, classificados como resíduos perigosos segunda a NBR 10004 da ABNT. Após o encerramento do depósito, foi construído no local um conjunto habitacional que atualmente serve como residência para aproximadamente 200 famílias. Desta forma, o objetivo do trabalho foi realizar um estudo de caso do histórico de contaminação no bairro Volta Grande IV, além de diagnosticar a existência de metais pesados em solos presentes em áreas públicas ainda não impermeabilizadas. A determinação dos metais presentes em tais áreas seguiu a metodologia de digestão por água régia, especificada na ISO 11466/1995. Os metais selecionados para análise neste trabalho foram: chumbo (Pb), níquel (Ni), zinco (Zn) e cobre (Cu), estando estes, com exceção do Pb, acima dos valores de referência estabelecidos pela CETESB. Também foi determinado o pH das amostras de solo, os quais se apresentaram alcalinos em todos os pontos de coleta.
In this study β-zeolite, ferrierite and partially delaminated PREFER (precursor of ferrierite) zeolites with several chemical and textural properties were synthesized for the removal of zinc and lead ion metals from their respective solutions. Adsorption experiments involving the suspension of tiny amounts of these solids in aqueous solutions containing either Zn or Pb showed that the removal of these metals at a considerable extent may be attained. Among the studied materials, β-zeolite displayed the better performance in metal ion removal, which may be ascribed to its higher aluminum content, surface area and external surface area, that allows a greater density and availability of ion adsorption active sites. Kinetic data from a pseudo-second-order model indicate that the chemical interaction among metal ions and active sites is the rate-limiting step. Furthermore, the better performance of the β-zeolite displayed in reusability testing makes it a potential adsorbent for future applications in the treatment of effluents containing toxic metals.
The objective of this study was to evaluate the influence of biochar saturation doses on the cumulative loss of water in a Yellow Latosol typical of Central Amazonia. The experiment was conducted in a greenhouse of the National Institute of Research of the Amazon -INPA, in Manaus-AM. Biochar was used from the pyrolysis of brown urchins and a secondary forest soil. A completely randomized design with five biochar doses (0, 20, 40, 60 and 80 t ha -1 ) was used with four replicates, each experimental unit consisting of a plastic vessel with 2500 g of soil with biochar. The observed variables were the amount of water required for soil saturation and the cumulative loss of water in seven periods (24 h, 48 h, 72 h, 96 h, 120 h, 144 h and 168 h). The water measurements required for saturation were based on dry soil and, while losses were calculated based on the subtraction of the saturated soil mass and the wet mass of each period. The biochar doses did not significantly influence the amount of water required for saturation of the studied soil. Attenuated water losses were observed with the application of 20 and 40 t ha -1 of biochar. The higher doses of 60 and 80 t ha -1 of biochar promoted the greatest accumulated losses of soil water.
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