Caracterização de argilas bentonitas e diatomitas e sua aplicação como adsorventes

Five samples of natural clays denominated: diatomite, CN-20, CN-29, CN-40 and CN-45 from Aliança Latina LTDA were characterized by differents supplementary techniques such as: XRD, chemical analysis, adsorption N2 measurements, infrared spectroscopy analysis, thermogravimetric analysis. Clays were tested in adsorption of blue methylene. All of isotherms adjust in a model of physics adsorption with formation of multilayers, however in the case of diatomite was a favorable adsorption (type II) and the CNs were a not favorable adsorption (type III). In the case of CNs had flocculation of clay in high concentration of coloring

Eight basic principles for the elaboration of public policies and development projects for the Pantanal

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2024 The Author(s). Conservation Science and Practice published by Wiley Periodicals LLC on behalf of Society for Conservation Biology. The Pantanal is considered the largest continuous freshwater wetland in the world, and its sustainable use requires a unified conceptual framework. The lengthy process to establish public policies has contributed to the increasing vulnerability of the Pantanal. Given the need for a conceptual basis to help this process, we elaborate a list of eight basic principles based on the accumulated scientific evidence: (i) Consider the Paraguay River Basin a management unity; (ii) Establish rules that follow the concept of restricted use approach; (iii) Ensure the ecologically sustainable use of the Pantanal; (iv) Maintain the environmental heterogeneity and functionality in the Pantanal landscapes; (v) Maintain the hydrological integrity and connectivity; (vi) Ensure the environmental representativeness of the protected areas network; (vii) Provide economic incentives for conservationist use of the land; and (viii) Recognize and protect traditional people, their values, resources, and way of living. However, the elaboration of public policies should be a participatory and inclusive decision‐making process towards a more just and sustainable future

Zeolite A synthesis employing a brazilian coal ash as the silicon and aluminum source and its applications in adsorption and pigment formulation

Zeolite A was synthesized using the coal ash from Siderópolis/RS - Brazil. The synthesis was based on a standard IZA synthesis using coal ash as the Si and Al source. XRF analysis showed that the coal ash has a Si/Al ratio of 1.52, which is close to the Si/Al ratio required to produce zeolite A (1.0). The synthesized materials were analyzed by XRD, SEM and N2 adsorption. More crystalline materials were obtained during synthesis when an additional treatment was applied at a temperature of 353 K at the dissolution of NaOH step. The product formed after 4 hours was the most crystalline, but even the product formed after 1 hour proved to be better than that formed using the standard 4 hours IZA synthesis. The zeolites synthesized by this method had an adsorption capacity of 120 mg.g-1 for Ca2+, half the capacity of commercial zeolite A (300 mg.g-1). It was not possible to obtain blue or green pigments using the synthesized zeolite A

Adsorção de xantatos sobre pirita Adsorption of xanthate on pyrite

<abstract language="eng">This paper presents a study of adsorption of xanthate with alkyl chain of two (C2XK), four (C4XK) and eight (C8XK) atoms of carbon, on pyrite from Santa Catarina, Brazil. The results showed that pyrite surface changes from hydrophilic to hydrophobic when xanthate is adsorbed increasing the contact angle to 35º for C2XK, and to 90º for C4XK and C8XK. The rate of flotation of pyrite particles after adsorption increases with the increase of the number of carbon atoms in the alkyl chain in agreement with the results of contact angle measurements

Síntese da zeólita cancrenita a partir de caulim: uma alternativa viável à redução de impactos ambientais

<div align="justify">A síntese da zeólita cancrenita foi realizada aproveitando três caulins denominados AD44, Mina e Reagen, utilizados em substituição às fontes de silício e alumínio já empregadas na síntese de peneiras moleculares, geralmente caras e que necessitam de tratamentos químicos para sua obtenção. Os dois primeiros são caulins naturais e o ultimo é um caulim comercial. Estas argilas foram usadas na forma natural e calcinada a 900oC. As argilas e os materiais obtidos foram caracterizados por difração de raios-X, medidas de área superficial BET e microscopia eletrônica de varredura. Os resultados mostraram que as argilas calcinadas conduzem à fase cancrenita com maior cristalinidade quando comparada com as argilas naturais. Diferentes fases, tais como sodalita e mesofases entre cancrenita e sodalita também são formadas.<br><br>Abstract The synthesis of cancrinite zeolite was accomplished by three types of kaolins called AD44, Mina and Reagen. These materials were used as aluminium and silicon sources in substitution of expensive reactants. The first two types are natural kaolin and the last one is a commercial. These clays were used in natural and calcinated (900ºC) forms. The clays and the obtained materials were characterized by X-ray diffraction (XRD) specific superficial area (BET) and scanning electronic microscopy (SEM). The results showed that calcinated clays lead to cancrinite phases with higher cristallinity when compared with the natural clays. Different phases such as sodalite and mesophases between sodalite and cancrinite were formed too.</div