Potencialidades do uso de rocha basáltica para aplicação no processo de tratamento de efluentes

Abstract

Basalt is a rock formed by basaltic magma abundant on planet Earth. It is considered a fine-grained extrusive rock due the magma cooling rapidly after a volcanic eruption. Its composition consists of an average of 52% SiO2, 14% Al2O3, and 10% Fe2O3 as the main components. Basalt is found in large igneous provinces, which are large concentration of land in which there has been great volcanic activity. In Brazil, a large igneous province extends through states as Paraná, São Paulo, and Minas Gerais and other countries such as Paraguay. Large volumes of basaltic magma are placed and, consequently, a well-established mining practice in the region. The rock is used in civil construction and the basalt powder is one of the main residues of the mining activity. The powder preserves the chemical composition from rock and can be used in various applications. One of the main uses of basalt powder is as a natural fertilizer in which the powder is applied to the soil to slowly release substances to keep the soil remineralized for long periods. Another practice is to use basaltic rock dust as a base material for zeolites creation, which are porous materials that can be used in catalytic activities. Basalt powder can be used as a filler to new materials formation, mainly polymers and civil industry materials such as mortars and concrete. In all cases, basalt provides mechanical and thermal properties improvements. Another area where basalt powder is a promising material is in the field of wastewater treatment. In the gaseous effluents treatment, basalt powder is the subject of preliminary studies to identify basalt's ability to sequester carbon and transform it into carbonate minerals. In the liquid effluent treatment, adsorption and a class of processes called Advanced Oxidative Processes stand out in which photocatalysis, Fenton, and photo Fenton were investigated together with basalt powder as a catalyst concerning the effectiveness of these processes in treating molecules complexes and industrial waste. In the current work, the advantages and challenges in the various applications of rock powder were discussed, focusing on the treatment of effluents by advanced oxidative processes. The main advantage of basalt powder including the large amount available on the planet, its rich composition in many components, its specific surface area and the low cost involved in its acquisition, which adds to its efficiency as a catalyst of wastewater treatment. The main challenges lie in the fact that it is a relatively new research segment, mostly preliminary studies. Basalt powder has the potential to be a great ally in the treatment of effluents, but further studies are needed on the range of substances degraded and their compatibility with the rock.