Tratamento de águas residuais da indústria têxtil com membrana cerâmica de baixo custo utilizando resíduos agroindustriais: preparação, caracterização e avaliação

Abstract

Given the high demand for water resources in the textile industry and the growing concern for sustainability, new methods for wastewater treatment have emerged in recent years. The use of membranes for the treatment of these effluents stands out as an effective and promising alternative due to their excellent physical and chemical properties. In this context, the study of accessible and low-cost raw materials for the production of ceramic membranes becomes essential for the development of sustainable and economical solutions for textile effluent treatment. In this work, low-cost ceramic membranes were developed using chocobofe clay, sugarcane bagasse ash (CBCA), and kaolin, with the aim of treating textile effluents. The raw materials were characterized by techniques such as X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), thermogravimetric analysis (TGA), and particle size and distribution analysis. The membranes were then produced with CBCA proportions ranging from 0 to 50%, through dry uniaxial pressing in a hydraulic press, under a pressure of 1 ton and molding time of 60 seconds, followed by sintering at 650 °C for 3 hours. The resulting ceramic membranes were characterized by a series of techniques: XRD, linear diameter shrinkage, mass loss, density, apparent porosity, water absorption, mechanical strength, contact angle, and pure water flux. They were also evaluated for their efficiency in rejecting methylene blue dye solution and recyclability. The ceramic membranes showed porosity between 41.45 and 44.82 %, suggesting that the addition of CBCA had little influence on this property, and the average pore radius ranged from 0.23 to 0.27 μm. A decrease in the mechanical strength of the membranes was observed, from 40.05 to 10.36 MPa as CBCA was added to the composition. The pure water flux and permeate flux increased with higher CBCA concentration in the membranes. In the rejection of methylene blue dye, all ceramic membranes demonstrated high efficiency, with rejection rates ranging from 99.90 to 97.70 %. The recyclability test evaluated the C30 and C50 ceramic membranes' performance over an extended period, indicating better results in the C30 membrane. A preliminary cost estimate showed that the raw material costs ranged from R$ 37.40 to R$ 61.17 per square meter, and the total cost, including energy costs, ranged from R$ 901.24 to R$ 929.27 per square meter.