Remoção de preto reativo 5 e bisfenol A por adsorção com carvão ativado e cinza de casca de arroz

• Ano de defesa: 2021
• Autor(a) principal: Cavalcante, Luan Costa
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Tecnológica Federal do Paraná; Curitiba; Brasil; Programa de Pós-Graduação em Ciência e Tecnologia Ambiental; UTFPR
• Palavras-chave em Português: Adsorção; Água - Purificação - Tratamento biológico; Corantes; Carbono ativado; Indústria têxtil; Adsorption; Water - Purification - Biological treatment; Colorings matter; Carbon, Activated; Textile industry; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA; Ciências Ambientais
• Link de acesso: http://repositorio.utfpr.edu.br/jspui/handle/1/25703

Since the 1970s, the presence of micropollutants in water has been increasingly common, such as the azo dye reactive black 5 (RB5), which is widely used in the textile industry, and endocrine disruptors such as bisphenol A (BPA), that have been used in large scale manufacturing of plastics. These and other micropollutants can have adverse effects on the environment, causing damage to both the environment and public health due to their high carcinogenic potential and hormonal changes. Adsorption is a process used to remove micropollutants from water, the use of agro-industrial waste can be a viable alternative as an adsorbent material, such as rice husk, a waste material from which Brazil generates more than 20 million tons per year. This study aimed to evaluate the removal of RB5 and BPA in water using commercial powdered activated carbon (PAC) and rice husk ash (RHA) as adsorbent materials. The study was initially carried out with PAC to evaluate the best RB5 removal under different pH conditions (2-12). For the performance of RB5 kinetic tests with PAC and RHA, 0.4 g L-1 for PAC and 15 g L-1 for RHA were adopted as the best dosages, and 90 mg L-1 of RB5 solution’s concentration. To perform the isotherm studies, RB5 concentration was varied from 60 to 240 mg L-1, and the adsorption equilibrium (qe) for PAC was obtained after 40 minutes with a higher qe at pH 2. The most favorable adsorption model was Langmuir (R² = 0.974) with a maximum monolayer adsorption capacity (qmax) of 154.17 mg g-1. Thermodynamic studies were carried out at different temperatures (298, 308 and 318 K) for both materials (PAC and RHA) and ΔH° and ΔG° values were negative, indicating that the adsorption is an exothermic and spontaneous process. As with RB5, the removal of BPA by RHA was also evaluated as a function of pH (2-12). For the kinetic study of BPA using RHA, a 15 g L-1 adsorbent dosage and 100 mg L-1 concentration of BPA solution were used. For the evaluation of the isotherm, the BPA concentration varied from 60 to 240 mg L-1, reaching the adsorption equilibrium (qe) after 240 minutes, and a higher qe at pH 2. The most favorable adsorption model was the Redlich-Peterson model (R² = 0.986), showing a αRP of 0.689, which indicates that the model fits better the Langmuir model, with a maximum monolayer adsorption capacity (qmax) of 5.76 mg g-1. Thermodynamic studies were carried out at different temperatures (298, 308 and 318 K), and the results shown through the study using RHA for BPA adsorption is that the ΔG° values were negative and the ΔH° values were positive, indicating that the adsorption was a spontaneous and endothermic process. Particle size effect studies with RHA for RB5 removal for 100 and 200 mesh showed removal of approximately 60% at pH 2, and no significant difference was observed in the removal. In the study of BPA removal, there was no difference in varying pH and particle sizes. Although the RHA has shown lower adsorption capacity in the removal of RB5 and BPA, this material may prove to be an economical alternative for the adsorption of micropollutants in low concentrations.