https://tede.unioeste.br/handle/tede/599 2026-06-27T17:21:30Z 2026-06-27T17:21:30Z Zanelatto, Thamires Mirian https://tede.unioeste.br/handle/tede/8470 2026-06-17T18:04:44Z 2025-11-17T00:00:00Z

Title: Adsorção de zinco a partir de cascas de arroz funcionalizadas: estudo em batelada e em coluna de leito fixo Autor: Zanelatto, Thamires Mirian Primeiro orientador: Palu, Fernando Abstract: Water contamination by heavy metals poses a critical threat to aquatic ecosystems and public health. Among these elements, zinc (Zn2+) stands out due to its high toxicity and persistence in the environment, compromising biodiversity and water potability. Conventional wastewater treatment processes have limitations in removing residual heavy metals, which underscores the need for alternative, higher-performance technologies. In this context, adsorption using agro-industrial residues, such as rice husks, emerges as a promising strategy for removing zinc at low concentrations, combining effectiveness with the promotion of the circular economy. Accordingly, this study aimed to evaluate the efficiency of functionalized rice husks for zinc adsorption in both batch and fixed-bed systems, given the lack of comparative data between these models. To this end, raw rice husks, whole and crushed (0,30-1,40 mm), were subjected to acid treatment (TA) with H3PO4, basic treatment (TB) with NaOH, and combined treatment (TC) with sequential application of both reagents at different concentrations. In batch experiments, preliminary tests assessed the effect of pH (4 and 5) and husk particle size on process performance, establishing the optimal condition as the use of crushed material at pH 5, a value supported by the electrochemical characterization of the solids and the zinc specification diagram. Under these conditions, the effect of chemical modification on metal removal was evaluated, identifying the TC 1,0-1,0 adsorbent as the most effective. This selection was corroborated by surface analysis, revealing functional groups with affinity for Zn2+ cations, such as SiO- and R-COO-Na+. The material was then subjected to kinetic studies, with data best fitting the pseudo-second order (PSO) model (qe: 0,88 meq g-1, k2: 1,55 g meq-1 min-1). Mass transfer dynamics were analyzed using the intraparticle diffusion model (IPDM), indicating external and internal resistances. In equilibrium tests, the Sips isotherm provided the best fit to experimental data (ns: 0,64; ks: 10,3 L meq-1, qmax: 1,18 meq g-1). Regeneration of the TC 1,0-1,0 adsorbent over three adsorption/desorption cycles with HCl and NaOH showed greater effectiveness under basic conditions, maintaining zinc removal capacity for up to 4 reuse cycles. In continuous operation, packed-column design and kinetic modeling were performed for TC 1,0-1,0 beds with different heights (5, 10, and 15 cm, at 5 meq L-1) and initial zinc concentrations (3, 4, and 5 meq L-1, at 15 cm). Higher metal contents reduced the column’s breakthrough time (tt,u), while increased bed height extended it. Maximum efficiencies were observed for the 15 cm bed at 3 meq L-1 (69,44%) and the 10 cm bed at 5 meq L-1 (68,44%). Breakthrough curve kinetics were best described by the modified dose-response (MDR) model (qMDR: 0,78-1,22 meq g-1, αMDR: 6,58-10,65), except for the 15 cm bed at 3 meq L-1, which was better represented by the Clark model (Ac: 44,13, rc: 0,11 min-1, nF: 1,03). Although the highest adsorption capacity occurred in fixed-bed operation, the TC 1,0-1,0 adsorbent showed significant zinc removal in both systems, corroborating its applicability in advanced water and wastewater treatment. Publisher: Universidade Estadual do Oeste do Paraná Tipo do documento: Dissertação

2025-11-17T00:00:00Z Hericks, Lais da Silva Pego https://tede.unioeste.br/handle/tede/8469 2026-06-17T18:06:29Z 2026-02-24T00:00:00Z

Title: Tratamento de biochar produzido a partir da pirólise de sabugo de milho para aplicação como substrato no cultivo hidropônico da alface (Lactuca sativa L.) Autor: Hericks, Lais da Silva Pego Primeiro orientador: Silva, Edson Antonio da Abstract: One way to reuse residual corn biomass, especially from the cob, abundant in the western region of Paraná, is by using it as raw material in the pyrolysis process to form biochar. Biochar is a porous-structured product with numerous applications and benefits, such as providing nutrients to plants, and is widely used in agriculture. This study aims to explore the potential of corn cob biochar, with and without treatment, as a substrate in hydroponic lettuce (Lactuca sativa L.) cultivation. Before conducting the pyrolysis, the residual corn cob raw material was characterized, and the moisture content was found to be 8,327±0,274%, ash content was 1,463±0,006%, and extractives were 6,400±0,347%. The corn cob pyrolysis tests followed a factorial experimental design 23+PC (central point), in which different pyrolysis conditions were studied, including temperatures of 441, 500, and 559 °C, residence times in the reactor of 0,5, 1,0, and 1,5h, and biomass particle sizes of 2, 3, and 4 mm. Mathematical models were developed to explain the experimental responses, and the global desirability tool was applied, identifying that test 3 (temperature of 441 °C, time of 1,5h, and biomass size of 2 mm) was the most suitable for maximizing the selected responses of yield and cation exchange capacity (CEC). Under these pyrolysis conditions, the yield for the biochar was 27,306%, and the CEC was 36,757 cmol kg-1. Biochar produced under the conditions of test 3 was treated with phosphoric acid, followed by neutralization with magnesium hydroxide (designated as B2), and treated with phosphoric acid + magnesium hydroxide + sodium selenite (designated as B3), with B1 being the untreated biochar. The phosphorus (P) concentration increased from the acid treatment of 2,491±0,101 mg L-1 to 25,093±0,488 mg L-1. After treatment with magnesium hydroxide, the magnesium concentration obtained was 10,736±0,184 mg L-1, an element that was not detected in B1. After treatment with selenium, the concentration obtained was 13,360±0,205 mg L-1. A solubility test was conducted to verify the concentration of this element transferred to water, as the goal was to evaluate the potential of the treated biochar as a substrate in hydroponic cultivation, and excessive selenium concentrations can be toxic to plants. The selenium concentration obtained in the water after the solubility test was 0,725±0,015 mg L-1, appropriate for application in hydroponic cultivation. The B1 and B3 biochars were used as substrates in the hydroponic cultivation of lettuce at a biochar:perlite ratio of 1:1 (v/v) for B3 and 1:1 (v/v), as well as 0.5:1 (v/v) for B1. The highest growth parameters were obtained when applying the treated biochar, showing that the treatment was effective. After 4 weeks of cultivation, the average number of leaves reached 7,31±0,20, the average aerial part height was 11,25±0,34 cm, and the average leaf width was 4,81±0,10 cm. Based on the results obtained, it can be concluded that the biochars produced in the experimental trials were of good quality and can be applied in hydroponic lettuce cultivation, especially the trial 3 treated with P, Mg, and Se. Publisher: Universidade Estadual do Oeste do Paraná Tipo do documento: Dissertação

2026-02-24T00:00:00Z Barros, Ruth Ribeiro Naves https://tede.unioeste.br/handle/tede/8398 2026-04-29T18:49:50Z 2023-08-29T00:00:00Z

Title: Avaliação da cinética, equilíbrio e termodinâmica na dessulfurização adsortiva do dibenzotiofeno utilizando o carvão ativado da casca do coco de dendê Autor: Barros, Ruth Ribeiro Naves Primeiro orientador: Modenes , Aparecido Nivaldo Abstract: The Petroleum-derived fuels are widely used worldwide and contain contaminants such as sulfur compounds (SO2, H2S, SO4 2-, H2SO4, S2-, SO3 2-) that can harm human health and the environment. Environmental legislation has helped establish standards and guidelines for reducing sulfur emissions, opening the way for the study of alternative methods for the removal of these compounds. The objective of this work was to evaluate the adsorptive desulfurization of thiophenic compounds and the efficiency of activated carbon from dendê coconut shell (CACD) with aluminum impregnation using the incipient method and oxidative treatment. Adsorption experiments (kinetics and equilibrium) with the removal of dibenzothiophene (DBT) as a single-component system, were conducted in a closed and batch system. The adsorption experiments (kinetics and equilibrium), for removal of the compound dibenzothiophene (DBT) in a single-component system, were carried out in a closed and batch system. To describe the adsorption equilibrium, isotherm models such as BET, SIPS, Freundlich, Langmuir, Tóth, and Radke-Praunitz models were used, with the SIPS model showing the best fit for the phenomenological parameters. In the equilibrium isotherm, the SIPS model had a maximum adsorption capacity (qmax) at a temperature of 30 °C of 0.6626 mmol g-1, showing a significant interference in thermodynamic models; the higher the temperature, the lower the affinity of the adsorbent to the adsorbate, and the lower the adsorption. For the kinetic data, the SIPS HSDM model was used, demonstrating that all limiting steps were completed, with the adsorption molecule having difficulty in inserting into the adsorbent, as it has micropores. The results of kinetics, equilibrium isotherms, and thermodynamics show that activated carbon from dendê coconut shell (CACD) proved to be efficient in the adsorptive desulfurization of dibenzothiophene (DBT). Publisher: Universidade Estadual do Oeste do Paraná Tipo do documento: Dissertação

2023-08-29T00:00:00Z Boico, Debora Guerino https://tede.unioeste.br/handle/tede/8397 2026-04-29T18:18:03Z 2016-08-25T00:00:00Z

Title: Utilização do permeado de soro de leite na produção de celulases por fermentação em estado sólido do bagaço de cana Autor: Boico, Debora Guerino Primeiro orientador: Hasan, Salah Din Mahmud Abstract: The great market potential and the important role that cellulases impact on bioenergy and organic products industries cause a great motivation in the development of improved cellulolytic enzymes diming to the hydrolysis of cellulose of plant cell walls. These cellulases must have some necessary characteristics for application in biorefineries as high catalytic efficiency of insoluble cellulosic substrates. The objective of this study was to evaluate the feasibility of using whey permeate, in the culture medium composition for the enzymatic complex production of cellulases, such as FPases, CMCases, xylanase and β-glucosidase by solid state fermentation of bagasse sugarcane using the fungus Aspergillus niger. It was evalusted the optimize the production process of cellulolytic enzymes by SSF, evaluating the influence of pH and concentration of whey permeate the culture medium. Studies were also performed on the enzymatic hydrolysis of sugarcane bagasse by an experimental design. Regarding the enzymatic production it showed good results for FPase enzymes, CMCase and β-glucosidase. For FPase there was a production of 37,0 U.gms-1. For the xylanase there was a production of 2,6 U.gms-1.For CMCase there was a production of 39,0 U.gms-1. For β-glucosidase there was a production of 18.0 U.gms-1 in 48 h of fermentation. In time the production kinetics, it used the optimal conditions of fermentation solid-state 60 g.L-1 PSL and pH 5.0 for FPase enzymes, CMCase and β-glucosidase. This study indicated that the fungus Aspergillus niger showed considerable amount of enzymes cellulolytic complex except the xylanase enzyme, stimulating the continuity of study for other enzymes to alter the nutritional conditions of cultivation to increase production of cellulases. Publisher: Universidade Estadual do Oeste do Paraná Tipo do documento: Dissertação

2016-08-25T00:00:00Z