Oxidação fotoquímica - UV/H2O2 - para degradação de poluentes em efluentes da indústria têxtil

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Ambiental

Optimization of Fe and Mn Removal from Coal Acid Mine Drainage (AMD) with Waste Biomaterials: Statistical Modeling and Kinetic Study

The main characteristics of coal acid mine drainage (AMD) are a low pH and high concentrations of sulfate and diferent metallic ions. Response surface methodology using the central composite rotatable design (CCRD) model was used to optimize the parameters for AMD remediation with aquaculture farming waste [shrimp shell (SS) and mussel byssus (MB)]. SS was chosen due to its high chitin (a metal sorbent) and calcium carbonate (an acidity neutralizing agent) content, and MB because of its potential synergistic efect for the treatment. The coefcient of determination and standard error results from the analysis of variance have shown the model to be adequate. The predicted values were in good agreement with the experimental values. The best experimental conditions established from the statistical study were 136 rpm, 11.46 g L−1 SS and 71.6 g L−1 MB. CCRD can efciently be applied for modeling the AMD remediation with biomaterials and is an economical way of obtaining the maximum amount of information in a short period of time with the fewest number of experiments. Additionally, fve kinetic models, i.e., pseudo-frst-order, pseudo-second-order, intraparticle difusion, Bangham and Elovich equation, were tested to investigate the adsorption mechanisms. The kinetic studies revealed that a 200 min contact time is sufcient to transform AMD into water suitable for non-potable reuse. The pseudo-second-order model provided the best ftting of the experimental data, indicating a chemical adsorption mechanism. This research shows the suitability of the proposed treatment, and the information is valuable for designing a low-cost remediation process for AM

REMOVAL OF ORGANIC MATTER FROM WATER DISCARDED BY PAPER AND CELLULOSE MILLS AFTER UV/H2O2 TREATMENT

aper and cellulose mills effluents are composed by several combinations of chemical reagents used in productive stages and of substances originating from raw material, used to produce paper and cellulose pulp. Considering the volume of effluents generated by such industries and the current crisis of water  resources, it is blatant the need of an efficient treatment for the discarded water. The advanced oxidative processes constitute an attractive option for treating several effluents. They are capable of promoting degradation and even mineralization of refractory pollutant particles. The current paper looks forward to assessing the performance of the UV/H2O2 process in removing organic matter present in the effluent of a paper mill. The research was carried out in a photochemical reactor with active capacity of 1300 mL. As source of UV radiation, it was used a medium pressure mercury lamp of 125 W. During 120 minutes of UV irradiation, six H2O2 concentrations were testes, varying between 15 and 200 mg.L-1. The results revealed the effectiveness of the process when removing 84% of the CDO and 91% of the BOD5. The performance of the UV/H2O2 process was influenced by the availability of H2O2 and the time of UV irradiation

Sulfate removal from mine-impacted water by electrocoagulation: statistical study, factorial design, and kinetics

This work aimed to remove sulfate and acidity from mine-impacted water (MIW) via electrocoagulation (EC), a technique which stands as an advanced alternative to chemical coagulation in pollutant removal from wastewaters. The multiple electrochemical reactions occurring in the aluminum anode and the stainless steel cathode surfaces can form unstable flakes of metal hydroxysulfate complexes, causing coagulation, flocculation, and floatation; or, adsorption of sulfate on sorbents originated from the electrochemical process can occur, depending on pH value. Batch experiments in the continuous mode of exposition using different current densities (35, 50, and 65 A m−2) were tested, and a statistical difference between their sulfate removals was detected. Furthermore, the intermittent mode of exposure was also tested by performing a 22-factorial design to verify the combination with different current densities, concluding that better efficiencies of sulfate removal were obtained in the continuous mode of exposition, even with lower current densities. After 5 h of electrocoagulation, sulfate could be removed from MIW with a mean efficiency of 70.95% (in continuous mode of exposition and 65 A m−2 current density), and this sulfate removal follows probable third-order decay kinetics in accordance with the quick drop in sulfate concentration until 3 h of exposure time, remaining virtually constant at longer times

Nonwoven from cigarette butt applied in pre-treatment of surface water

This study aimed to evaluate a nonwoven (NW) production and performance from cellulose acetate fiber from cigarette butts andapplied to a filtration system for surface water pre-treatment. The system had a surface area of 528 cm2, cellulose acetate from cigarette butt as filter media, was used and was fed with surface water from a pond. In order to evaluate the treatment performance of the filtration system were evaluated in the raw water (RW) and the filtered water (FW) the classical parameter of water quality as turbidity, total suspended solids (TSS), apparent color, true color, and total organic carbon (TOC) and heavy metals (iron, copper, and cadmium). Moreover, the presence of nicotine was investigated in the FW. The results showed a mean removal efficiency in order to 62.01%, 54.42%, 50.36 %, 6.73%, and 5.20% for turbidity, TSS, apparent color, true color, and TOC, respectively. The removal of metals varied in the order of 72.26%, 9.61%, and 2.12% for cadmium, iron, and copper, respectively. The presence of nicotine in RW and FW was not identified. In this way, besides reducing the negative environmental impacts caused by cigarette butts present in the environment, the developed technology showed potential for removing pollutants present in surface waters

Tannin extraction from grape stems through a solid-liquid process: optimizing efficiency by applying the response surface methodology / Extração de tanino do caule da uva por meio de um processo sólido-líquido: otimizando a eficiência aplicando a metodologia de superfície de resposta

Viticulture is an agro-industrial sector that produces large amounts of waste, with grape seeds, bagasse, and stems standing out among the main types of waste produced. This study evaluated the effects of extraction conditions of total and condensed tannins from grape stems through a solid-liquid process using the response surface methodology. Contact time between matrix and solvent and the concentration of ethanol in the solvent were monitored as independent variables. Contact time varied between 12 and 24 hours. The extraction solvent was composed of a mixture of ethanol and water in proportions of 0, 50, and 100% (v/v). Total tannins were quantified by the Folin-Ciocalteu method in tannic acid equivalents. Condensed tannins were quantified by the vanillin method in catechin equivalents. Response surface methodology pointed out similar conditions for the extraction of total and condensed tannins. Best yields for total tannins were achieved with a contact time of approximately 21.18 hours and a hydroalcoholic solvent composed of 51.65% ethanol. Regarding condensed tannins, the contact time was slightly inferior, with the best yields obtained in 19.31 hours with a hydroalcoholic solvent composed of 49.19% ethanol. The tannic extract obtained under optimized conditions according to the results of the response surface methodology was characterized by Fourier-transform infrared spectroscopy, allowing the identification of functional groups present in the extract.

Tratamento de efluente têxtil :: processo físico-químico com ozônio e floculação em meio granular /

Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico.A cor dos efluentes têxteis se dá devido aos corantes utilizados no processamento têxtil. O presente trabalho investigou através de estudos em laboratório, o tratamento de efluentes têxteis através da floculação em meio granular expandido, dos efluentes bruto, pré-ozonizado, e pré-ozonizado tratado biologicamente. Como material de estudo, foi utilizado o efluente da Indústria Têxtil Damyller, situada no município de Nova Veneza

Potencial dos resíduos do processamento de camarão para remediação de águas contaminadas com drenagem ácida mineral

Resumo A drenagem ácida mineral (DAM) é um dos mais graves impactos ambientais da mineração. Cursos de água impactados pela DAM são avaliados como impróprios acarretando graves impactos ambientais e problemas socioeconômicos severos. Este estudo visa identificar o potencial de um resíduo, casca de camarão, como fonte de quitina e alcalinidade para remediação de águas contaminadas por DAM visando seu posterior reuso para fins secundários não potáveis. Foram efetuados ensaios com a casca de camarão, diferenciando entre corpo (CR) e cabeça (CB), e quitina comercial (QT, 70% de pureza), para o tratamento de amostras de água superficiais e subterrâneas impactadas da Região Carbonífera Catarinense/SC (Brasil). Realizaram-se ensaios em duplicata e em regime de batelada variando o teor de substrato, tempo de contato e velocidade de agitação. Conseguiu-se a remoção quase total de Fe (>92%) e Al (>99%) e uma remoção de Mn entre 40-60%. CR apresentou os melhores resultados após 48h de tratamento com 200 rpm e 10 gL–1de substrato. O aumento no pH foi mais significativo nas amostras contendo CR, passando o pH de ~3 para ~7. Os resultados indicaram o potencial da utilização direta da casca de camarão para o tratamento de efluentes para reuso secundário não potável

Processo UV/H2O2 como pós-tratamento para remoção de cor e polimento final em efluentes têxteis

Several problems are involved the treatment plants of textile effluents, mainly the low efficiency of color removal. This paper presents an alternative of post-treatment by UV/H2O2 process, for color removal in biologically treated textile effluents. The tests were performed in a photochemical reactor and samples were taken at different times to perform analyses. Using 250 mgH2O2.L-1, 96% removal of color was verified, indicating the dyes degradation. A reduction of 84% of aromatics compounds, 90% of TSS removal, and a further reduction of the organic fraction were observed, demonstrating that the process is effective as a post-treatment of effluents from textile industries

REMOVAL OF ORGANIC MATTER FROM WATER DISCARDED BY PAPER AND CELLULOSE MILLS AFTER UV/H2O2 TREATMENT

aper and cellulose mills effluents are composed by several combinations of chemical reagents used in productive stages and of substances originating from raw material, used to produce paper and cellulose pulp. Considering the volume of effluents generated by such industries and the current crisis of water  resources, it is blatant the need of an efficient treatment for the discarded water. The advanced oxidative processes constitute an attractive option for treating several effluents. They are capable of promoting degradation and even mineralization of refractory pollutant particles. The current paper looks forward to assessing the performance of the UV/H2O2 process in removing organic matter present in the effluent of a paper mill. The research was carried out in a photochemical reactor with active capacity of 1300 mL. As source of UV radiation, it was used a medium pressure mercury lamp of 125 W. During 120 minutes of UV irradiation, six H2O2 concentrations were testes, varying between 15 and 200 mg.L-1. The results revealed the effectiveness of the process when removing 84% of the CDO and 91% of the BOD5. The performance of the UV/H2O2 process was influenced by the availability of H2O2 and the time of UV irradiation