Potencialidade do tratamento eletroquímico oxidativo associado à adsorção para remediação de corantes têxteis

This study aimed to evaluate the potential of oxidative electrochemical treatment coupled with adsorption process using expanded perlite as adsorbent in the removal of textile dyes, Red Remazol and Novacron Blue on synthetic effluent. Dyes and perlite were characterized by thermogravimetry techniques (TG), Differential Scanning Calorimetry (DSC), Spectroscopy infrared (IR), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. Electrochemical treatments used as anodes, Ti/Pt and Pb/PbO2 under different conditions: 60 minutes, current density 20, 40 e 60 mAcm-2, pH 1, 4.5 e 8 and temperature variation 20, 40 e 60 ºC. In the case of adsorption tests, contact time of 30 minutes for the Remazol Red dye and 20 minutes for Novacron Blue were established, while pH 1, 4.5 e 8, 500 mg adsorbent and temperature variation 20, 40 e 60 ºC were used for both treatments. The results indicated that both treatments, electroxidation/adsorption and the adsorption/electroxidation, were effective for removing color from synthetic solutions. The consumption of electricity allowed to evaluate the applicability of the electrochemical process, providing very acceptable values, which allowed us to estimate the cost. Total organic carbon (TOC) and Gas Chromatography linked mass spectrometer (GC-MS) analyzes were performed, showing that the better combination for removing organic matter is by Pb/PbO2 and perlite. Meanwhile, GC-MS indicated that the by-products formed are benzoic acid, phthalic acid, thiocarbamic acid, benzene, chlorobenzene, phenol-2-ethyl and naphthalene when Remazol Red was degraded. Conversely, aniline, phthalic acid, 1, 6 - dimethylnaphthalene, naphthalene and ion hidroxobenzenosulfonat was detected when Novacron Blue was studied. Analyses obtained through atomic absorption spectrometry showed that there was release of lead in the electrochemical oxidation of analyzes that were performed with the anode Pb/PbO2, but these values are reduced by subjecting the effluent to adsorption analysis. According to these results, sequential techniques electroxidation/adsorption and adsorption/electroxidation are to treat solutions containing dyes.

Adsorção de Pb(II) utilizando adsorvente composto por montmorilonita e dolomita

The destructive impact of improper disposal of heavy metals in the environment increases as a direct result of population explosion, urbanization and industrial expansion and technological developments. Argil are potential materials for adsorption of inorganic and the pelletization of it is required for use in adsorptive columns of fixed bed. The low cost and the possibility of regeneration makes these materials attractive for use in the purification process, capable of removing inorganic compounds in contaminated aquatic environments. In this work was made pellets of a mixture of dolomite and montmorillonite by wet agglomeration, in different percentages. The removal of Pb (II) was investigated through experimental studies, and was modeled by kinetic models and isotherms of adsorption. The materials were characterized using the techniques of XRD, TG / DTA, FT-IR, and surface area by BET method. The results showed the adsorption efficiency of the contaminant by the composite material studied in synthetic solution. The study found that the adsorption follows the Langmuir model, and the kinetics of adsorption follows the model of pseudosecond order

Adsorção de cobre e cromo utilizando fibra de sisal visando o tratamento da água produzida pela indústria petrolífera

Currently, the oil industry is the biggest cause of environmental pollution. The objective was to reduce the concentration of copper and chromium in the water produced by the oil industry. It was used as adsorbent natural sisal fiber Agave sp treated with nitric acid and sodium hydroxide. All vegetable fibers have physical and morphological properties that enablies the adsorption of pollutants. The basic composition of sisal is cellulose, hemicellulose and lignin. The features are typically found in the characterization of vegetable fibers, except the surface area that was practically zero. In the first stage of adsorption, it was evaluated the effect of temperature and time skeeking to optimize the execution of the factorial design. The results showed that the most feasible fiber was the one treated with acid in five hours (30°C). The second phase was a factorial design, using acid and five hours, this time was it determined in the first phase. The tests were conducted following the experimental design and the results were analyzed by statistical methods in order to optimize the main parameters that influence the process: pH, concentration (mol / L) and fiber mass/ metal solution volume. The volume / mass ratio factor showed significant interference in the adsorption process of chromium and copper. The results obtained after optimization showed that the highest percentages of extraction (98%) were obtained on the following operating conditions: pH: 5-6, Concentration: 100 ppm and mass/ volume: 1 gram of fiber/50mL solution. The results showed that the adsorption process was efficient to remove chromium and copper using sisal fibers, however, requiring further studies to optimize the process.

Projeto, construção e análise de um prototipo vibracional em escala de bancada aplicável ao tratamento de água de produção de petróleo bruto, mediante inovadora operação híbrida de adsorção e auto-flotação

A self-flotator vibrational prototype electromechanical drive for treatment of oil and water emulsion or like emulsion is presented and evaluated. Oil production and refining to obtain derivatives is carried out under arrangements technically referred to as on-shore and off-shore, ie, on the continent and in the sea. In Brazil 80 % of the petroleum production is taken at sea and area of deployment and it cost scale are worrisome. It is associated, oily water production on a large scale, carrier 95% of the potential pollutant of activity whose final destination is the environment medium, terrestrial or maritime. Although diversified set of techniques and water treatment systems are in use or research, we propose an innovative system that operates in a sustainable way without chemical additives, for the good of the ecosystem. Labyrinth adsor-bent is used in metal spirals, and laboratory scale flow. Equipment and process patents are claimed. Treatments were performed at different flow rates and bands often monitored with control systems, some built, other bought for this purpose. Measurements of the levels of oil and grease (OGC) of efluents treaty remained within the range of legal framework under test conditions. Adsorbents were weighed before and after treatment for obtaining oil impregna-tion, the performance goal of vibratory action and treatment as a whole. Treatment technolo-gies in course are referenced, to compare performance, qualitatively and quantitatively. The vibration energy consumption is faced with and without conventional flotation and self-flotation. There are good prospects for the proposed, especially in reducing the residence time, by capillary action system. The impregnation dimensionless parameter was created and confronted with consecrated dimensionless parameters, on the vibrational version, such as Weber number and Froude number in quadratic form, referred to as vibrational criticality. Re-sults suggest limits to the vibration intensity