Showing papers by "Andréa Moura Bernardes published in 2015"

Electronic Waste: Generation and Management

Abstract: The electronics industry is one of the most important industries in the world. It has grown steadily in recent decades, generates a great number of jobs, promotes technological development and, at the same time, fuels a high demand for raw materials that are considered scarce or rare (e.g. precious metals and rare earths elements).

Current-voltage curves for treating effluent containing HEDP : determination of the limiting current

Abstract: Membrane separation techniques have been explored for treating industrial effluents to allow water reuse and component recovery. In an electrodialysis system, concentration polarization causes undesirable alterations in the ionic transportation mechanism. The graphic construction of the current voltage curve is proposed for establishing the value of the limiting current density applied to the cell. The aim of this work was to determine the limiting current density in an electrodialysis bench stack, the function of which was the treatment of an electroplating effluent containing HEDP. For this, a system with five compartments was used with a working solution simulating the rinse waters of HEDP-based baths. The results demonstrated correlation between the regions defined by theory and the experimental data.

Leaching of gold and silver from printed circuit board of mobile phones

Abstract: Nowadays there is a wide variety of models, sizes and configurations of mobile phones available for consumption. After the life cycle of this equipment, the recycling and reuse of the precious metals found in the printed circuit boards (PCB) of the mobile phones are principal objectives. Thus, the objective of this work was to characterize the gold and silver present in a PCB and develop a recycling route using alternative reagents for cyanide, such as sodium and ammonium thiosulfate. These reagents are less harmful to the environment and worker health. The first characterization of gold and silver was performed with aqua regia. The results show 86.26g Au/ton of PCBs and 123.85g Ag/ton of PCBs. The second characterization was performed with a commercial cyanide-based reagent and 112.02g Au/ton of PCBs and 26.13g Ag/ ton of PCBs were obtained. A leaching study with solutions based on thiosulfate was performed and an extraction of 9.02g Au/ton of PCBs and 33.88g Ag/ton of PCBs was obtained, compared to characterization results using a cyanide-based reagent.

Integration of membrane bioreactor and advanced oxidation processes for water recovery in leather industry

Abstract: Nowadays, the conventional tannery wastewater treatment is not established in order to obtain water in such a quality that it could be reused in the same process This study was then carried out in order to study an integrated wastewater treatment system, membrane bioreactor–photoelectrooxidation (MBR–PEO), for the final polishing of tannery wastewater MBR is responsible for the remaining biochemical oxygen demand removal, while the refractory matter, quantified as chemical oxygen demand, is removed by PEO This treatment configuration has provided two wastewater streams with quality standards for reuse as process water The wastewater treated by the MBR could be reused in beamhouse operations, while the wastewater treated by the integrated MBR–PEO processes could be recycled for the tanyard and re-tanning steps due to its appreciable quality

Toxicity effects of nickel electroplating effluents treated by photoelectrooxidation in the industries of the Sinos River Basin

Abstract: The Sinos river Basin is an industrial region with many tanneries and electroplating plants in southern Brazil. The wastewater generated by electroplating contains high loads of salts and metals that have to be treated before discharge. After conventional treatment, this study applied an advanced oxidative process to degrade organic additives in the electroplating bright nickel baths effluent. Synthetic rinsing water was submitted to physical-chemical coagulation for nickel removal. The sample was submitted to ecotoxicity tests, and the effluent was treated by photoelectrooxidation (PEO). The effects of current density and treatment time were evaluated. The concentration of total organic carbon (TOC) was 38% lower. The toxicity tests of the effluent treated using PEO revealed that the organic additives were partially degraded and the concentration that is toxic for test organisms was reduced.

Membrane separation processes applied to the treatment of effluents from nanoceramic coating operations

Abstract: In this work, the use of membrane separation processes (MSP) for the treatment of a synthetic effluent from a nanoceramic coating line was evaluated. Three MSP were tested: electrodialysis, microfiltration, and nanofiltration (NF). The presence of zirconium, a chemical element able to combine with different compounds producing complexes, and pH variations in the nanoceramic effluent are responsible for the different efficiency levels of the MSP in treating this effluent. The better results were reached with NF, making this process an option for the treatment of this new effluent.

Degradation and inactivation of adenovirus in water by photo-electro-oxidation

Abstract: The present study analyzed the efficiency of the photo-electro-oxidation process as a method for degradation and inactivation of adenovirus in water. The experimental design employed a solution prepared from sterile water containing 5.107 genomic copies/L (gc/L) of a standard strain of human adenovirus type 5 (HAdV-5) divided into two equal parts, one to serve as control and one treated by photo-electro-oxidation (PEO) for 3 hours and with a 5A current. Samples collected throughout the exposure process were analyzed by real-time polymerase chain reaction (qPCR) for viral genome identification and quantitation. Prior to gene extraction, a parallel DNAse treatment step was carried out to assess the integrity of viral particles. Integrated cell culture (ICC) analyses assessed the viability of infection in a cell culture. The tested process proved effective for viral degradation, with a 7 log10 reduction in viral load after 60 minutes of treatment. The DNAse-treated samples exhibited complete reduction of viral load after a 75 minute exposure to the process, and ICC analyses showed completely non-viable viral particles at 30 minutes of treatment.

Sustainable Manufacturing: The Lean and Green Business Model

Abstract: Over the past few years there has been an emergent trend towards integrating a lean and green approach with a number of papers and books written, but most of these take an outside-in approach describing case studies from industry. This paper differs in that it takes an inside-out approach; describing a Lean and Green Business Model (L&GBM) developed within a major global engineering company. It describes the five key principles of a Lean and Green Business Model, (i) a stable value stream, (ii) identification of environmental impacts, (iii) measurement the environmental value streams, (iv) improvement of the environmental value streams and (v) continuous improvement. It further explains how the model applies a Kaizen approach for improving mass and energy flows of manufacturing environment that already possesses a basic deployment level in applying lean. Some of the key findings identified by the researchers highlight that (i) L&GBM has a different purpose than traditional Lean or Environmental Thinking, (ii) L&GBM covers the three dimensions of sustainability, (iii) L&GBM has a Lean to Green approach and (iv) L&GBM is an alternative approach to integrate environmental concerns into operations management which enhances workplace engagement in reducing the environmental impact of the manufacturing processes by leveraging the lean attributes of involvement and empowerment to the environmental functions within the organization that traditionally have focused on compliance.

Degradation of cyanotoxins (microcystin) in drinking water using photoelectrooxidation

Abstract: The discharge of sewage and industrial effluents containing high concentrations of pollutants in water bodies increases eutrophication. Cyanobacteria, some of the organisms whose growth is promoted by high nutrient concentrations, are resistant and produce several types of toxins, known as cyanotoxins, highly harmful to human beings. Current water treatment systems for the public water supply are not efficient in degradation of toxins. Advanced oxidation processes (AOP) have been tested for the removal of cyanotoxins, and the results have been positive. This study examines the application of photoelectrooxidation in the degradation of cyanotoxins (microcystins). The performance of the oxidative processes involved was evaluated separately: Photocatalysis, Electrolysis and Photoelectrooxidation. Results showed that the electrical current and UV radiation were directly associated with toxin degradation. The PEO system is efficient in removing cyanotoxins, and the reduction rate reached 99%. The final concentration of toxin was less than 1 µg/L of microcystin in the treated solution.