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Rapid technological development in recent decades has led to very high generation of waste electrical and electronic equipment, including exhausted nickel metal hydride batteries. Therefore, efficient and environmentally friendly recycling techniques are required for the recovery of the valuable materials of this type of waste. The aim of the present work was to develop an alternative process for recovery of the different materials present in these batteries, by means of mechanical processing with additional steps of size separation than the usual in the literature. Firstly, the batteries were manually disassembled, and the different components were separated and weighed. The components were then characterized by XRD, XRF, DSC and SEM–EDS analyses. After the characterization, mechanical processing was performed, involving the following steps: comminution in a hammer mill, oven-drying to eliminate the electrolytes, size separation by sieving, magnetic separation and two additional steps of size separation by sieving. The proposed process was shown to be highly efficient, achieving recovery efficiencies in the range of 86.54–91.25 wt.% for the different outputs obtained, with high degree of calculated purity attained as well (96.64–100.00 wt.%).

Recycling post-consumer packaging of high and linear/low-density polyethylene (HDPE, LDPE/LLDPE) and polypropylene (PP) (most representative in any plastic waste stream) is a viable alternative. However, these packages must be washed first, especially those with a high content of contaminants (such as yogurt—HDPE and margarine—PP). Therefore, this study aimed to develop a complete pre-treatment of polymeric wastes (HDPE, LDPE/LLDPE, PP) involving the steps of quantification, characterization, washing (pre-wash/ washing/rinsing), treatment of the generated effluent and the reuse of treated water in a closed circuit. Afterward, the qualification of recyclable material selectors was performed with associations/cooperatives of recyclable material in the Rio Grande do Sul, South region of Brazil. The results indicated that the subdivision in prewash/washing/rinsing utilizing sulfonic acid (1.16% v/v), lauryl (sodium lauryl ether sulfate) (0.53% v/v) and soda (0.31% v/v) was suitable for obtaining clean polymeric waste. Treatment of effluent using aluminum sulfate (4 g L−1) as a coagulant, followed by filtration, was efficient with removal values greater than 90%. These characteristics of treated water allowed its reutilization water of a safe way in closed circuit in the process of washing of the polymeric wastes. Finally, a total of sixty-four selectors of recyclable materials were trained and the theoretical–practical training was quite satisfactory for more than 95% of selectors. Therefore, it can be concluded that the great importance to transmitting the knowledge to society generated in this studies and thus provides best conditions for the development of these selectors of recyclable materials.

Wax obtained from the pyrolysis of polyethylene waste can contain inorganic contaminants and must be purified before application. We evaluated different filter aids (perlite, sand, and rice husk ash) for the filtration of a crude wax and a pyrolysis wax through a filter medium that was coated with nylon 6 nanofibers to improve filtration efficiency. We first examined the performance of the filter aids in improving crude wax filtration, with the filtration time, temperature, and pressure held constant at 1 h, 170 °C, and 2.5 bar, respectively. Oily wax was then produced by pyrolysis of high-density polyethylene (HDPE) waste in the temperature range 425⿿475 °C. The best filter aid was perlite, which had a filtrate production rate of 5.47 y 10⿿5 m3/h. The highest oily wax yield (87.8%) was achieved at a pyrolysis temperature of 425 °C. The assembly comprising the filter medium coated with nylon 6 nanofibers plus perlite as a filter aid was most suitable for removing impurities from the oily wax generated by the HDPE pyrolysis as it achieved a purification efficiency of 99.9%.

A falling film molecular distillation (FFMD) process was used in a pilot plant to fractionate a polyethylene wax (PE-Wax) into light paraffin wax (LP-Wax) and super-microcrystalline wax (SM-Wax). The pseudoization technique was applied to represent the molecular distribution of the PE-Wax by pseudo-components (PS1 and PS2). Investigation was made of the influences of the evaporator temperature (EVT), feed flow rate (FF), and condenser temperature (CT) on the percent recovery of distillate (DP), the yield of PS1 in the distillate ( Y D _ P S 1 ), and the distillate flow rate/feed flow rate ratio (DF). The predictive models and the multi-response optimization provided decision criteria about the most suitable operating conditions for fractionating PE-Wax. The best experimental data for DP, Y D _ P S 1 , and DF (63.4%, 81.5%, and 0.60, respectively) were obtained with EVT of 184 °C, FF of 1.81 kg/h, and CT of 28 °C, at 0.1 Pa. The LP-Wax, recovered mainly in the distillate, exhibited a normal distribution throughout the carbon number range from n-C13 to n-C30. The SM-Wax, recovered in the residue, showed a higher latent heat of storage (>169 kJ/kg), according to the phase-change performance of the material. These results offer new insights into processing PE-Wax to obtain value-added products with narrower carbon number distributions.

Cables and wires, which are essential parts of equipment for the transmission of both information and electricity, contain valuable materials including copper (Cu) and aluminum (Al). This experimental work evaluates the use of mechanical processing (grinding and sieving), followed by spouted bed elutriation, for separation of the valuable materials (steel-coated copper, copper, and aluminum) present in waste coaxial and internet cables. A recovery efficiency of approximately 90% was achieved for the steel-coated copper in coaxial cables. For internet cables, the copper recovery efficiency was approximately 87%. These findings demonstrate that it is possible to separate, recover, and recycle the valuable materials (metals) present in waste cables using simple, low-cost, and efficient mechanical processing followed by spouted bed elutriation.

The main objective of this work was to develop a nanomaterial able to selectively extract and recover indium (In) from obsolete cell phone LCD screens. For this, Nylon 6 nanofibers were produced and modified with di-(2-ethylhexyl)phosphoric acid (DEHPA) for application in the solid-phase extraction of In. The best extraction conditions for concentration of In were 30% DEHPA, pH 0.5, 7.5 min contact time, and S:L ratio of 1:300. In this step, an In extraction efficiency of around 74% was obtained. In stripping steps, an efficiency of 92% was achieved using 1.5 M HCl, S:L ratio of 1:20, and 5 min contact time. Under the best extraction and stripping conditions, it was possible to obtain up to 6-fold concentration of In, compared to the initial concentration. In addition, the nanofibers were evaluated in terms of their stability and capacity for reuse, which showed that there was no significant loss of DEHPA and that the extraction efficiency remained almost constant. The findings demonstrated the possibility of using the Nylon 6/DEHPA nanofibers in a highly efficient extraction/stripping procedure for the selective recovery of In and Sn, with reduced environmental impacts.

The aim of this work was to develop new materials employing polymeric nanofibers modified with an organic extractant for the extraction of metals. For this purpose, nylon-6 nanofibers were modified with di-(2-ethylhexyl) phosphoric acid (DEHPA) for use in the selective extraction of zinc and nickel. The best extraction efficiencies were 85.5% for Zn and 4.6% for Ni, achieved under the following conditions: pH 2, solid:liquid (S:L) ratio of 1:40, and contact time of 7.5 min. In the stripping, the best efficiencies were 85.9% for Zn and 90.1% for Ni, using a concentration of HCl of 0.5 M, S:L ratio of 1:10, and contact time of 5 min. The nanofibers were evaluated in terms of their stability and capacity for reuse, and it was found that there was no loss of the DEHPA extractant from the nanofibers, while the extraction efficiency remained almost constant. Regarding to environmental aspects of the new technology, the results confirm that nanofibers exhibit the same efficiency of conventional liquid-liquid extraction, without the disadvantage of the use of organic solvents. In this way, this new technology brings an enormous gain in environmental terms, since it drastically reduces the use of hazardous substances.

The objectives of this work were to develop polyacrylonitrile nanofibres modified with the commercial Cyanex 272 extractor and apply them for the recovery of gallium present in aqueous solution. The nanofibres were produced using the centrifugation technique, employing Forcespinning® equipment. The average nanofibre diameter ranged from 530 to 840 nm. The highest adsorption of gallium was achieved at pH 2.5, with a pseudo-second order kinetic model and the Freundlich equilibrium isotherm model providing the best fits of the experimental data. The thermodynamic parameters showed that the adsorption was spontaneous, favourable, and endothermic. The maximum capacity of the PAN/Cyanex 272 nanofibres for the recovery of gallium was 38.93 mg g

This work aims to perform a comparative study of two mechanical processes for the recycling of metals from coaxial cables (aluminium and copper-clad steel): Process I - comminution, sieving and electrostatic separation; and Process II - comminution, magnetic separation and electrostatic separation. Characterization techniques were performed on the cables to discover their composition. The parameters evaluated of electrostatic separation were: roll speed (

The presence of inorganic substances in the composition of crude wax decreases its commercial value, necessitating purification of the product. A new physical surface treatment for filter media involving the application of nanofibers of Nylon-6 polymer was developed using the Forcespinning® equipment. The performance of the nanofiber-coated filter was compared with the results obtained for other filter media of the same composition (nonwoven aramid fiber fabric), one without physical treatment, and another treated using singeing. An experimental design was carried out to find the optimum operating temperature and pressure (170 °C and 2.5 bar, respectively). The filtrate volume, specific resistance of the filter cake, and filter medium resistance were determined, keeping the filtration time, temperature, and pressure constant at 1 h, 170 °C, and 2.5 bar, respectively. The nanofiber-coated filter showed the best performance, providing a higher wax filtrate volume and greater retention of inorganics, with values of 5.39 × 10−5 m3 and 99.6%, respectively.

In this study, novel nanofiber materials composed of chitosan/nylon 6 and tannin/nylon 6 were synthesized by the Forcespinning® method and were used as adsorbents for effective removal of chromium(VI) from aqueous solutions. The nanofibers showed similar production rates of 3.5 g h−1. The diameters of the nanofibers ranged from 100 to 800 nm. Under the experimental conditions tested, chromium(VI) adsorption was favored at pH 3 (chitosan/nylon 6 nanofibers) and pH 2 (tannin/nylon 6 nanofibers), at a temperature of 328 K. The most suitable models for description of the kinetic data were the pseudo-second order model (chitosan/nylon 6 nanofibers) and the Elovich model (tannin/nylon 6 nanofibers). For both nanofibers, the equilibrium isotherms could be fitted by the Langmuir model. The maximum adsorption capacities were 23.9 and 62.7 mg g−1 for the chitosan/nylon 6 and tannin/nylon 6 nanofibers, respectively. The thermodynamic parameters showed that the adsorption was spontaneous, favorable, and endothermic. The findings indicated that these nanofibers produced using a centrifugal technique offer excellent potential as adsorbents, with high adsorption capacities for chromium(VI).

One of the greatest challenges in the development of hydrometallurgical processes for the recovery of indium from secondary sources is the fact that the leaching step generally results in very dilute solutions. Therefore, this diluted indium solution must be concentrated before being sent to a subsequent step such as recovery of the metal by electrowinning. The aim of the present work was to apply solvent extraction using bis(2-ethylhexyl) phosphate (D2EHPA) in order to maximize the indium concentration in the solution. Firstly, the extraction and stripping steps were investigated using a synthetic solution. After definition of the best conditions using a synthetic solution, a real solution obtained from the leaching of discarded LCDs was employed.

In the last decades, increasing industrial development has led to huge consumption of plastic materials, due to their versatility and low cost. Therefore, the implementation of efficient and environmentally friendly recycling technologies is of great importance. This study proposes an alternative separation process for recycling mixtures of plastic wastes, using a tribo-electrostatic separation process. The methodology adopted in this work was firstly characterization of the polymeric wastes, followed by preparation of the wastes using different unit operation processes (washing, drying, and comminution), tribo-charging, and electrostatic separation of different combinations of plastics (HDPE/PP, LDPE/PP, and PET/PVC). Various parameters were evaluated in the tribo-charging process and the electrostatic deflection. Separation of a mixture of HDPE and PP achieved PP recovery of 92.8% (purity of 95.7%) and HDPE recovery of 95.9% (purity of 93.1%). Recovery and purity values higher than 90.2% and 95.9% were obtained for PP/LDPE and PET/PVC mixtures, respectively. These results demonstrated that tribo-electrostatic separation is a promising and efficient method for use in the recycling of plastic wastes. The process studied enabled significant recoveries of the components at high levels of purity.

Continuing industrial development results in ever greater consumption of products and materials. These include electrical and electronic equipment (EEE) such as mobile phones and, consequently, lithium ion batteries (LIBs). Therefore, an efficient and environmentally friendly recycling technology is vital for the recovery of valuable materials from spent LIBs. This work describes an alternative process for the recovery of these materials, using mechanical processing and electrostatic separation. Firstly, the batteries are dismantled and their components are characterized. This is followed by comminution, drying (to remove the organic electrolyte), separation according to particle size, and electrostatic separation of the conductive and nonconductive parts of the LIBs. Parameters evaluated in the electrostatic separation were the electrode voltage, roll rotation speed, distance of the electrostatic electrode, and the inclination angle of the deflector. The results showed recovery of a conductive fraction containing 98.98% of metals and a nonconductive fraction containing 99.6% of polymers, demonstrating that electrostatic separation is a promising and efficient method for the recovery of high purity materials from spent LIBs.

The printed circuit boards are the fundamental components of waste electrical and electronic equipment (WEEE). The PCBs stand out due to the amount of metals in their composition as well for their complex and heterogeneous constitution that make their recycling difficult. In this context, the aims of the study was to evaluate the application of supercritical CO2 modified with ethanol in order to remove the polymers contained in PCBs from discarded mobile phones. The PCBs were characterized and an evaluation of the supercritical extraction was performed through experimental design. The characterization showed that PCBs contained 64.02 wt% of metals, 20.51 wt% of ceramics and 15.47 wt% of polymers. The fractional factorial experimental design showed that 69.53 wt% of the polymers present in the PCBs were extracted, at 170 °C and 7.5 MPa. As the remaining polymers are no longer covering the metals, they could be more easily leached and therefore more effectively recovered.

Chitosan/polyamide nanofibers (CP nanofibers) were prepared by a new Forcespinning® technology, and used as alternative adsorbent to remove Reactive Black 5 (RB5) and Ponceau 4R (P4R) dyes from aqueous solutions. The results demonstrated that under the best operational conditions (30 G½” needles, spinneret rotation of 12000 rpm for 10 min and chitosan polyamide ratio of 1.00/1.50), chitosan/polyamide nanofibers were produced at a rate of 3 g h−1. CP nanofibers presented a semi–crystalline structure, with several functional groups and diameter from 100 to 500 nm. The adsorption of RB5 and P4R on the CP nanofibers was favored at pH of 1.0. Pseudo–second order (RB5) and Elovich (P4R) models were the more adequate to represent the kinetic data. The equilibrium data followed the Langmuir model, being the maximum adsorption capacities of 456.9 mg g−1 for RB5 and 502.4 mg g−1 for P4R. The adsorption was spontaneous, favorable and endothermic. Desorption and reuse was possible for four times, maintaining the same adsorption capacity. In brief, it can be concluded that the Forcespinning® technology is an alternative to obtain chitosan/polyamide nanofibers with suitable characteristics. These nanofibers in turn, can be successfully applied to remove dyes from aqueous media.

The demand for photovoltaic panels has increased in recent years and the resources used in its production such as silicon, with high production costs and silver that is becoming scarce, in addition to the presence of toxic metals such as lead, highlight the importance of recycling of these materials. One of the main challenges for recycling is the delamination of the panels, for which supercritical fluids can be an effective option. Constituents of a photovoltaic module were analyzed using SEM/EDS, XRD, XRF, TGA, DSC, and FTIR techniques. The efficiency of the delamination process was evaluated using tests carried out at atmospheric pressure, in the presence of different cosolvents. Comparative tests were performed using supercritical CO2 (ScCO2). For both processes, after delamination, the components that still showed low release of adhered materials were processed in a planetary ball mill. Determinations were then made of the recovery and purity of the delaminated fractions, as well as the separation of the adhered materials. The best results for recovery and purity of the glass, metallic filaments, and backsheet were obtained using ScCO2 with toluene, together with planetary ball milling, achieving values over 96 %. For the solar cell and EVA (cell + EVA), the recovery was greater than 85 %, including high value materials such as Si and Ag. In addition to recovering high value metals and reducing the volume of solvent, the use of ScCO2 enabled delamination of the photovoltaic panel with a time around 3.5 times shorter than at atmospheric pressure.

The convective air drying of papaya seeds was studied in order to optimize the seed oil yield. Papaya seeds were dried under different conditions of air temperature and air velocity. The operation was characterized by drying rate and drying kinetic curves. Oil was extracted from the seeds, obtained in all drying conditions and, the yield was optimized. The results revealed that the constant rate and falling rate periods occurred during the convective air drying of papaya seeds. The Overhults kinetic model was suitable to represent the experimental drying curves. The optimal drying conditions, which provided the maximum seed oil yield, were: air temperature of 70 °C and air velocity of 2.0 m s−1. In these conditions, the seed oil yield was 19.23% and the final moisture content was 7.40% (w.b.). High quality oil, with about 90% of oleic acid, was obtained from papaya seeds.

Ultrasound-assisted (UA) and supercritical CO2 technologies (SCO2) were used to modify the chitin surface and, improve its adsorption characteristics regarding to cobalt. Chitin, before and after the treatments, was characterized by N2 adsorption isotherms (BET), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Unmodified and surface modified chitins were used as adsorbents to remove cobalt from aqueous solutions. The adsorption study was performed by equilibrium isotherms and kinetic curves. The chitin particle characteristics, such as, surface area, pore volume and porosity were improved by the UA and SCO2 treatments. The crystallinity index decreased after the UA and SCO2 treatments, and also, intense surface modifications were observed. Langmuir and Freundlich models were adequate to represent the adsorption equilibrium. The maximum adsorption capacities were 50.03, 83.94 and 63.08 mg g(-1) for unmodified chitin, UA surface modified chitin and SCO2 surface modified chitin. The adsorption kinetic curves were well represented by the pseudo-second order model. UA and SCO2 technologies are alternatives to modify the chitin surface and improve its adsorption characteristics.

Zinc aluminate (ZnAl2O4) particles with a spinel structure were prepared by metal-chitosan complexation method. The solids were obtained by the thermal decomposition of precursor compound of metallic hydroxides mixture and the biopolymer chitosan. X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and N2-adsorption–desorption isotherms were used for the characterization of the products. The results showed that the ZnAl2O4 spinel can be obtained by heating the precursor at temperatures above of 500 °C, resulting in a material with porous structure and large surface area and high purity.

The processing of papaya generates a significant amount of solid wastes. The seeds represent a significant amount and a source of untapped products. Papaya seeds have useful compounds, which can be obtained from its extracts or oils and can be a very effective biosorbent. For good results in the compounds achievement and the pretreatment, it is essential the appropriated choice of the drying conditions. This article proposes the study of the drying of papaya seeds in a tunnel dryer at three drying temperatures (40, 70, and 100°C) and three air drying velocities (1.0, 1.5, and 2.0 m · s−1). Empirical and semi-empirical models were proposed to adjust the kinetic parameter as a function of the drying conditions. The particle swarm optimization method was used, obtaining, as a result, an exponential model with good prediction quality and with few parameters to be adjusted.

This work investigates the use of leaching with malic and citric acids for the recovery of neodymium (Nd) from the NdFeB permanent magnets of discarded hard disk drives (HDDs). Evaluation was made of the effect of previous roasting of NdFeB powder on the recovery of Nd. The HDDs were manually disassembled and the magnets were removed, demagnetized, and comminuted. The roasted NdFeB powder was produced by heating in a muffle furnace at 900 °C for 480 min, resulting in complete transformation of the metals into their oxides. Evaluation was made of the effects of the following leaching parameters: temperature (30–90 °C), acid concentration (0.2–1.2 M), solid:liquid ratio (1:10–1:50), and leaching time (10–900 min). For both organic acids, the best values for the first three parameters were 90 °C, 1.0 M, and 1:20. Using malic acid, the best leaching time for the unroasted NdFeB powder was 360 min, which resulted in 99% recovery of Nd. Leaching with citric acid showed good efficiency up to 60 min, with 72.8% recovery of Nd. However, for longer times, complexation between Fe and citrate led to the formation of a thick sludge, which prevented continuation of the leach. Leaching of the unroasted NdFeB powder resulted in low selectivity between Nd and Fe. In the case of the roasted NdFeB powder, the Nd recovery efficiencies achieved using malic acid and citric acid were 22% and 32.1%, respectively. However, high selectivity was obtained, with 86.0% and 98.0% Nd, relative to Fe, using malic acid and citric acid, respectively.

CuO/ZnO coupled oxide films were electrodeposited onto an aluminum substrate and tested as photocatalysts in degradation of phenol molecules in aqueous solution under sunlight. The obtained films were characterized by X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results showed that the photocatalytic activity of films was significant, especially to coupled oxide film with a CuO/ZnO ratio equal to 0.697, which presented about 70% degradation of the aromatic molecules and 42% of total organic carbon (TOC) removal at 300 min under solar irradiation. Therefore, this work highlights the potential application of CuO/ZnO coupled oxide films obtained by electrodeposition onto aluminum substrate in the field of photocatalysis.

The study of conducting polymeric membranes is decisive in some areas, as in fuel cells and electrodialysis. This work aims the study of membranes using conventional and conductive polymers blends. Two types of polyurethane were used as conventional polymers, commercial thermoplastic polyurethane and polyurethane synthesized from castor oil and 4-4-dicyclohexylmethane isocyanate. Two kinds of conducting polymers were used, polyaniline doped with organic acid and a self doped polyaniline. The polymers and the membranes were characterized by electrical conductivity, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). The synthesis of the membranes produced was proper, featuring a complete reaction, analyzed by FTIR. The membranes also showed good mechanical properties and thermal stability (≈ 220 °C). Among the membranes studied, the polyaniline doped with p-toluenesulphonic acid obtained higher thermal and viscoelastic properties. Thus they can be used in separation techniques using membranes.

For nickel and cobalt recovery from spent NiMH batteries by electrowinning, the effect of different electrowinning parameters as boric acid concentration, temperature, current density, and pH were studied using different synthetic solutions. The optimized operational parameters were applied in an electrowinning test with a solution achieved by leaching the electrodes of NiMH batteries. The electrowinning tests were performed galvanostatically in a two-compartment cell separated by an anionic membrane. A platinum/iridium-coated titanium anode and a stainless-steel cathode were used. A sodium sulfate solution served as anolyte. The results demonstrate the technical viability of nickel and cobalt recovery. The chemical composition of the obtained deposit presented high nickel and cobalt concentrations.

In this study, different membranes were prepared using conventional polymer (high impact polystyrene) and polyaniline to evaluate their use in electrodialysis. Two different preparation modes were tested: chemical mixture with subsequent solvent evaporation; and mechanical mixture with subsequent pressing under heating. The purpose was to understand the effect of production methods on membrane microstructure and ionic transport. Membranes were characterized by swelling study, Fourier transformed infrared spectroscopic, scanning electron microscopy, thermogravimetric analysis and dynamic mechanical analysis. Ionic transport through the membranes was evaluated using a three-compartment cell. The results of the produced membranes were compared with those of the commercial Nafion 450 membrane.

Technological development and intensive marketing support the growth in demand for electrical and electronic equipment (EEE), for which printed circuit boards (PCBs) are vital components. As these devices become obsolete after short periods, waste PCBs present a problem and require recycling. PCBs are composed of ceramics, polymers, and metals, particularly Cu, which is present in highest percentages. The aim of this study was to develop an innovative method to recover Cu from the PCBs of old mobile phones, obtaining faster reaction kinetics by means of leaching with supercritical CO2 and co-solvents. The PCBs from waste mobile phones were characterized, and evaluation was made of the reaction kinetics during leaching at atmospheric pressure and using supercritical CO2 with H2O2 and H2SO4 as co-solvents. The results showed that the PCBs contained 34.83 wt% of Cu. It was found that the supercritical extraction was 9 times faster, compared to atmospheric pressure extraction. After 20 min of supercritical leaching, approximately 90% of the Cu contained in the PCB was extracted using a 1:20 solid:liquid ratio and 20% of H2O2 and H2SO4 (2.5 M). These results demonstrate the efficiency of the process. Therefore the supercritical CO2 employment in the PCBs recycling is a promising alternative and the CO2 is environmentally acceptable and reusable.

The great technological development leads to a large consumption of electronic products. The electronics are increasingly becoming obsolete and faster discarded, often without adequate treatment, contaminating water, soil and air by being exposed to the environment. Among these products are the mobile phones which have as a major component the LCD panel (Liquid Crystal Display). The LCD panel consists of multilayers of different materials, some with high added value, such as indium tin oxide (ITO). The presence of noble materials in the composition of this type of residue makes its recovery profitable. The objective of this study is to characterize and separate the different materials that constitute the LCD panels of cell phones into disuse. Initially, the different materials that form the panels are manually separated such as adhesives, diffusive sheets , reflective sheets, connectors, polarizing film, plastic frame and the glass panel with ITO. The polarizing film that adheres to glass was removed through a bath of solvent. Then, we performed a milling of the screen in a knives mill. In this milling process were used screens containing polarizing film and screens without the film, in order to obtain a uniform particle size aiming the recovery of the elements present. With these procedures the mass ratio of each material present in the cellular LCD panels was obtained, as well as a material with low particle size, suitable to undergo to a hydrometallurgical processes.

The metal-finishing and tannery industries have been under strong pressure to replace their current wastewater treatment based on a physicochemical process. The electrodialysis process is becoming an interesting alternative for wastewater treatment. Electrodialysis is a membrane separation technique, in which ions are transported from one solution to another through ion-exchange membranes, using an electric field as the driving force. Blends of polystyrene and polyaniline were obtained in order to produce membranes for electrodialysis. The produced membranes were applied in the recovery of baths from the metal-finishing and tannery industries. The parameter for electrodialysis evaluation was the percentage of chromium extraction. The results obtained using these membranes were compared to those obtained with the commercial membrane Nafion 450.

The growing environmental concern, associated with the continuous increase in electronic equipment production, has induced the development of new technologies to recycle the large number of spent batteries generated in recent years. The amount of spent lithium–ion batteries (LIBs) tends to grow over the next years. These batteries are composed by valuable metals, such as Li, Co, Cu and Al, which can be recovered. Thus, the present work is carried out in two main steps: In the first step, a characterization of the LIBs is performed. Batteries from different brands and models are dismantled and their components characterized regarding to the chemical composition and main phases. In the second step, a sample of LIBs is shredded and the different materials present are separated by spouted bed elutriation. The results show that spouted bed elutriation is a simple and inexpensive way to obtain the separation of the different materials (polymers, metals, active electrode materials) present in spent LIBs.