Environmental impact assessment of different end-of-life LCD management strategies

Photochemical behaviour and toxicity evolution of phenylbenzoate liquid crystal monomers in water

Liquid crystal monomers (LCMs) are a group of emerging pollutants that pose potential environmental risks because of their ubiquitous occurrence and toxicity. Understanding their environmental transformation is essential for assessing the ecological risk. In this study, we investigated the photochemical transformation kinetics, mechanism, and photo-induced toxicity of three phenylbenzoate LCMs in water. Their apparent photolytic rate constants were within (0.023 - 0.058) min-1, and the half-lives were < 30.0 min, showing lower persistence in water. Dissolved organic matter significantly inhibited their photolysis because of light-shielding effect and quenching of excited triplet states of LCMs. Their photolysis mainly occurred through excited triplet states, and the reactive oxygen species (i.e., ⋅OH, 1O2 and ⋅O2-) contributed to their degradation. The main photolysis pathways were ester bond cleavage, ⋅OH substitution/addition, and defluorination. Experiments and computational simulation revealed that some ·OH addition/substitution products have similar toxicity with LCMs. Additionally, the ∙OH reaction rate constants (kOH) of LCMs were determined to be > 1 × 109 M-1 s-1, evidence for their high reactivity toward ⋅OH. We have further developed reliable methods to estimate kOH of other phenylbenzoate-like LCMs with quantum chemical calculations. These results are useful for understanding the transformation and fate of LCMs in aquatic environments.

Environmental Impact Assessment of Different Strategies for the Remanufacturing of User Electronics

Over the years, the innovation and development of electrical and electronic equipment have been on a steep rise. Millions of electronics are being sold or discarded every year in the form of waste. Sustainable IT (Green IT or Circular Computing) is one of the most environment-friendly methods of reusing discarded or waste user electronics. The remanufacturing of a computer refers to the disassembly, repair, and upgrade of the original computer to give it a new life, along with a warranty that is as good as a new product. The goal of this work includes studying and assessing the total environmental impact of refurbishing a computer using life cycle assessment (LCA) integrated with discrete event simulation (DES), to compare two business models: (1) a case of centralized remanufacturing where the plants are in the Middle East, which is the hub for receiving waste electronics and distributing remanufactured goods; (2) a case of decentralized remanufacturing where the plants are situated in each continent for over a range of computer models. The environmental assessment was conducted using the openLCA software in combination with the WITNESS Horizon software for the DES. The results show that decentralized remanufacturing is a much more environmentally friendly option for the remanufacturing of computers, and the decentralized remanufacturing operation has a better throughput as well as efficiency, as compared to the centralized remanufacturing operation. The centralized remanufacturing scenario has a climate change impact of 1035.19 kg of CO2-Eq, as compared to the decentralized remanufacturing scenario with an impact of 816.12 kg of CO2-Eq. In terms of the impact on the marine life, decentralized remanufacturing was found to have 0.28 kg of N-Eq impact, as compared to centralized remanufacturing (0.22 kg of N-Eq). However, this does not give us a complete picture, as the environmental impact of the computer in its previous life remains unknown. Multi life cycle assessment is the assessment process that can be used to get a clearer picture of the ecological footprint of the computer during its multiple life cycles.

Atmospheric persistence and toxicity evolution for fluorinated biphenylethyne liquid crystal monomers unveiled by in silico methods

It is essential to understand the atmospheric fate of liquid crystal monomers (LCMs), an important component in liquid crystal displays (LCDs); however, limited information is available at present. In this study, the atmospheric reaction mechanism, kinetics and toxicity evolution of three fluorinated biphenylethyne LCMs (1,2,3-trifluoro-5-(2-(4-methylphenyl)ethynyl)benzene (m-TEB), 1,2,3-trifluoro-5-(2-(4-ethylphenyl)ethynyl)benzene (e-TEB), 1,2,3-trifluoro-5-(2-(4-propylphenyl)ethynyl)benzene (p-TEB)) are investigated by theoretical calculations. Results show that the initial reactions of·OH addition to -C ≡ C- groups and hydrogen abstraction from alkyl groups (-CH₃, -C₂H₅, -C₃H₇) are dominant pathways. The resulting transformation products (TPs) for m-TEB are mainly highly oxidized multi-functional compounds such as benzil-based compounds, benzoic acid, alcohols, aldehydes, diketone and epoxy compounds. Results also show that some TPs exhibit higher aquatic toxicity than the parent. The calculated rate constants of m-TEB, e-TEB and p-TEB with·OH at 298 K are in the ranges of (1.3 -8.6) × 10^-12 cm³ molecule^-1 s^-1, and the corresponding atmospheric half-lives are 3.8-9.3, 2.2-5.4 and 0.6-1.4 days, respectively. This evidences that m-TEB and e-TEB may have atmospheric persistence and could undergo long-range transport. The results herein could be helpful for clarifying the atmospheric fates, persistence and risks of fluorinated LCMs with ethynyl benzene center.

About the environmental sustainability of the European management of WEEE plastics

A huge increase of waste of electrical and electronic equipment (WEEE) is observing everywhere in the world. Plastic component in this waste is more than 20% of the total and allows important environmental advantages if well treated and recycled. The resource recovery from WEEE plastics is characterised by technical difficulties and environmental concerns, mainly related to the waste composition (several engineering polymers, most of which containing heavy metals, additives and brominated flame retardants) and the common utilisation of sub-standard treatments for exported waste. An attributional Life Cycle Assessment quantifies the environmental performances of available management processes for WEEE plastics, those in compliance with the European Directives and the so-called substandard treatments. The results highlight the awful negative contributions of waste exportation and associated improper treatments, and the poor sustainability of the current management scheme. The ideal scenario of complete compliance with European Directives is the only one with an almost negligible effect on the environment, but it is far away from the reality. The analysed real scenarios have strongly negative effects, which become dramatic when exportation outside Europe is included in the waste management scheme. The largely adopted options of uncontrolled open burning and illegal open dumping produce huge impacts in terms of carcinogens (3.5·10⁺⁷ and 3.6·10⁺⁴ person⋅year, respectively) and non-carcinogens (1.7·10⁺⁸ and 2.0·10⁺⁶ person⋅year) potentials, which overwhelm all the other potential impacts. The study quantifies the necessity of strong reductions of WEEE plastics exportation and accurate monitoring of the quality of extra-Europe infrastructures that receive the waste.

Leaching of indium and tin from waste LCD by a time-efficient method assisted planetary high energy ball milling

The phenomenon of the long leaching time and low leaching rate is presented in the acid leaching process under the conventional conditions of low reaction temperature and acid concentration. In order to promote leaching rates of indium and tin in waste liquid crystal display, an optimized process combining rapid milling and acid leaching has been proposed, which is more time and energy-efficient, environmentally sound compared with the traditional acid leaching process. Leaching mechanism analysis was conducted to uncover the different leaching behavior of indium and tin. And the external factors affecting the leaching rates of indium and tin were studied to optimize. In this process, the fine powder with a weight ratio of 97.6%, which particle size less than 0.075 mm, was obtained with the optimal milling time of 30 min by rapid grinding in the planetary high energy ball milling. About -0.003 l/s of grinding rate constant was performed in the grinding size fraction from 3 mm to 0.075 mm. The research results indicated that the particle size less than 0.035 mm was agglomerated, and the addition of H₂O₂ reduced the leaching rate for the particle size less than 0.075 mm. Moreover, 86.3% and 76.1% of indium and tin were leached in a short leaching time of 10 min by using 3 M H₂SO₄ at 85 °C for particle size range from 0.075 to 0.035 mm, while 96.9% and 85.6%, respectively in 90 min.

Dispersion-free extraction of In(III) from HCl solutions using a supported liquid membrane containing the HA324H+Cl- ionic liquid as the carrier

By reaction of HCl and the tertiary amine HA324, an ionic liquid denoted HA324H⁺Cl⁻ was generated and used in the transport of indium(III) from HCl solutions. Metal transport experiments were carried out with a supported liquid membrane, and several variables affecting the permeation of indium(III) across the membrane were tested: stirring speed, metal and acid concentrations in the feed solutions and the carrier concentration in the supported organic solution. The metal transport results were also compared with those obtained using different carriers in the solid support. A model that described indium(III) transport across the membrane was proposed, and the corresponding diffusional parameters were estimated.

Indium tin oxide recycling from waste colour filter glass via thermal decomposition

Thermal decomposition was used to enrich indium tin oxide (ITO) from waste colour filter glass. The colour layer was destroyed through oxidation, and the ITO layer was separated from the glass substrate. With the increase in the temperature and time of thermal decomposition, the yield of ITO concentrate decreased, but the ITO recovery and enrichment ratio increased. Furthermore, the ITO could be effectively enriched at 600 °C and 8 min, where the yield, recovery and enrichment ratio of ITO were 0.06 %, 98 % and 1669, respectively. The particle size distribution of the ITO concentrate was mainly distributed in 0.1-1.3 and 2.6-42.0 μm, with cumulative percentages of 4.33 % and 95.55 %, respectively. Moreover, the crystal structure of recycled ITO was not changed. Substantial poisonous and harmful mixed flue gas are produced during thermal decomposition. After condensation and adsorption by activated carbon, the emission of mixed flue gas could be effectively controlled to avoid serious pollution to the atmospheric environment.

Discrete-Point Analysis of the Energy Demand of Primary versus Secondary Metal Production

The metal industry consumes large amounts of energy and contributes significantly, up to 10%, to global greenhouse gas (GHG) emissions. Recycling is commonly included among the most viable options for mitigating the climate forcing of metal production by replacing primary production. However, the recycling rates of metals are still incomplete and, in particular, do not exist for most specialty metals. Our empirical analysis of 48 metals shows that their recycling is mainly impeded by their low concentrations. In many cases, the metal concentration in end-of-life products is lower than that in natural ores. This phenomenon inevitably raises the question of the extent to which recycling can be conducted without losing its mitigating effects on climate change. We answer this question for two example metals, tantalum and copper, within the scope of Germany, a leader in recycling. For tantalum, the results show that a further increase in the end-of-life recycling rate (EOL-RR) could contribute to minimizing the overall energy consumption and GHG emissions, despite its low concentrations in end-of-life products. The energy requirements for recycling copper from end-of-life products already reach the magnitude of those for primary production. A further increase in EOL-RR must be examined in detail to ensure mitigating effects on climate change.

Adsorption of indium by waste biomass of brown alga Ascophyllum nodosum

The biosorption capacities of dried meal and a waste product from the processing for biostimulant extract of Ascophyllum nodosum were evaluated as candidates for low-cost, effective biomaterials for the recovery of indium(III). The use of indium has significantly grown in the last decade, because of its utilization in hi-tech. Two formats were evaluated as biosorbents: waste-biomass, a residue derived from the alkaline extraction of a commercial, biostimulant product, and natural-biomass which was harvested, dried and milled as a commercial, "kelp meal" product. Two systems have been evaluated: ideal system with indium only, and double metal-system with indium and iron, where two different levels of iron were investigated. For both systems, the indium biosorption by the brown algal biomass was found to be pH-dependent, with an optimum at pH3. In the ideal system, indium adsorption was higher (maximum adsorptions of 48 mg/g for the processed, waste biomass and 63 mg/g for the natural biomass), than in the double metal-system where the maximum adsorption was with iron at 0.07 g/L. Good values of indium adsorption were demonstrated in both the ideal and double systems: there was competition between the iron and indium ions for the binding sites available in the A. nodosum-derived materials. Data suggested that the processed, waste biomass of the algae, could be a good biosorbent for its indium absorption properties. This had the double advantages of both recovery of indium (high economic importance), and also definition of a virtuous circular economic innovative strategy, whereby a waste becomes a valuable resource.

Use and assessment of "e-plastics" as recycled aggregates in cement mortar

In this study we investigated the physical and mechanical properties of cement mortars, partially replaced with plastic (recycled plastic aggregate, RPA) recovered from WEEE (namely, "e-plastics"). The plastic housing of 14 LCD screens was sampled and, subsequently, compositionally and elementally analysed. Acrylonitrile-butadiene-styrene (ABS), being the most commonly found polymer in WEEE, was used as aggregate in the cement mortar. The replacement percentages (RPs) used were 2.5%, 5%, 7.5%, 10% and 12.5%, while the water to cement (w/c) ratio was maintained constant at 0.5 in all tests. The basic properties (e.g. compressive strength (CS), modulus of elasticity (MoE), density (ρ), porosity (Φ) and water absorption (WA)) of the created specimens were investigated. The obtained results, for all RPs, (especially those of 7.5% and 10%) exhibited an increase in the CS of the specimens by 15.4% and 7.8%, respectively, with the MoE decreased in both cases by 18.1% and 23.8%, respectively. The rest of the examined specimens' physical properties measured (ρ, Φ, and WA) indicated, also, greater strength but lower ductility than the reference (standard) specimen. Concluding, the use of recovered plastics from WEEE as recycled aggregates (RAs) in cement could potentially be proved a useful downcycling alternative for waste plastics.

Solvent versus thermal treatment for glass recovery from end of life photovoltaic panels: Environmental and economic assessment

End of life photovoltaic panels of different technologies (poly crystalline Si, amorphous Si, and CdTe) were treated mechanically in pilot scale by single shaft shredder minimizing the production of fine fractions below 0.4 mm (<18% weight). Grounded material was sieved giving: an intermediate fraction (0.4-1 mm) of directly recoverable glass (18% weight); a coarse fraction (which should be further treated for encapsulant removal), and fine fractions of low-value glass (18%), which can be treated by leaching for the removal of metal impurities. Encapsulant removal from coarse fraction was successfully performed by solvent treatment using cyclohexane at 50 °C for 1 h giving high-grade glass (52% weight), which can be reused for panel production. Experimental results of solvent treatment were compared with those from thermal treatment by economic analysis and Life Cycle Assessment, denoting in both cases the advantages of solvent treatment in recovering high-value glass.

Simultaneous Recovery of Display Panel Waste Glass and Wastewater Boron by Chemical Oxo-precipitation with Fluidized-Bed Heterogeneous Crystallization

Silica-based carrier is a promising material for recovery of metal and nonmetal contaminants in chemical oxo-precipitation-fluidized bed crystallization (COP-FBC) system. Boron species are an essential element for plant growth and can cause health concerns in human beings at high concentrations in water environments. The composition of thin-film transistor liquid crystal display (TFT-LCD) contains a wide variety of metal oxides and can be tailored as promising functional mesoporous carriers for boron crystallization recovery in the presence of barium ions and hydrogen peroxide. In this study, waste-derived mesoporous aluminosilicate (MAS) nanomaterial in the presence of barium ions and hydrogen peroxide was used as a carrier for sustainable recovery of crystallized boron, a priority wastewaters pollutant. The MAS shows the hierarchically homogeneous distribution of nanostructured aluminosilicate particles with an average size of 12.8 ± 3.6 nm on the surface after the activation with Na₂CO₃ at 1000 °C. Moreover, the negatively charged surface and the mesoporous structure of MAS enhance the adsorption of Ba²⁺ onto MAS, and the Langmuir adsorption capacity of 105 mg/g is achieved, which is conducive to the enhancement of the recovery of boron species. Moreover, the recovery efficiency and crystallization ratio of boron by MAS can be up to 84.5 and 93.4%, respectively. The cross-sectional scanning electron microscopy images and the high-temperature X-ray diffraction results confirm the boron recovery mechanism that the negatively charged functional group as well as the mesoporosity of MAS triggers the rapid formation of needle-shaped precipitates of barium peroxoborate, and then converted to barium borate after calcination at 1050 °C. Results obtained in this study clearly demonstrate the possibility of fabricating environmentally benign mesoporous aluminosilicate adsorbents from TFT-LCD waste to sustainably recover and crystallize boron species from water and wastewater in COP-FBC.

End-of-Life Liquid Crystal Display Recovery: Toward a Zero-Waste Approach

End-of-life liquid crystal displays (LCD) represent a possible source of secondary raw materials, mainly glass and an optoelectronic film composed of indium (90%) and tin (10%) oxides. A strong interest for indium, classified as critical raw material, pushed research towards the development of high-efficiency recycling processes. Nevertheless, a deepened study of the technological innovation highlighted that only a small number of treatments included use of whole waste. Furthermore, these processes often need high temperatures, long times, and raw materials that have a significant environmental impact. In this context, this article shows an approach developed in accordance with the “zero waste” principles for whole, end-of-life LCD panel recycling. This process includes preliminary grinding, followed by cross-current acid leaching and indium recovery by zinc cementation, with efficiencies greater than 90%. A recirculation system further increases sustainability of the process. To enhance all waste fractions, glass cullets from leaching are used for concrete production, avoiding their disposal in landfill sites. Considering the achieved efficiencies, combined the simple design suitable for real-scale application (as confirmed by the related patent pending), this process represents an excellent example of implementing circular economy pillars.

Sustainable valorization of mesoporous aluminosilicate composite from display panel glasses waste for adsorption of heavy metal ions

The recycling of the huge amount of thin film transistor liquid crystal display (TFT-LCD) glass wastes has become one of the worldwide environmental issues. Herein, a novel and cost-effective synthesis method for the fabrication of mesoporous aluminosilicate composite (M-ANC) from the TFT-LCD waste has been developed to serve as the environmentally benign adsorbent for the removal of metal ions including Cu²⁺, Zn²⁺ and Ni²⁺. After melting at 1000 °C in the presence of Na₂CO₃ for phase separation, nanoparticles with average particle size of 12 nm appear on the surface of M-ANC, and subsequently results in the production of mesoporous structure with a surface area of 175 m² g^-1. The tailored M-ANC shows negatively charged and functional groups, which exhibits an excellent adsorption capacity toward metal ion removal in the pH range of 1.5-7.0. The maximum Langmuir adsorption capacity of Cu²⁺, Zn²⁺ and Ni²⁺ are determined to be 64.5, 34.0 and 23.1 mg g^-1, respectively, at pH 3.5. Moreover, the environmental applicability of M-ANC is evaluated by column experiment in the presence of real electroplating wastewater. M-ANC can effectively remove Ni²⁺ in the electroplating wastewater with the adsorption capacity of 18.7 mg g^-1. Results obtained in this study clearly indicate that M-ANC recycled from TFT-LCD is a novel environmentally friendly adsorbent toward metal ion removal, which can open a gateway to fabricate mesoporous aluminosilicate materials through the recycling of other electronic wastes for real environmental application to remove metal ions and other emerging pollutants in the contaminated water and wastewater.

Thermal treatment of liquid crystal display panel scraps: The metals migration and potential environmental risk in solid residue

Thermal treatment has been proved to be an efficient and promising method for organics removal from LCD panels and for resource recycling. Considering with the toxic metals contained in LCD panels and their potential risk, it is necessary to study and evaluate the metals behavior and potential risk associated with the thermal treatment of LCD panels. In this study, the migration and transformation behavior of ten metals (Cr, As, Al, In, Ni, Cu, Zn, Cd, Fe, Sn) in LCD panels were investigated during thermal treatment, as well as their potential environmental risk and leaching toxicity in solid residue were evaluated. Results showed that Cr, Ni, In, Cu and Fe exhibit obvious migration behavior from solid into gas phase/fly ash during thermal treatment, with the maximum migration rate of 52.8%, 54.7%, 37.7%, 30.8%, and 34.9% respectively under the experimental condition. Speciation transformation for the metals of Cr, Ni, In, Cu, Fe and Zn was also observed in solid residue after thermal treatment, which leads to the ecological risk increase of Cu, In and contamination risk increase of Fe. Meanwhile, the leachable concentration and leaching toxicity of Cu and Ni in solid residue showed increasing trend after thermal treatment. The results indicate that attentions should be paid on the emission control of Cr, Ni, In, Cu, Fe during thermal treatment of LCD panel scraps. Environmental risk of Cu, In, Fe and the leaching toxicity of Ni in solid residue after thermal treatment should also be concerned.

Improving waste electric and electronic equipment management at full-scale by using material flow analysis and life cycle assessment

This work has as main objective the analysis of waste from electric and electronic equipment (WEEE or e-waste) management through material flow analysis and life cycle assessment of a full-scale Italian facility that is significant about the e-waste flows treated (9900 t/y) and representative of a developed EU country about the industrial process outline, based on manual dismantling phases and physic-mechanical automatic processes. Three WEEE categories (i.e. R1-Cooling equipment, R2-Large household appliances and R3- TVs and screens) have been chosen with the reason that they are the most abundant in EU. The methodology was based on two end-of-life scenarios: S₀-partial recycling of valuable fractions and landfilling of the rest, which is conventional e-waste processing in Italian facilities; S₁-complete recycling of valuable fractions, limited incineration and landfilling of the rest, which describes what happens in the considered case study. Mass balance of the three treatment lines showed recycling rate (RR) values equal to: for R1 40% for S₀ and 80% for S₁; for R2 65% for S₀ and 99% for S₁; for R3 86% for S₀ and 91% for S₁, with significant fractions incinerated or landfilled only for R1 treatment line. Life cycle assessment considered transport (post-consumer collection), treatment, recycling, incineration and disposal. As main results, eco-toxicity aquatic potentials referring to marine and fresh water were the most relevant impact categories. In conclusion, recycling (mostly of metals) played a crucial role for environmental benefits, and transport and polyurethane plus rubber incineration for the environmental impacts.

Commercial indium recovery processes development from various e-(industry) waste through the insightful integration of valorization processes: A perspective

Recycling of the waste LCD and recovery of indium which is an important classified critical raw material rarely have been industrially valorized for the circular economy due to lack of technology. Waste specific technology development is a cost-intensive and time-consuming process for the recycling industry. Hence, integrating existing technology for the purpose can address the e-waste issue in general and waste LCD in particular. Waste LCD and LCD industry itching wastewater are two important challenges can be addressed through an insightful combination of two. Hence, here possible integration of waste LCD leaching process with ITO wastewater treatment has been focused on indium recovery purpose. From our perspective process integration can be managed in two different ways, i.e., waste-to-waste mix stream process and integration of two different valorization processes for complete recovery of indium. With reference to indium recovery and context of e-waste recovery the process integration can be managed in two different ways, i.e., (i) waste LCD leaching with ITO etching industry wastewater then valorized (Waste-to-waste mix stream), (ii) Integration of waste LCD leaching process with ITO wastewater treatment process (integration of two valorization processes).Through proposed process semiconductor manufacturing industry and ITO recycling industry can address various issues like; (i) waste disposal, as well as indium recovery, (ii) brings back the material to production stream and address the circular economy, (ii) can be closed-loop process with industry and (iii) can be part of cradle-to-cradle technology management and lower the futuristic carbon economy, simultaneously.

Evaluation and comparison of pre-treatment techniques for recovering indium from discarded liquid crystal displays

Over the last years, emerging incentives for secondary production of high tech-metals, found in e-waste, are created because of their increasing demand and economic issues associated with their primary production. Due to the very low share of these metals in e-waste, pre-treatment methods can result in an output fraction rich in the metals of interest and may, therefore, be essential. To this scope, the present article evaluates and compares the efficiency of four different pre-treatment approaches containing various steps for recovering indium (In) from liquid crystal displays (LCDs) in laptop computers. The pre-treatment steps, used in various combinations, are (a) dry mechanical crushing and sieving, (b) pyrolysis, (c) thermal shock and (d) gravimetric process. Also, in all approaches, liquid crystals were removed from the samples, before applying the mechanical crushing step, as these are toxic and potentially harmful to human health and the environment. The removal was achieved by ultrasonic irradiation or mild agitation and optimized in terms of time, temperature and solvent type and concentration. Then, the feasibility of each pre-treatment approach was evaluated based on two parameters: (a) the content of In in the resulting sample after pre-treatment and (b) the separated mass share (%) with larger indium content as compared to the original LCD panel. The results showed that In is highly liberated in the fractions consisting of finest particles (<25 μm and <53 μm) after dry mechanical crushing and sieving with a maximum content of 234 mg/kg, which is twice as much as in the raw material. However, these particles represented only about 14 wt% of the original LCD panel mass. On the contrary, thermal shock results indicated that this was the most efficient pre-treatment approach, as both the content of In and the separated LCD mass (%) remained in high levels. Finally, some economic aspects associated with the processes are presented.

Leaching of indium from end-of-life LCD panels via catalysis by synergistic microbial communities

Currently, a large amount of discarded liquid crystal displays (LCDs) are being produced, and the improper treatment of discarded LCDs causes serious environmental pollution problems. Indium is the most valuable metal in LCDs and is present in such devices at a concentration of over 0.025%. In this study, the bioleaching of indium from end-of-life LCD panels was comprehensively investigated through three methods: S-mediated pathway, Fe-mediated pathway and Mixed pathway of S- and Fe-mediated, which yielded maximum bioleaching efficiencies of approximately 100%, 0% and 78%, respectively. Microbial community analysis showed that the dominant functional bacteria under the S-mediated pathway were Acidithiobacillus. The Acidithiobacillus genus catalysed the leaching of indium, which was mainly achieved by indirect bioleaching. In addition, the microorganisms can secrete enzymes and extracellular polymeric substances, which also contributed to the leaching of indium. Therefore, this work provides an economical and efficient biological method for future research and practical applications in indium recovery from solid waste.

End of life liquid crystal displays recycling: A patent review

A huge quantity of end-of-life liquid crystal displays (LCD) is collected, every year, around the world. Nowadays, this equipment is disassembled, for the removal of hazardous components (e.g. the backlight fluorescent lamps), and the resulting panel is stored. The reason is the significant content of valuable fractions (e.g. glass, metals and liquid crystals) and the lack of a recycling process, sustainable from an economic and an environmental point of view. Considering the relevance of this critical issue, the scientific community focused on the development of different recovery strategies, summarized in several available reviews. Nevertheless, the literature has not yet dealt with the technological innovation aspect. With the aim of filling this gap, the present review presents the international patents about LCD recycling, from 1999 to 2017, using the Espacenet platform, that has access to all the most relevant patent databases worldwide. The inventions include a first waste disassembling, followed by the classification of the target fractions and the recovery of metal (e.g. indium, indium tin oxide) and non-metal (e.g. glass, polarizing film, liquid crystal) components.

A review on management of spent lithium ion batteries and strategy for resource recycling of all components from them

The wide use of lithium ion batteries (LIBs) has brought great numbers of discarded LIBs, which has become a common problem facing the world. In view of the deleterious effects of spent LIBs on the environment and the contained valuable materials that can be reused, much effort in many countries has been made to manage waste LIBs, and many technologies have been developed to recycle waste LIBs and eliminate environmental risks. As a review article, this paper introduces the situation of waste LIB management in some developed countries and in China, and reviews separation technologies of electrode components and refining technologies of LiCoO₂ and graphite. Based on the analysis of these recycling technologies and the structure and components characteristics of the whole LIB, this paper presents a recycling strategy for all components from obsolete LIBs, including discharge, dismantling, and classification, separation of electrode components and refining of LiCoO₂/graphite. This paper is intended to provide a valuable reference for the management, scientific research, and industrial implementation on spent LIBs recycling, to recycle all valuable components and reduce the environmental pollution, so as to realize the win-win situation of economic and environmental benefits.

Sequential determination of gallium, indium, and thallium in environmental samples after preconcentration on halloysite nanotubes using ultrasound-assisted dispersive micro solid-phase extraction

A preconcentration procedure for gallium, indium, and thallium using HNTs was developed prior to their sequential determination by HR-CS GFAAS.