Potential Environmental and Human Health Impacts of Rechargeable Lithium Batteries in Electronic Waste

Rechargeable lithium-ion (Li-ion) and lithium-polymer (Li-poly) batteries have recently become dominant in consumer electronic products because of advantages associated with energy density and product longevity. However, the small size of these batteries, the high rate of disposal of consumer products in which they are used, and the lack of uniform regulatory policy on their disposal means that lithium batteries may contribute substantially to environmental pollution and adverse human health impacts due to potentially toxic materials. In this research, we used standardized leaching tests, life-cycle impact assessment (LCIA), and hazard assessment models to evaluate hazardous waste classification, resource depletion potential, and toxicity potentials of lithium batteries used in cellphones. Our results demonstrate that according to U.S. federal regulations, defunct Li-ion batteries are classified hazardous due to their lead (Pb) content (average 6.29 mg/L; σ = 11.1; limit 5). However, according to California regulations, all lithium batteries tested are classified hazardous due to excessive levels of cobalt (average 163 544 mg/kg; σ = 62 897; limit 8000), copper (average 98 694 mg/kg; σ = 28 734; limit 2500), and nickel (average 9525 mg/kg; σ = 11 438; limit 2000). In some of the Li-ion batteries, the leached concentrations of chromium, lead, and thallium exceeded the California regulation limits. The environmental impact associated with resource depletion and human toxicity is mainly associated with cobalt, copper, nickel, thallium, and silver, whereas the ecotoxicity potential is primarily associated with cobalt, copper, nickel, thallium, and silver. However, the relative contribution of aluminum and lithium to human toxicity and ecotoxicity could not be estimated due to insufficient toxicity data in the models. These findings support the need for stronger government policy at the local, national, and international levels to encourage recovery, recycling, and reuse of lithium battery materials

Leaching assessments of toxic metals in waste plasma display panel glass

<div><p>The plasma display panel (PDP) is rapidly becoming obsolete, contributing in large amounts to the electronic waste stream. In order to assess the potential for environmental pollution due to hazardous metals leached from PDP glass, standardized leaching procedures, chemical speciation assessments, and bioavailability tests were conducted. According to the Toxicity Characteristic Leaching Procedure (TCLP), arsenic in back glass was present at 4.46 ± 0.22 mg/L, close to its regulation limit of 5 mg/L. Zn is not available in the TCLP, but its TCLP leaching concentration in back glass is 102.96 ± 5.34 mg/L. This is because more than 90% of Zn is in the soluble and exchangeable and carbonate fraction. We did not detect significant levels of Ag, Ba, or Cu in the TCLP leachate, and the main fraction of Ag and Ba is residual, more than 95%, while the fraction distribution of Cu changes SEP by SEP. Ethylenediamine tetraacetic acid (EDTA)- and diethylenetriamine pentaacetic acid (DTPA)-extractable Ag, As, Ba, Cu, Zn, and Ni indicate a lower biohazards potential. These results show that, according to the EPA regulations, PDP glass may not be classified as hazardous waste because none of the metals exceeded their thresholds in PDP leachate. However, the concentrations of As and Zn should be lowered in the manufacturing process and finished product to avoid potential pollution problems.</p><p>Implications: <i>The plasma display panel is rapidly becoming obsolete because of the liquid crystal display. In this study, the leachability of heavy metals contained in the waste plasma display panel glass was first examined by standardized leaching tests, typical chemical speciation assessments, and bioavailability tests, providing fundamental data for waste PDP glass recovery, recycling, and reuse.</i></p></div

Metal-Organic Gels of Catechol-Based Ligands with Ni(II) Acetate for Dye Adsorption

Metal organic gels (MOGs) are a class of supramolecular complexes, which have attracted widespread interest because of the coupled advantages of inorganic and organic building blocks. A new compound terminated with catechol was synthesized. This new compound can be used to coordinate with Ni²⁺ to form MOGs. These MOGs show favorable viscoelasticity and wormhole-shaped porous structures, which were confirmed by transmission electron microscope and scanning electronic microscope images. Taking the benefits of porosity into account, the xerogel could serve as an adsorbent to adsorb dye molecules from the aqueous media. The experimental results indicate that xerogels possess good adsorption effect both on anionic and cationic dyes. Exhaustive research has been performed on the adsorption kinetics and isotherms, revealing that the adsorption process accords with the pseudo-second-order model and the Langmuir model

Self-Assembly and Rheological Properties of a Pseudogemini Surfactant Formed in a Salt-Free Catanionic Surfactant Mixture in Water

The surface and bulk properties of bola-type dicarboxylic acid (sebacic acid, SA) and zwitterionic surfactant tetradecyldimethylamine oxide (C₁₄DMAO) mixtures in aqueous solutions were studied. Surface tension measurements indicate a pronounced synergistic effect between SA and C₁₄DMAO. In bulk aqueous solutions, rich phase behavior was observed with a varied SA-to-C₁₄DMAO ratio (ρ) and a total surfactant concentration. Typically at ρ = 0.5, a novel pseudogemini surfactant (C₁₄-S-C₁₄) forms, driven by electrostatic interaction and hydrogen bonding. The C₁₄-S-C₁₄/H₂O system exhibits rich phase behavior induced by the transition of aggregates. With increasing concentration of C₁₄-S-C₁₄, one can observe a viscous L₁ phase, an L₁/L_α two-phase region where a birefringent L_α phase is on the top of an L₁ phase, a single L_α phase, and finally a mixture of an L_α phase and a precipitate. Microstructures formed in the L_α phases were determined by freeze–fracture transmission electron microscopy (FF-TEM) and cryogenic-transmission electron microscopy (cryo-TEM) observations. Polymorphic aggregation behavior was observed with the formation of a variety of bilayer structures including unilamellar vesicles, onions, and open and hyperbranched bilayers. Rheological measurements showed that the L_α phases are viscoelastic and sensitive to temperature where a quick loss of viscoelasticity was observed at elevated temperature

Self-Organization and Vesicle Formation of Amphiphilic Fulleromonodendrons Bearing Oligo(poly(ethylene oxide)) Chains

A new series of <i>N</i>-methylfulleropyrrolidines bearing oligo­(poly­(ethylene oxide))-appended Percec monodendrons (fulleromonodendrons, <b>4a</b>–<b>f</b>) have been synthesized. The substituted position of the oligo­(poly­(ethylene oxide)) chain(s) on the phenyl group of the Percec monodendron for <b>4a</b>–<b>f</b> was varied, which is at the 4-, 2,4-, 3,5-, 3,4,5-, 2,3,4- and 2,4,6- position, respectively. <b>4a</b>–<b>e</b> are obtained as solids at 25 °C and can self-organize into lamellar phases as revealed by X-ray diffraction (XRD) and small-angle X-ray scattering (SAXS) measurements, while <b>4f</b> appears as a viscous liquid. The substitution patterns of the oligo­(poly­(ethylene oxide)) chain(s) also significantly influence the solubility of <b>4a</b>–<b>f</b>, especially in ethanol and water. Formation of self-organized supramolecular structures of <b>4d</b> and <b>4e</b> in water as well as <b>4d</b> in ethanol is evidenced from UV–vis and dynamic light scattering (DLS) measurements. Further studies in water using various imaging techniques including transmission electron microscopy (TEM), freeze-fracture TEM (FF-TEM), cryo-TEM and atomic force microscopy (AFM) observations revealed the formation of well-defined vesicles for <b>4d</b> and plate-like aggregates for <b>4e</b>, indicating that the aggregation behavior of the fulleromonodendrons is highly dependent on their molecular structures. For <b>4d</b> in ethanol, only irregular aggregates were noticed, indicating the solvent also plays a role on regulating the aggregation behavior. After functionalization with the Percec monodendrons, <b>4a</b>–<b>f</b> can preserve the intriguing electrochemical properties of pristine C₆₀ as revealed by cyclic voltammetries. The thermotropic properties of <b>4a</b>–<b>f</b> have also been investigated. It was found that all of them show good thermal stability, but no mesophases were detected within the investigated temperature ranges