Preferential association of PBDEs and PAHs with mineral particles vs. dissolved organic carbon: Implications for groundwater contamination at e-waste sites.

Polybrominated biphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) are commonly detected contaminants at e-waste recycling sites. Against the conventional wisdom that PBDEs and PAHs are highly immobile and persist primarily in shallow surface soils, increasing evidence shows that these compounds can leach into the groundwater. Herein, we compare the leachabilities of PBDEs vs. PAHs from contaminated soils collected at an e-waste recycling site in Tianjin, China. Considerable amounts of BDE-209 (0.3-2 ng/L) and phenanthrene (42-106 ng/L), the most abundant PBDE and PAH at the site, are detected in the effluents of columns packed with contaminated soils, with the specific concentrations varying with hydrodynamic and solution chemistry conditions. Interestingly, the leaching potential of BDE-209 appears to be closely related to the release of colloidal mineral particles, whereas the leachability of phenanthrene correlates well with the concentration of dissolved organic carbon in the effluent, but showing essentially no correlation with the concentration of mineral particles. The surprisingly different trends of the leachability observed between BDE-209 and phenanthrene is counterintuitive, as PBDEs and PAHs often co-exist at e-waste recycling sites (particularly at the sites wherein incineration is being practiced) and share many similarities in terms of physicochemical properties. One possible explanation is that due to its extremely low solubility, BDE-209 predominantly exists in free-phase (i.e., as solid (nano)particles), whereas the more soluble phenanthrene is mainly sorbed to soil organic matter. Findings in this study underscore the need to better understand the mobility of highly hydrophobic organic contaminants at contaminated sites for improved risk management.

Ex-ante life cycle evaluation of spent lithium-ion battery recovery: Modeling of complex environmental and economic impacts.

The recycling of lithium-ion batteries (LIBs) is essential for promoting the closed-loop sustainable development of the LIB industry. However, progress in LIB recycling technologies is slow. There are significant gaps between academic research and industrial application, which hinder the industrialization of new technologies and the improvement of existing ones. Here we show a universal model for spent LIB-lithium recycling (SliRec) to evaluate the applicability and upgrading potential across various recycling technologies. Instead of modeling the entire recycling process, we focus on partial processes to enable a comparative analysis of environmental and economic impacts. We find a strong correlation between lithium concentration (LC) and the advancement of recycling technologies, where higher LC is associated with a reduced carbon footprint and increased economic benefits. The implementation of high-level recycling technology can result in an 85.91% reduction in carbon footprint and a 5.97-fold increase in economic returns. Additionally, we explore the effects of technological interventions through scenario analysis, demonstrating that while low-level recycling technology faces more substantial challenges in upgrading, it holds greater potential for reducing carbon emissions (-2.38 kg CO2-eq mol-1) and enhancing economic benefits (CNY 11.04 mol-1). Our findings emphasize the significance of process modeling in evaluating the quality of spent LIB recycling technologies, and can provide comparative information for the application of emerging technologies or the upgrade of existing ones.

Recycling Fe and improving organic pollutant removal via in situ forming magnetic core-shell Fe3O4@CaFe-LDH in Fe(II)-catalyzed oxidative wastewater treatment.

Due to its high efficiency, Fe(II)-based catalytic oxidation has been one of the most popular types of technology for treating growing organic pollutants. A lot of chemical Fe sludge along with various refractory pollutants was concomitantly produced, which may cause secondary environmental problems without proper disposal. We here innovatively proposed an effective method of achieving zero Fe sludge, reusing Fe resources (Fe recovery = 100%) and advancing organics removal (final TOC removal > 70%) simultaneously, based on the in situ formation of magnetic Ca-Fe layered double hydroxide (Fe3O4@CaFe-LDH) nano-material. Cations (Ca2+ and Fe3+) concentration (≥ 30 mmol/L) and their molar ratio (Ca:Fe ≥ 1.75) were crucial to the success of the method. Extrinsic nano Fe3O4 was designed to be involved in the Fe(II)-catalytic wastewater treatment process, and was modified by oxidation intermediates/products (especially those with COO- structure), which promoted the co-precipitation of Ca2+ (originated from Ca(OH)2 added after oxidation process) and by-produced Fe3+ cations on its surface to in situ generate core-shell Fe3O4@CaFe-LDH. The oxidation products were further removed during Fe3O4@CaFe-LDH material formation via intercalation and adsorption. This method was applicable to many kinds of organic wastewater, such as bisphenol A, methyl orange, humics, and biogas slurry. The prepared magnetic and hierarchical CaFe-LDH nanocomposite material showed comparable application performance to the recently reported CaFe-LDHs. This work provides a new strategy for efficiently enhancing the efficiency and economy of Fe(II)-catalyzed oxidative wastewater treatment by producing high value-added LDHs materials.

Soil colloids can significantly enhance spreading of polybromodiphenyl ethers in groundwater by serving as an effective carrier.

Polybromodiphenyl ethers (PBDEs), the widely used flame retardants, are common contaminants in surface soils at e-waste recycling sites. The association of PBDEs with soil colloids has been observed, indicating the potential risk to groundwater due to colloid-facilitated transport. However, the extent to which soil colloids may enhance the spreading of PBDEs in groundwater is largely unknown. Herein, we report the co-transport of decabromodiphenyl ester (BDE-209) and soil colloids in saturated porous media. The colloids released from a soil sample collected at an e-waste recycling site in Tianjin, China, contain high concentration of PBDEs, with BDE-209 being the most abundant conger (320 ± 30 mg/kg). The colloids exhibit relatively high mobility in saturated sand columns, under conditions commonly observed in groundwater environments. Notably, under all the tested conditions (i.e., varying flow velocity, pH, ionic species and ionic strength), the mass of eluted BDE-209 correlates linearly with that of eluted soil colloids, even though the mobility of the colloids varies markedly depending on the specific hydrodynamic and solution chemistry conditions involved. Additionally, the mass of BDE-209 retained in the columns also correlates strongly with the mass of retained colloids. Apparently, the PBDEs remain bound to soil colloids during transport in porous media. Findings in this study indicate that soil colloids may significantly promote the transport of PBDEs in groundwater by serving as an effective carrier. This might be the reason why the highly insoluble and adsorptive PBDEs are found in groundwater at some PBDE-contaminated sites.

Ce-doped TiO2 supported RuO2 as efficient catalysts for the oxidation of HCl to Cl2.

Reducing the cost of RuO2/TiO2 catalysts is still one of the urgent challenges in catalytic HCl oxidation. In the present work, a Ce-doped TiO2 supported RuO2 catalyst with a low Ru loading was developed, showing a high activity in the catalytic oxidation of HCl to Cl2. The results on some extensive characterizations of both Ce-doped TiO2 carriers and their supported RuO2 catalysts show that the doping of Ce into TiO2 can effectively change the lattice parameters of TiO2 to improve the dispersion of the active RuO2 species on the carrier, which facilitates the production of surface Ru species to expose more active sites for boosting the catalytic performance even under some harsh reaction conditions. This work provides some scientific basis and technical support for chlorine recycling.

Reversibly crosslinked polyurethane fibres from sugar-based 5-chloromethylfurfural: Synthesis, fibre-spinning and fibre-to-fibre recycling.

The development of recyclable crosslinked thermosetting fibres is a challenging research topic. In the present work, we have designed and synthesized polyurethane fibres from fructose-derived 5-chloromethylfurfural (CMF) and lignin-derived monomeric phenols. The greenhouse gas emissions associated with the production of CMF showed comparable results to that of 5-hydroxymethylfurfural (HMF), a high potential sugar-based platform molecule. The wet-spun biobased polyurethane fibres produced could be conveniently crosslinked using Diels-Alder chemistry to effectively enhance the glass transition temperature and mechanical properties. At a mildly elevated temperature (140 °C), the chemically crosslinked fibres could be effectively de-crosslinked, which enabled complete separation from a mixture with poly(ethylene terephthalate) (PET) and cotton fibres. These results outline a potential strategy to design and fabricate new biobased fibres with reversible crosslinking, which may enable fibre-to-fibre recycling.

Cell-wide arrangement of Golgi/RE units depends on the microtubule organization.

We have previously shown that Golgi stacks and recycling endosomes (REs) exist as Golgi/RE units in sea urchin embryos. In this study, we showed that Golgi/RE units were scattered throughout the cytoplasm at early developmental stages but gathered to form a "Golgi ring" surrounding the centric REs at the blastula stage. This change in the cell-wide arrangement of Golgi/RE units coincided with a dramatic change in microtubule organization from a randomly oriented cortical pattern to radial arrays under the apical plasma membrane. A single gigantic Golgi apparatus surrounding centric RE is clearly associated with the center of the radial microtubule arrays. Furthermore, we found that in some animal species belonging to different clades, Golgi stacks lack lateral connections but are likely centralized by microtubule motors. These results suggest that Golgi centralization depends on the organization of the microtubule array in addition to the lateral linking between Golgi stacks. Key words: Golgi stack, recycling endosome, Golgi-ribbon, microtubule, cilium, sea urchin, ascidian.

Closed-Loop Recycling of Wearable Electronic Textiles.

Wearable electronic textiles (e-textiles) are transforming personalized healthcare through innovative applications. However, integrating electronics into textiles for e-textile manufacturing exacerbates the rapidly growing issues of electronic waste (e-waste) and textile recycling due to the complicated recycling and disposal processes needed for mixed materials, including textile fibers, electronic materials, and components. Here, first closed-loop recycling for wearable e-textiles is reported by incorporating the thermal-pyrolysis of graphene-based e-textiles to convert them into graphene-like electrically conductive recycled powders. A scalable pad-dry coating technique is then used to reproduce graphene-based wearable e-textiles and demonstrate their potential healthcare applications as wearable electrodes for capturing electrocardiogram (ECG) signals and temperature sensors. Additionally, recycled graphene-based textile supercapacitor highlights their potential as sustainable energy storage devices, maintaining notable durability and retaining ≈94% capacitance after 1000 cycles with an areal capacitance of 4.92 mF cm⁻2. Such sustainable closed-loop recycling of e-textiles showcases the potential for their repurposing into multifunctional applications, promoting a circular approach that potentially prevents negative environmental impact and reduces landfill disposal.

Enhancement of liquid/gas production during co-pyrolysis of vacuum residue and plastics due to synergistic interactions.

Vacuum residue (VR) was copyrolysed with polyethylene (PE) or polystyrene (PS) in a batch reactor to investigate the corresponding synergistic pyrolytic interactions. The synergistic interactions between VR and plastic pyrolysates enhanced liquid and gas production while reducing coke formation, as compared with VR-only and plastic-only pyrolysis. The pyrolysis of 9:1 w/w VR: PE3M (PE with Mw = 3 MDa) and 9:1 w/w VR/PS350K (PS with Mw ≈ 350 kDa) mixtures produced oil in yields of 28.6 and 38.4 wt%, respectively, which exceeded those expected in the absence of synergistic interactions 1.12- and 1.29-fold, respectively. The corresponding coke yields were ~ 0.9 times lower than those expected in the absence of synergistic interactions. Moreover, copyrolysis synergistically increased the yields of oil-phase paraffins and olefins while decreasing that of aromatic compounds and was therefore concluded to enable effective VR utilisation and plastic recycling by enhancing liquid and gas production.

Recycling of Acrylonitrile Butadiene Styrene from Electronic Waste for the Production of Eco-Friendly Filaments for 3D Printing.

In this work, acrylonitrile butadiene styrene (ABS) copolymer from electronic waste (e-waste) was used to produce filaments for application in 3D printing. Recycled ABS (rABS) from e-waste was blended with virgin ABS (vABS) in different concentrations. By differential scanning calorimetry, it was observed that the values of the glass transition temperatures for vABS/rABS blends ranged between the values of vABS and rABS. Torque rheometry analysis showed that the processability of vABS was not compromised with the addition of rABS. Rheological measurements showed that the viscosity of vABS was higher than that of rABS at low frequencies and indicated that vABS and rABS are immiscible. Impact strength (IS) tests of the 3D printed samples showed an increase in the IS with an increase in the rABS content up to 50 wt%. Blending vABS with rABS from e-waste is promising and proved to be feasible, making it possible to recycle a considerable amount of plastics from e-waste and, thus, contributing to the preservation of the environment.

Synthesis of nanoporous carbon from Ulva lactuca activated by eggshell for CO2 capture: a novel approach to waste valorization.

Facing the daunting challenge of climate change, driven by escalating greenhouse gas concentrations, our research introduces an innovative solution for CO2 capture. We explore a novel nanoporous carbon derived from Ulva lactuca, activated with eggshell waste, spotlighting waste valorization in mitigating atmospheric CO2. Through a systematic methodology encompassing variable carbonization temperatures (700-900 °C) and nitrogen flow rates (2-4 ml/min), complemented by a suite of characterization techniques, we unveil the synthesis of this pioneering adsorbent. Our study not only presents a novel, sustainable pathway for CO2 capture but also demonstrates superior performance, particularly with the NC800-4 sample, achieving a CO2 capture capacity of 1.40 mmol/g at 30 °C, alongside demonstrating consistent adsorption efficiency over four successive adsorption/desorption cycles. This breakthrough underscores the potential of leveraging waste for environmental remediation, offering a dual solution to waste management and carbon capture, utilization, and storage (CCUS) applications.

Dataset on recovered waste post-earthquake 2016 in Manabi Province, Ecuador for recycling and reuse.

The earthquake in Ecuador on 16 April 2016 generated large volumes of debris and waste. This dataset contains data on recovered and reused disaster materials. Data were collected through a census survey of the scrap dealers of earthquake 2016 debris and waste (n = 62). This dataset was compiled to demonstrate how earthquake waste was generated during the 2016 earthquake and compare it with the pre-disaster period 2015 and the 2019 current when the data were collected. The recovered disaster materials include plastic, metal, cardboard, paper, glass, other recyclable materials, and reused materials. Likewise, the database allows us to observe the time response of medium- and small-sized scrap businesses as scrap dealers engage in the commercial transaction of disaster materials, and this dataset shows the process phases of recovering disaster waste. In addition, the dataset includes profit perceptions and factual earnings from scrap businesses after an earthquake. Considering the significant volume of waste and debris generated, this database can provide useful data for evaluating disaster waste management as an important task in post-disaster recovery.

Toward High-Energy-Density Aqueous Zinc-Iodine Batteries: Multielectron Pathways.

Aqueous zinc-iodine batteries (ZIBs) based on the reversible conversion between various iodine species have garnered global attention due to their advantages of fast redox kinetics, good reversibility, and multielectron conversion feasibility. Although significant progress has been achieved in ZIBs with the two-electron I-/I2 pathway (2eZIBs), their relatively low energy density has hindered practical application. Recently, ZIBs with four-electron I-/I2/I+ electrochemistry (4eZIBs) have shown a significant improvement in energy density. Nonetheless, the practical use of 4eZIBs is challenged by poor redox reversibility due to polyiodide shuttling during I-/I2 conversion and I+ hydrolysis during I2/I+ conversion. In this Review, we thoroughly summarize the fundamental understanding of two ZIBs, including reaction mechanisms, limitations, and improvement strategies. Importantly, we provide an intuitive evaluation on the energy density of ZIBs to assess their practical potential and highlight the critical impacts of the Zn utilization rate. Finally, we emphasize the cost issues associated with iodine electrodes and propose potential closed-loop recycling routes for sustainable energy storage with ZIBs. These findings aim to motivate the practical application of advanced ZIBs and promote sustainable global energy storage.

Prediction of metal recovery potential of end-of-life NEV batteries in China based on GRA-BiLSTM.

As Chinese new energy vehicle (NEV) sales continue to grow, end-of-life batteries have great potential for recycling in the future. In this study, a combined model based on Gray Relation Analysis and Bi-directional Long Short-Term Memory (GRA-BiLSTM) is proposed for predicting NEV sales, and the NEV battery life is modeled using the Weibull distribution. Then, the amount of end-of-life batteries, secondary utilization and metal recycling are calculated. The impact of end-of-life battery recycling on the supply and demand of key metals is studied. The results show that in 2040, the secondary utilization of end-of-life batteries in the Standard Growth Rate-Lithium Iron Phosphate Battery Dominated-High Secondary Utilization rate scenario (SGR-LFPH) is 391.76 GWh. The recycling volumes of lithium, nickel and cobalt are 45,900 tons, 92,900 tons and 22,100 tons, respectively. In the Standard Growth Rate-lithium nickel cobalt manganese oxide Battery Dominated-Low Secondary Utilization rate scenario (SGR-NCML), the recycling of lithium, nickel and cobalt is even greater, at 62,600 tons, 372,200 tons and 71,700 tons, respectively. End-of-life batteries recycling can reduce the demand for metals. However, as NEV sales continue to grow, the gap between metal supply and demand remains significant. The findings urge the Chinese government develop appropriate battery management strategies to increase the recycling rate of end-of-life batteries; and to encourage enterprises to research new types of batteries to resolve the conflict between supply and demand for metals.

Removal and recovery of phosphorus and fluorine in process water from water based direct physical lithium-ion battery recycling.

In the present work, the recovery of phosphorus and fluorine from process water generated in a water based direct physical recycling process of Li-ion batteries has been studied. The recycling process considered in this work produces significant amounts of process water, which is generated during the opening of the batteries by means of electro-hydraulic fragmentation and the subsequent sorting of the components in aqueous solution. This process produces between 21.6 L and 30.3 L of process water per kg of batteries with a total phosphorus and a total fluorine concentration of 60-85 mg/L and 120-470 mg/L, respectively. Currently, the process water has to be disposed of as hazardous waste. The goal is to discharge the wastewater into the sewer system. For this the total phosphorus and total fluorine concentration must be reduced. The process water is mainly contaminated by the released electrolyte consisting of organic carbonates and conducting salts. 31-P and 19-F NMR shows conclusively that no hydrolysis takes place in this process water. The phosphorus is present exclusively in the form of the complex anion PF6- and fluorine as F-, namely as FSI- from the conducting salt LiFSI and PF6- from the conducting salt LiPF6. In order to meet the regulatory requirements for discharge into the sewage system, 70.4% of the phosphorus and 89.3% of the fluorine must be removed. The conducting salts are hydrolyzed by adding acid and thereby phosphate and fluoride are precipitated. After critical and valuable materials are recovered the process water can be discharged into the sewer system.

Soft-Rigid Construction of Mechanically Robust, Thermally Stable, and Self-Healing Polyimine Networks with Strongly Recyclable Adhesion.

Reversible and recyclable thermosets have garnered increasing attention for their smart functionality and sustainability. However, they still face challenges in balancing comprehensive performance and dynamic features. Herein, silicon (Si)─oxygen (O) and imidazole units covalent bonds are coupled to generate a new class of bio-polyimines (Bio-Si-PABZs), to endow them with high performance and excellent reprocessing capability and acid-degradability. By tailoring the molar content of diamines, this Bio-Si-PABZs displayed both a markedly high glass transition temperature (162 °C) and a high char yield at 800 °C in an oxygen atmosphere (73.1%). These Bio-Si-PABZs with their favorable properties outperformed various previously reported polyimines and competed effectively with commercial fossil-based polycarbonate. Moreover, the scratch (≈10 µm) on the surface of samples can be self-healing within only 2 min, and an effective "Bird Nest"-to-"Torch" recycling can also be achieved through free amines solution. Most importantly, a bio-based siloxane adhesive derived from the intermediate Bio-Si-PABZ-1 by acidic degradation demonstrated broad and robust adhesion in various substrates, with values reaching up to ≈3.5 MPa. For the first time, this study lays the scientific groundwork for designing robust and recyclable polyimine thermosets with Si─O and imidazole units, as well as converting plastic wastes into thermal-reversibility and renewable adhesives.

Reusable Microfluidic Chambers for Single-Molecule Microscopy.

Maintaining a consistent environment in single-molecule microfluidic chambers containing surface-bound molecules requires laborious cleaning and surface passivation procedures. Despite such efforts, variations in nonspecific binding and background signals commonly occur across different chambers. Being able to reuse the chambers without degrading the surface promises significant practical and fundamental advantages; however, this necessitates removing the molecules attached to the surface, such as DNA, proteins, lipids, or nanoparticles. Biotin-streptavidin attachment is widely used for such attachments, as biotin can be readily incorporated into these molecules. In this study, we present single-molecule fluorescence experiments that demonstrate effective resetting and recycling of the chambers at least 10 times by using photocleavable biotin (PC-biotin) and UV-light exposure. This method differs from alternatives as it does not utilize any harsh chemical treatment of the surface. We show that all bound molecules (utilizing various PC-biotin attachment chemistries) can be removed from the surface by a 5 min UV exposure of a specific wavelength. Nonoptimal wavelengths and light sources showed varying degrees of effectiveness. Our approach does not result in any detectable degradation of surface quality as assessed by the nonspecific binding of fluorescently labeled DNA and protein samples and the recovery of the DNA secondary structure and protein activity. The speed and efficiency of the resetting process, the cost-effectiveness of the procedure, and the widespread use of biotin-streptavidin attachment make this approach adaptable for a wide range of single-molecule applications.

Stable isotopes analysis combined with X-ray absorption spectroscopy reveal the fate of organic waste-borne copper and zinc in amended soils.

Copper (Cu) and zinc (Zn), two potentially toxic trace elements, are commonly abundant in organic wastes (OWs) recycled in soils as fertilizer. Yet current knowledge on the long-term behavior and fate of Cu and Zn in soil following OW spreading is scant. We addressed this issue by studying the fate of OW-borne Cu and Zn in amended soils from four different long-term field experiments. By combining the stable isotope analysis and X-ray absorption spectroscopy, we identified changes in Cu and Zn concentrations, speciation and isotopic compositions in the amended soils only when OW had been applied at high rates over long periods. Under these conditions, we highlighted that: (i) all OW-derived Cu and Zn had accumulated in the topsoil layer regardless of the soil and OW type; (ii) the amended soil isotopic signatures were the result of the mixing of OW-borne and natural Cu and Zn; and (iii) Cu and Zn exhibited distinct speciation patterns in amended soils. Indeed, the unprecedented persistence of OW-borne crystallized Cu(I)-sulfide in the amended soils contrasted with the complete transformation of pig slurry-borne nanosized Zn-sulfide or household compost-derived amorphous Zn phosphate and Zn complexed by organic matter.

A comprehensive review on integrating sustainable practices and circular economy principles in concrete industry.

This comprehensive review explores the integration of circular economy principles into the concrete industry, emphasizing their role in enhancing sustainability and resource efficiency. It covers the fundamental concepts of circular economy and examines the application of Life Cycle Assessment (LCA) in evaluating the environmental impacts of concrete production. The review highlights innovative strategies for recycling, reuse, waste reduction, and resource optimisation, showcasing how these approaches can transform concrete production practices. It also addresses the policy considerations, economic implications, and societal impacts associated with adopting circular economy practices. Furthermore, the review investigates recent technological advancements in circular concrete production, including self-healing concrete and 3D printing. By summarizing these findings and offering practical recommendations, the review aims to support the industry in transitioning towards more sustainable practices. This detailed analysis provides valuable insights into the benefits and challenges of circular economy adoption, helping stakeholders make informed decisions for a greener concrete sector.

tsCRISPR based identification of Rab proteins required for the recycling of Drosophila TRPL ion channel.

In polarized cells, the precise regulation of protein transport to and from the plasma membrane is crucial to maintain cellular function. Dysregulation of intracellular protein transport in neurons can lead to neurodegenerative diseases such as Retinitis Pigmentosa, Alzheimer's and Parkinson's disease. Here we used the light-dependent transport of the TRPL (transient receptor potential-like) ion channel in Drosophila photoreceptor cells to study the role of Rab proteins in TRPL recycling. TRPL is located in the rhabdomeric membrane of dark-adapted flies, but it is transported out of the rhabdomere upon light exposure and localizes at the Endoplasmatic Reticulum within 12 h. Upon subsequent dark adaptation, TRPL is recycled back to the rhabdomeric membrane within 90 min. To screen for Rab proteins involved in TRPL recycling, we established a tissue specific (ts) CRISPR/Cas9-mediated knock-out of individual Rab genes in Drosophila photoreceptors and assessed TRPL localization using an eGFP tagged TRPL protein in the intact eyes of these mutants. We observed severe TRPL recycling defects in the knockouts of Rab3, Rab4, Rab7, Rab32, and RabX2. Using immunohistochemistry, we further showed that Rab3 and RabX2 each play a significant role in TRPL recycling and also influence TRPL transport. We localized Rab3 to the late endosome in Drosophila photoreceptors and observed disruption of TRPL transport to the ER in Rab3 knock-out mutants. TRPL transport from the ER to the rhabdomere ensues from the trans-Golgi where RabX2 is located. We observed accumulated TRPL at the trans-Golgi in RabX2 knock-out mutants. In summary, our study reveals the requirement of specific Rab proteins for different steps of TRPL transport in photoreceptor cells and provides evidence for a unique retrograde recycling pathway of TRPL from the ER via the trans-Golgi.