Hybrid Surface Modification and Bulk Doping Enable Spent LiCoO2 Cathodes for High-Voltage Operation.

The emerging market demand for high-energy-density of energy storage devices is pushing the disposal of end-of-life LiCoO2 (LCO) to shift toward sustainable upgrading into structurally stable high-voltage cathode materials. Herein, an integrated bulk and surface commodification strategy is proposed to render spent LCO (S-LCO) to operate at high voltages, involving bulk Mn doping, near surface P gradient doping, and Li3PO4/CoP (LPO/CP) coating on the LCO surface to yield upcycled LCO (defined as MP-LCO@LPO/CP). Benefiting from hybrid surface coating with Li+-conductive Li3PO4 (LPO) and electron conductive CoP (CP) coupled with Mn and P co-doping, the optimized MP-LCO@LPO/CP cathode exhibits enhanced high-voltage performance, delivering an initial discharge capacity of 218.8 mAh g-1 at 0.2 C with excellent capacity retention of 80.9% (0.5 C) after 200 cycles at a cut-off voltage of 4.6 V, along with 96.3% of capacity retention over 100 cycles at 4.5 V. These findings may afford meaningful construction for the upcycling of commercial S-LCO into next-generation upmarket cathode materials through the elaborate surface and bulk modification design.

Simultaneous Separation and Recovery of Gold and Copper from Electronic Waste Enabled by an Asymmetric Electrochemical System.

Exploiting efficient strategies for the selective separation and extraction of valuable metals from e-waste is in urgent demand to offset the ever-increasing depletion of metal resources, satisfy the sustainable supply of metal resources, and reduce the environmental impact from toxic metals. Herein, an asymmetric electrochemical system, constructed by polyaniline (PANI) nanofibers grown on carbon cloth (CC) and CC as the respective counter and working electrodes, is presented for the simultaneous and selective extraction of gold and copper from e-waste leachate solution. Harnessing the established CC/PANI//CC system, CC/PANI as the anode electrode is capable of selectively and rapidly extracting gold with high efficiency, accompanied by excellent reusability. Meanwhile, cathodic CC electrode is found to achieve almost 100% recovery of copper at a voltage of -1.2 V. Furthermore, the feasibility of the proposed asymmetric electrochemical system is further exemplified in waste central processing unit (CPU) leaching solution, enabling to recover simultaneously gold and copper with high purity. This work will provide meaningful guidance for simultaneous separation and recovery of multiple valuable metals from real e-waste.

Hierarchical Porous Iron Metal-Organic Gel/Bacterial Cellulose Aerogel: Ultrafast, Scalable, Room-Temperature Aqueous Synthesis, and Efficient Arsenate Removal.

Rational design of advanced adsorbed materials with hierarchically porous architecture, high surface area, and macroscopic shapeability is of great significance for boosting their potential in practical applications. Herein, a monolithic iron metal-organic gel/bacterial cellulose (denoted as Fe-MOG/BC) composite has been successfully fabricated based on an ultrafast, scalable, aqueous-based synthetic strategy at room temperature. As expected, the resulting Fe-MOG/BC aerogel possesses a three-dimensional (3D) hierarchically porous microstructure and abundant active sites, being ultralight, water-fast, and mechanically robust. Benefiting from these unique structural characteristics, the resulting Fe-MOG/BC composite exhibits superb saturated sorption capacity (495 mg g-1) toward arsenate, outperforming other reported nanoadsorbents. Further, the Fe-MOG/BC aerogel enables efficient decontamination of 5 ppm of As(V) to below the permitted threshold in drinking water (10 ppb) within 30 min, accompanied by excellent selectivity and reusability. Significantly, as an efficient filter unit, the Fe-MOG/BC aerogel (0.1 g) can continuously treat 3900 mL wastewater (spiked with 1 ppm As(V)) to the safe level. Such an excellent As(V) decontamination capability of Fe-MOG/BC together with the ease, low cost, and scalable production prefigures its huge prospects for practical wastewater remediation.

A universal route to fabricate bacterial cellulose-based composite membranes for simultaneous removal of multiple pollutants.

A self-standing, robust bacterial cellulose (BC)-based multifunctional composite membrane embedded with desirable nano-adsorbents has been successfully fabricated via a facile versatile strategy. As expected, the developed BC-based composite membrane enables the simultaneous and efficient removal of multiple co-existing pollutants.

Hierarchically porous poly(amidoxime)/bacterial cellulose composite aerogel for highly efficient scavenging of heavy metals.

Developing cheap, green, efficient and renewable adsorbents to address the issue of heavy metal pollution is highly desired for satisfying the requirements of economy sustainability and water security. Herein, a composite aerogel composed of bacterial cellulose (BC) and poly(amidoxime) (PAO) has been fabricated via a facile and scalable self-assembly and in situ oximation transformation for heavy metals removal. Benefiting from the unique three-dimensional (3D) interconnected porous architecture and high density of amidoxime functional moieties, the developed PAO/BC composite aerogel is capable of efficiently sequestrating heavy metals with exceptional sorption capacities, e.g. 571.5 mg g-1 for Pb2+, 509.2 mg g-1 for Cu2+, 494 mg g-1 for Zn2+, 457.2 mg g-1 for Mn2+, and 382.3 mg g-1 for Cd2+, outperforming most reported nano-adsorbents. Meanwhile, the sorption equilibrium for the investigated five heavy metals is achieved within 25 min with high removal efficiencies. Significantly, the developed PAO/BC composite aerogels possess superior reusability performance. Furthermore, the PAO/BC aerogels-packed column can continuously and effectively treat the simulated wastewater with multiple heavy metals coexisting to below the threshold value in the drinking water recommended by World Health Organization (WHO), highlighting its feasibility in the complex environmental water.