Renewable conversion of coal gangue to 13-X molecular sieve for Cd^(2+)-containing wastewater adsorption performance

Using coal gangue(CG)as raw material,a new type of all solid-waste-based 13-X molecular sieve material was controllably prepared by alkali fusion-hydrothermal method.The synthetic molecular sieve was used as a solid adsorbent to treat Cd^(2+)-containing wastewater,and its adsorption behavior on Cd^(2+)in aqueous solution was studied and analyzed.The microstructure and morphology of the molecular sieve were investigated by X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM)and specific surface area analyzer.The results show that the synthesized 13-X molecular sieve has higher Brunauer–Emmett–Teller(BET)specific surface area with higher crystallinity and higher adsorption capacity for the heavy metal Cd^(2+).The adsorption process of Cd^(2+)by molecular sieve conforms to the Langmuir isotherm adsorption equation and Lagergren pseudo-second-order rate equation.Combined with thermodynamic calculation,it can be concluded that the adsorption process is physically monolayer,spontaneous and exothermic.In this study,a low-cost and naturally available synthesis method of 13-X molecular sieve is reported.Combined with its adsorption mechanism for Cd^(2+),it provides a feasible and general method for removing heavy metal ions from coal gangue and also provides a new way for the utilization of coal gangue with high added value.

Robust and flexible 3D integrated FeNi@NHCFs air electrode for high-performance rechargeable zinc-air battery

Designing bifunctional oxygen reduction/evolution(ORR/OER)catalysts with high activity,robust stability and low cost is the key to accelerating the commercialization of rechargeable zinc-air battery(RZAB).Here,we propose a template-assisted electrospinning strategy to in situ fabricate 3D fibers consisting of FeNi nanoparticles embedded into N-doped hollow porous carbon nanospheres(FeNi@NHCFs)as the stable binder-free integrated air cathode in RZAB.3D interconnected conductive fiber networks provide fast electron transfer pathways and strengthen the mechanical flexibility.Meanwhile,N-doped hollow porous carbon nanospheres not only evenly confine FeNi nanoparticles to provide sufficient catalytic active sites,but also endow optimum mass transfer environment to reduce diffusion barrier.The RZABs assembled by FeNi@NHCFs as integrated air cathodes exhibit outstanding battery performance with high open-circuit voltage,large discharge specific capacity and power density,durable cyclic stability and great flexibility.Thus,this work brings a useful strategy to fabricate the integrated electrodes without using any polymeric binders for metal air batteries and other related fields.

Construction of novel TiO2/Bi4Ti3O(12)/MoS2 core/shell nanofibers for enhanced visible light photocatalysis

TiO2/Bi4 Ti3 O12 hybrids have been widely prepared as promising photocatalysts for decomposing organic contaminations.However,the insufficient visible light absorption and low charge separation efficiency lead to their poor photocatalytic activity.Herein,a robust methodology to construct novel TiO2/Bi4 Ti3 O12/MoS2 core/shell structures as visible light photocatalysts is presented.Homogeneous bismuth oxyiodide(BiOI) nanoplates were immobilized on electrospun TiO2 nanofiber surface by successive ionic layer adsorption and reaction(SILAR) method.TiO2/Bi4 Ti3 O12 core/shell nanofibers were conveniently prepared by partial conversion of TiO2 to high crystallized Bi4 Ti3 O12 shells through a solid-state reaction with BiOI nanoplates,which is accompanied with certain transition of TiO2 from anatase to rutile phase.Afterwards,MoS2 nanosheets with several layers thick were uniform decorated on the TiO2/Bi4 TiO3 O12 fiber surface resulting in TiO2/Bi4 Ti3 O12/MoS2 structures.Significant enhancement of visible light absorption and photo-generated charge separation of TiO2/Bi4 Ti3 O12 were achieved by introduction of MoS2.As a result,the optimized TiO2/Bi4 Ti3 O12/MoS2-2 presents 60% improvement for photodegrading RhB after 120 min irradiation under visible light and 3 times higher of apparent reaction rate constant in compared with the TiO2/Bi4 Ti3 O12.This synthetic method can also be used to establish other photocatalysts simply at low cost,therefore,is suitable for practical applications.