Search

Converting poly(ethylene terephthalate) (PET) into metal–organic frameworks (MOFs) has emerged as a promising innovation for upcycling of waste plastics. However, previous solvothermal methods suffer from toxic solvent consumption, long reaction time, high pressure, and high temperature. Herein, a mechanochemical milling strategy was reported to transform waste PET into a series of MOFs with high yields. This strategy had the merits of solvent‐free conditions, ambient reaction temperature, short running time, and easy scale‐up for large‐scale production of MOFs. The as‐prepared MOFs exhibited definite crystal structure and porous morphology composed of agglomerated nanoparticles. It was proven that, under mechanochemical milling, PET was firstly decomposed into 1,4‐benzenedicarboxylate, which acted as linkers to coordinate with metal ions for forming fragments, followed by the gradual arrangement of fragments into MOFs. This work not only promotes high value‐added conversion of waste polyesters but also offers a new opportunity to produce MOFs in a green and scalable manner. [ABSTRACT FROM AUTHOR]

The controllable carbonization of waste plastics into functional carbon nanomaterials towards environmental remediation, energy conversion and storage has received widespread attention. However, there are few studies on the carbonization of poly(lactic acid) (PLA) into porous carbon. Herein, the controlled carbonization of PLA into crumped carbon nanosheet (CCN) is reported. Firstly, recycled PLA bags are converted into magnesium-based metal-organic framework (Mg-MOF) through the combined strategy of mechanochemical milling and solution mixing, and then Mg-MOF is transformed into CCN through the metal-organic framework (MOF)-assisted carbonization strategy. CCN exhibits merits of abundant nanopores and oxygen-containing groups. As a result, the CCN-derived evaporator holds good light absorptivity, low evaporation enthalpy, and good light-to-thermal conversion ability. Furthermore, the CCN-derived solar evaporator achieves a high evaporation rate (2.70 kg m−2 h−1) at 1 kW m−2 irradiation, along with good long-term stability, which surpasses many recent advanced solar evaporators. Noteworthy, when wastewater, lake water, seawater, tetracycline solution, and dye-polluted water are used, the CCN-based evaporator remains high performance in freshwater production. Importantly, an outdoor CCN-based device is constructed, which realizes the freshwater production of 6.3 kg m−2. The collected freshwater can cultivate well mung bean sprouts under natural condition. This work not only provides a new "turning-waste-into-treasure" method for the recycling of waste PLA, but also offers a novel strategy for the preparation of low-cost, functional carbon materials for diverse applications. [Display omitted] • Mg-MOF with daisy-like morphology is prepared from waste PLA bags in a green manner. • Carbon nanosheet with a thickness of 2.5 nm is obtained by carbonization of Mg-MOF. • The carbon nanosheet-based evaporator effectively realizes freshwater production. • Evaporator shows the evaporation rate of 2.71 kg m−2 h−1 with efficiency of 98.6%. • This work provides a new "turning-waste-into-treasure" strategy for PLA recycling. [ABSTRACT FROM AUTHOR]

Integrating interfacial solar steam generation with advanced oxidation process (AOP) is regarded as a promising strategy for addressing energy and environmental issues. However, developing dual-functional evaporators well-integrated with synergistic photothermal-AOP catalysis properties remains challenging. Herein, we synthesize cobalt-based metal-organic framework (Co-CAT) and prepare dual-functional Co-CAT evaporators. Co-CAT is endowed with "all-in-one" functions, i.e., high specific surface area, effective light absorption, and high catalytic activity. Co-CAT exhibits superior sunlight absorption and photo-to-thermal conversion property. The large specific surface area and abundant micropore of Co-CAT facilitate water permeation and evaporation enthalpy reduction. COMSOL Multiphysics and density functional theory calculation results prove that Co2+ sites in Co-CAT and heat localization promote peroxymonosulfate activation. Consequently, it not only exhibits a high-water evaporation rate of 2.2 kg m−2 h−1, outperforming the-state-of-art evaporators, but also presents the notable tetracycline degradation efficiency (91.1 %). This work proposes an ingenious way to deal with freshwater shortage and water pollution. [Display omitted] • Co-CAT with "all-in-one" functions is prepared by a facile hydrothermal method. • Co-CAT evaporator realizes wastewater purification and freshwater production. • Co-CAT owns good photothermal conversion ability and rises AOP catalysis efficiency. • Localized solar heat and rich open Co sites of Co-CAT promote the activation of PMS. • Evaporator shows an evaporation rate of 2.2 kg m−2 h−1 with TC removal of 91.1 %. [ABSTRACT FROM AUTHOR]

[Display omitted] • Semiconductive Co-MOF nanorod in large quantity is prepared from discarded PET. • Co-MOF/CNT evaporator realizes wastewater purification and freshwater production. • CNT owns good photothermal conversion ability and rises photocatalysis efficiency. • Localized solar heat and rich open Co site of Co-MOF promote the activation of PMS. • Evaporator shows an evaporation rate of 2.25 kg m−2h−1 with TC removal of 99.8 % Catalytic conversion of waste plastics into semiconductive metal–organic framework (MOF) kills two birds with one stone, since it not merely offers promising possibility to realize freshwater production and water decontamination through interfacial solar evaporation and photocatalysis, but also advances upcycling of waste plastics. Nevertheless, exploiting synergistic photothermal-photocatalysis materials from recycled plastics remains a challenge. Herein, we report a facile solvothermal method of waste poly(ethylene terephthalate) bottles for the massive production of Co-MOF nanorod and construct a dual-functional Co-MOF/carbon nanotube (CNT) solar evaporator integrated with advanced oxidation process for simultaneous wastewater purification and freshwater production. Firstly, we prove that the evaporator owns high sunlight absorption due to the presence of CNT, super-hydrophilicity, and low heat conductivity, which endow it with fine photothermal conversion capability and reduced vaporization enthalpy. Benefiting from the above advantages, Co-MOF/CNT evaporator displays a high evaporation rate of 2.25 kg m−2 h−1 under 1 kW m−2 illumination, when treating tetracycline (TC)-polluted water, along with good mechanical property, high flexibility, long-term stability, and high scalability. Secondly, based on the results of COMSOL and density functional theory calculation, the localized solar heat from CNT and rich open cobalt sites of Co-MOF nanorod are proved to play a synergistic effect in the activation of peroxymonosulfate to generate various oxidation reactive species. Thereby, the dual-functional evaporator achieves a superb TC degradation activity. Lastly, an outdoor device is designed for freshwater generation and catalytic decomposition of TC. The daily freshwater production amount is 4.5 kg m−2, and the TC degradation efficiency is 93.1%. This study not merely advances the upcycling waste plastics into useful products, but also offers a sustainable platform to wastewater purification via a waste-treating-waste strategy. [ABSTRACT FROM AUTHOR]