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Mercury-dependent artisanal and small-scale gold mining (ASGM) is the largest source of mercury pollution on Earth. In this practice, elemental mercury is used to extract gold from ore as an amalgam. The amalgam is typically isolated by hand and then heated—often with a torch or over a stove—to distill the mercury and isolate the gold. Mercury release from tailings and vaporized mercury exceed 1000 tonnes each year from ASGM. The health effects on the miners are dire, with inhaled mercury leading to neurological damage and other health issues. The communities near these mines are also affected due to mercury contamination of water and soil and subsequent accumulation in food staples, such as fish—a major source of dietary protein in many ASGM regions. The risks to children are also substantial, with mercury emissions from ASGM resulting in both physical and mental disabilities and compromised development. Between 10 and 19 million people use mercury to mine for gold in more than 70 countries, making mercury pollution from ASGM a global issue. With the Minamata Convention on Mercury entering force this year, there is political motivation to help overcome the problem of mercury in ASGM. In this effort, chemists can play a central role. Here, the problem of mercury in ASGM is reviewed with a discussion on how the chemistry community can contribute solutions. Introducing portable and low-cost mercury sensors, inexpensive and scalable remediation technologies, novel methods to prevent mercury uptake in fish and food crops, and efficient and easy-to-use mercury-free mining techniques are all ways in which the chemistry community can help. To meet these challenges, it is critical that new technologies or techniques are low-cost and adaptable to the remote and under-resourced areas in which ASGM is most common. The problem of mercury pollution in ASGM is inherently a chemistry problem. We therefore encourage the chemistry community to consider and address this issue that affects the health of millions of people.

Mercury rising: The intentional use of mercury in artisanal and small-scale gold mining directly impacts the health of millions of people globally. Collaborative input from the chemistry community is required to help end this threat to the environmental and human well-being. The image was used with permission from Yayasan Tambuhak Sinta (YTS) and Pure Earth.

The direct conversion of waste cooking oil (WCO) into bio-jet fuel was investigated over a core-shell hierarchical USY@Al-SBA-15 zeolite-supported NiMo catalyst. The core-shell structure showed better acid and pore size distributions. The synergetic effect of the core-shell micropore and mesopore structure significantly contributed to enhancing the selectivity for the jet fuel (C_9–15 hydrocarbons) from 9.3 % over NiMo/USY up to 35.7 % over NiMo/USY@Al-SBA-15, with high isomerization (iso-/n-paraffins ratio = 2.7) and moderate aromatic fraction (18.7 %). The decarboxylation reaction was selectively enhanced. Optimal selectivity for jet fuel (39.7 %) was obtained at 380 °C and a high H₂/oil ratio would decrease the yield of jet fuel. This catalyst showed excellent stability for the hydroconversion of WCO to hydrocarbons.

A core-shell NiMo/USY@Al-SBA-15 catalyst with hierarchical pores was designed and synthesized for the conversion of waste cooking oil to jet fuel. The synergetic effect of the core-shell micropore/mesopore structure enhanced the selectivity for jet fuel and the stability of the catalyst. A high H₂/oil ratio was not favorable to improve the selectivity for C_9–15 hydrocarbons.

In article number 1705145, Sung Yeon Hwang, Dongyeop X. Oh, Jeyoung Park, and co-workers fabricate remarkably tough and room-temperature self-healable thermoplastic polyurethane elastomers. Hard segments with an asymmetric alicyclic structure provide the optimal metathesis efficiency for the embedded aromatic disulfide while preserving the remarkable mechanical properties. The toughness value of 26.9 MJ m⁻³ is twice the best value for a previously reported material.

We demonstrate an environmentally friendly one-step soap-free emulsion polymerization strategy to develop fluorescent carbazole-based copolymer monodisperse microspheres for highly sensitive and selective detection of Fe³⁺. The copolymer microspheres feature a stable spherical morphology with a narrow size distribution through regulating N-vinylcarbazole (NVCz) content (1.25–10.0 wt.%). Notably, the as-made microspheres exhibit a strong luminescence, tunable emission intensity and specific surface areas. Interestingly, the fluorescence of the copolymer microspheres can be selectively quenched by trace amounts of Fe³⁺ due to the oxidation of carbazole, and the quenching fluorescence can be facilely recovered by reduction with NaBH₄. Its excellent sensing performance is shown in terms of high sensitivity (low limit of detection, 1.3 μm), excellent selectivity, and rapid response rate, due to the porous nature of the copolymer microspheres. These results illustrate the copolymer microspheres obtained by simple preparative procedure without using expensive or toxic raw materials would serve as a high performance sensor for highly selective and recyclable detection of Fe³⁺ in aqueous medium.

Identifying iron: Novel fluorescent porous carbazole-containing copolymer monodisperse microspheres were prepared for highly selective and recyclable detection of Fe³⁺ in an aqueous medium.

The applications of three-dimensional superstructures that consist of metal–organic framework (MOF) crystals are promising, but limited by spatial control over the crystallization process. Here a hydrophobic hierarchical metal–organic framework (HZIF-8) containing unusual micro-, meso-, and macropores was designed and synthesized by a template strategy, in which the polystyrene (PS) not only acted as the template to construct the macropores, but also modified the hydrophilic crystal surface of ZIF-8. When used as adsorbent for liquid oil/water separation, HZIF-8 demonstrated significantly enhanced oil adsorption performance while maintaining very low water uptake.

Oil and water: A macroporous metal–organic framework (HZIF-8) with enhanced hydrophobicity was constructed via a rational and facile template route. HZIF-8 demonstrated significantly improved capacities for the adsorption of liquid oils while kept low water uptake.

Biomimetic functional surfaces are attracting increasing attention for various technological applications, especially the superhydrophobic surfaces inspired by plant leaves. However, the replication of the complex hierarchical microstructures is limited by the traditional fabrication techniques. In this paper, superhydrophobic micro-scale artificial hairs with eggbeater heads inspired by Salvinia molesta leaf was fabricated by the Immersed surface accumulation three dimensional (3D) printing process. Multi-walled carbon nanotubes were added to the photocurable resins to enhance the surface roughness and mechanical strength of the microstructures. The 3D printed eggbeater surface reveals interesting properties in terms of superhydrophobilicity and petal effect. The results show that a hydrophilic material can macroscopically behave as hydrophobic if a surface has proper microstructured features. The controllable adhesive force (from 23 μN to 55 μN) can be easily tuned with different number of eggbeater arms for potential applications such as micro hand for droplet manipulation. Furthermore, a new energy-efficient oil/water separation solution based on our biomimetic structures was demonstrated. The results show that the 3D-printed eggbeater structure could have numerous applications, including water droplet manipulation, 3D cell culture, micro reactor, oil spill clean-up, and oil/water separation.

A super-hydrophobic microsized eggbeater structure inspired by Salvinia molesta leaves is fabricated by an immersed surface accumulation 3D printing process. The 3D-printed eggbeater structure shows potential applications such as nonloss microdroplet manipulation and as 3D cell culture platform in biomedical engineering. Furthermore, it demonstrates a new energy-efficient solution for oil absorption and oil/water separation.

A cationic metal–organic framework (MOF), [Cu₂L(H₂O)₂]⋅(NO₃)₂⋅5.5 H₂O (1) has been successfully synthesized from a zwitterionic ligand 1,1′-bis(3,5-dicarboxyphenyl)-4,4′-bipyridinium chlorine ([H₄L]Cl₂). The framework of compound 1 contains classical {Cu₂(O₂C)₄} paddlewheels, and possesses typical nbo-type topology and two types of channels with sizes of 5.0 and 15.54 Å. Benefitting from the 3D cationic framework and high pore volume, compound 1 shows interesting selective adsorption ability for anionic dyes. Such material can be successfully employed in a chromatographic column to efficiently separate mixed dyes of Fluorescein Sodium and Methylene Blue. In addition, compound 1 exhibits excellent Cr₂O₇²⁻ removal capacity with maximum adsorption amount of 222.5 mg g⁻¹, which ranks among the higher Cr₂O₇²⁻ adsorption amounts of MOF materials ever reported, based on ion-exchange. The strategy to construct cationic MOFs based on zwitterionic ligands will promote the development of functional porous materials for the capture and removal of anionic pollutant species from contaminated liquid.

Capture the imagination: A new multifunctional cationic Cu-MOF based on zwitterionic ligand has been designed and synthesized. It exhibits selective dye capture and highly efficient Cr₂O₇²⁻ removal properties.