Here, we reported a strategy for channel methylation to construct a robust ultramicroporous metal–organic framework (MOF) Ni­(TMBDC)­(DABCO)0.5 through hydrothermal synthesis method and investigated its adsorption performance for recovering ethane (C2) and propane (C3) from natural gas. The as-synthesized Ni­(TMBDC)­(DABCO)0.5 featured ultramicroporosity with a uniform pore size of 0.5 nm. The resulting sample showed a strong adsorption interaction with C3H8 and C2H6, and its C3H8 adsorption capacity at a low pressure of 1 kPa was up to 2.80 mmol/g and its C2H6 adsorption capacity at a low pressure of 10 kPa reached as high as 2.93 mmol/g, exhibiting strong binding affinity for ethane and propane. The enhanced adsorption can be attributed to the presence of the dense and accessible methyl and methylene groups in the channels of the sample. Grand Canonical Monte Carlo (GCMC) simulations also confirmed that the methylene groups from the DABCO pillar and the methyl groups from the TMBDC ligand play an important role in enhancing the adsorption of ethane and propane. Its ideal adsorbed solution theory (IAST)-predicted selectivity of C2H6/CH4 reached unprecedentedly 29, much higher than most of the reported data for MOFs. The stability test confirmed that the crystal structure of Ni­(TMBDC)­(DABCO)0.5 still remained intact after it was exposed to moist air with a relative humidity of 100% for days. The breakthrough experiment demonstrated that the CH4/C2H6/C3H8 ternary mixture was completely separated using a fixed bed of Ni­(TMBDC)­(DABCO)0.5 at ambient temperature, showing a great potential for recovering the low content of ethane and propane from natural gas.

To develop dynamic ultra-deep catalytic adsorptive desulfurization (CADS) of real diesel using ultra-stable and lowcost silica gel-supported TiO 2 is the aim of the work. A two-stage dynamic breakthrough model was built to describe the CADS process, varied with H/R ratio and O/S ratio. The desulfurization capacity reached 1.3 mg-S/g-A at the breakthrough concentration of 5 ppm-S. Various types of silica gel were screened as the substrate for TiO 2 , and the textural/ acidic properties and CADS capacity were correlated in high relevancy. The effectiveness of diverse oxidants on CADS and the oxidation path were elucidated via combined experiment/simulation. Adsorption enthalpy derived from fitted isotherm data was calculated as 33.4 kJ/mol. The TiO 2 /silica gel-based sorbent demonstrated remarkable recyclability/ stability in 10 cycles. An effective and economic route to eliminate the trace amount of stubborn sulfur compounds in low-sulfur diesel is provided, which can be potentially implemented as the final polishing step for ultra-clean diesel production.

Hierarchical porous zeolitic imidazolate frameworks (ZIFs) have potential for adsorption, catalysis and chemical sensing applications. Ultrafast synthesis of ZIFs at room temperature and pressure is particularly desirable for large-scale industrial production. Here, we developed a green and versatile method using organic amines as supramolecular templates (organic amine-template) to rapidly synthesize hierarchical porous ZIFs (ZIF-8, ZIF-61 and ZIF-90) at room temperature and pressure. The synthesis time was reduced dramatically to within 1 min, and the resulting ZIFs had multimodal hierarchical porous structures with mesopores/ macropores interconnected with micropores. Notably, the space-time yield (STY) of hierarchical porous ZIF-8 was up to 1.29×10 4 kg m -3 d -1 , which is more than three times higher than that reported using other methods. Furthermore, the morphologies and porosities of the produced ZIFs could be readily tuned by controlling the synthesis time or type of organic amine. The organic amine played two roles in the synthesis: (1) a protonation agent to deprotonate organic ligands, facilitating the formation of ZIF crystals, and (2) an structure directing agent to direct mesopore/macropore formation. The resulting hierarchical porous ZIF-8 exhibited enhanced uptake capacities and diffusion rates for guest molecules relative to its microporous counterpart. This work provides a new direction for the green and efficient synthesis of various hierarchical porous ZIFs with high STYs for a wide range of applications.

Fabricating silver nanoparticles (AgNPs) based on renewable energy sources is wildly exploited because of the sustainable synthetic strategy and versatile applications of AgNPs. Alkali lignin (AL), as the byproduct from pulp mills, is a potential natural reducing agent. However, the synthetic methods of AL-based AgNPs (AL@Ag) still have drawbacks, such as unusual conditions and extra and high-cost purification processes. Here, a facile and efficient approach to synthesize and purify good-dispersing AL@Ag (17−27 nm) was presented, using Ag 2 O as the silver precursor and AL as both reducing agents and stabilizers in dimethyl sulfoxide (DMSO) solvent. The maximum reduction capacity of AL to Ag + was increased to 8 mM/g at room temperature because of the activation of both Ag 2 O and DMSO. Most conveniently, the product was effectively purified by easy centrifugation. The reducing mechanism and reaction behavior were also systematically studied. Meanwhile, AL@Ag maintained versatile applications of AgNPs and exhibited great potential as the colorimetric sensor and plasmonic resonance energy acceptor for Hg 2+ and rhodamine B, respectively. Our work displayed a general and efficient method to prepare AL@Ag, which might provide a realizable perspective to the high-value utilization of lignin.

Mechanochemical synthesis, driven the chemical transformation by mechanical force, has been a rapid and efficient strategy to prepare metal–organic frameworks (MOFs). In this work, a liquid-assisted mechanochemical method has been successfully applied to the synthesis of copper based MOF-505. The crystallinity and porosity of MOF-505 were investigated by adjusting the synthesis parameters, such as added solvent (type and amount) and grinding time. Results showed that the type and amount of added solvent were crucial parameters for the mechanochemical synthesis of MOF-505. Furthermore, the optimizations of MOF-505 synthesis were carried out: grinding Cu­(OAc)2·H2O and H4bptc as starting materials for 80 min with 0.4 mL of DMF assisted, giving MOF-505-K with Brunauer–Emmett–Teller (BET) surface area of 977 m2/g. Meanwhile, MOF-505-K had moderate CO2 adsorption capacity of 2.01 mmol/g at 298 K and 100 kPa. The adsorptive selectivity determined from ideal adsorbed solution theory (IAST) indicated that MOF-505-K had high CO2/N2 and CO2/CH4 selectivities (26.6 and 5.5) at 298 K. Highly efficient mechanochemical synthesis of MOF-505 provides the promise to facilitate the industrial application of CO2 capture.