Kok-Seng Lim

Versatile, High Quality and Scalable Continuous Flow Production of Metal-Organic Frameworks

Further deployment of Metal-Organic Frameworks in applied settings requires their ready preparation at scale. Expansion of typical batch processes can lead to unsuccessful or low quality synthesis for some systems. Here we report how continuous flow chemistry can be adapted as a versatile route to a range of MOFs, by emulating conditions of lab-scale batch synthesis. This delivers ready synthesis of three different MOFs, with surface areas that closely match theoretical maxima, with production rates of 60 g/h at extremely high space-time yields.

Scalability of Continuous Flow Production of Metal–Organic Frameworks

Achieving the large-scale production of metal-organic frameworks (MOFs) is crucial for their utilization in applied settings. For many MOFs, quality suffers from large-scale, batch reaction systems. We have developed continuous processes for their production which showed promise owing to their versatility and the high quality of the products. Here, we report the successful upscaling of this concept by more than two orders of magnitude to deliver unprecedented production rates and space-time-yields (STYs) while maintaining the product quality. Encouragingly, no change in the reaction parameters, obtained at small scale, was required. The production of aluminium fumarate was achieved at an STY of 97 159 kg m(-3)  day(-1) and a rate of 5.6 kg h(-1) .

Scalable simultaneous activation and separation of metal–organic frameworks

Despite the many promising applications of Metal–Organic Frameworks (MOFs) the key advances to boost production to industrial scale still remain elusive. Recently, it has been shown that continuous flow chemistry is capable of handling the production of a large variety of MOFs, while also being scalable. However commonly used laboratory methods for postproduction processing, i.e. separation and activation are ineffective and costly at scale. Here we present the use of megasonics, a novel and scalable methodology based on sonication with high frequency sound waves, which performs separation and activation simultaneously, yielding high surface areas that previously were only obtainable with laboratory-scale methods like solvent exchange, supercritrics and calcination.

Bubble Characteristics in a Developing Vertical Gas–Liquid Upflow Using a Conductivity Probe

Experiments were carried out in an 82.6-mm-dia column with a perforated distributor plate. Conductivity probes on the axis of the column were used to measure local bubble properties in the developing flow region for superficial air velocities from 0.0018 to 6.8 m/s and superficial water velocities from 0 to 0.4 m/s, corresponding to the discrete bubble, dispersed bubble, coalesced bubble, slug, churn, bridging, and annular flow regimes. Bubble frequency increased linearly with gas velocity in the discrete and dispersed bubble regimes. Bubble frequency also increased with gas velocity in the slug flow regime, but decreased in the churn and bridging regimes. Bubble chord length and its distribution were smaller and narrower in the dispersed than in the discrete bubble regime. Both the average and standard deviation of the bubble chord length increased with gas velocity in the discrete, dispersed, and churn flow regimes. The bubble travel length, defined as the product of local gas holdup and local bubble velocity divided by local bubble/void frequency, is used to correlate bubble characteristics and to characterize the flow regimes