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Stainless steel wire mesh packing is widely used for experimental and industrial applications in rotating packed beds (RPBs) for gas−liquid contacting because it has a higher mass-transfer performance than other conventional packings. In this work, the gas−liquid effective interfacial area of a conventional RPB was studied with eight types of stainless steel wire mesh packings, consisting of four different stainless steel fibers. Gas−liquid chemisorption with CO 2 in NaOH solution was employed to measure the effective interfacial area for all types of packings with different rotational speeds and gas−liquid ratios. An empirical correlation that takes the effects of the fiber diameter and opening size of the wire mesh into consideration was proposed for the calculation of the gas−liquid effective interfacial area of stainless steel wire mesh packings in a conventional RPB.

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In this work, gas−liquid mass transfer characteristics, such as effective interfacial area (a e ) and liquid side mass transfer coefficient (k L ), were investigated in a rotating packed bed (RPB) contactor with 5 novel rotors equipped with blades in the packing section and 1 conventional rotor without blades and fully filled with the same packing. The chemisorption of CO 2 into a NaOH solution was used to evaluate a e and k L within each rotor of the RPB. The experimental results indicate that the rotors with blades can significantly intensify the mass transfer process at all rotational speeds, over a range of gas−liquid ratios. The mass transfer rate achieved within these novel rotors was between 8% and 68% higher in comparison with the conventional rotor. A model based on the Danckwerts surface renewal theory was developed to calculate the liquid side volumetric mass transfer coefficient (k L a e ) in the rotor. The experimentally obtained values of k L a e are in agreement with model predictions within ±15%.

Porous hollow silica nanoparticles (PHSNs) with a diameter of ca 100 nm and a pore size of ca 4.5 nm were synthesized via a sol-gel route using inorganic calcium carbonate nanoparticles as templates. The synthesized PHSNs were subsequently employed as pesticide carriers to study the controlled release behaviour of avermectin. The avermectin-loaded PHSN (Av-PHSN) samples were characterized by BET, thermogravimetric analysis and IR, showing that the amount of avermectin encapsulated in the PHSN carrier could reach 58.3% w/w by a simple immersion loading method, and that most of the adsorption of avermectin on the Av-PHSN carrier might be physical. Avermectin may be loaded on the external surface, the pore channels in the wall and the inner core of the PHSN carriers, thus leading to a multi-stage sustained-release pattern from the Av-PHSN samples. Increasing pH or temperature intensified the avermectin release.

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