This work introduces a microfluidic method for the generation of monodispersed microdroplets by using temperature controlled bubble condensation processes. In this method, the dispersed phase is first vaporized in the feeding pipe and ruptured to monodispersed bubbles in a coflowing stream. These bubbles are then condensed in the downstream pipe, where monodispersed microdroplets are obtained. This method ensures the narrow distribution of droplet diameters and prepares microdroplets less than 200 μm in sub-millimeter fluidic devices.

A system for measuring the pressure drop of a fluid in a microchannel was developed in this study with measurements ranging from 0 to 7 kPa and an accuracy of 1 Pa for constant pressure drop. This system utilizes commercial pressure sensors, self-made amplifiers and a vibration insulation platform to insure accuracy and reproducibility of the results. Pressure calibrations can be conveniently computed using the manufacturers’ datasheet. This measuring system was firstly tested with the pressure drop measurement of single-phase flow in microchannels and the results showed good agreement with theoretical computations. Oscillating pressure drops in the generation of bubbles in T-junction microchannel were studied using the pressure measurement system and their amplitude relatively to the change of working systems is carefully discussed with the comparison of theoretical models from literatures.

This paper explores porous glass beads as a pollutant-free-prepared, low-cost, and recyclable adsorbent for desulfurization. Porous glass beads with a specific surface area, pore volume, and mean pore diameter of 162.6 m2 g−1, 0.26 cm3 g−1, and 6.34 nm, respectively, were obtained by subcritical water treatment. The effects of the surface chemistry of the adsorbent and the structure of the organosulfur molecules on adsorption capacity were studied; the software, Materials Studio, was used to calculate the interactions between the surface of the glass beads and the sulfur-containing compounds. Compared with these porous glass beads, two other kinds of porous glass beads modified by hexamethyldisilazane and hydrochloric acid, respectively, showed much lower adsorptive capacity for dibenzothiophene, indicating the metal ions contained in the glass played an important role during the adsorption; the capacities of the porous glass beads for benzothiophene, dibenzothiophene, and 4,6-dimethyldibenzothiophene were 6.47 ± 0.09, 8.58 ± 0.09, and 11.20 ± 0.08 mg(S) gadsorbent−1, respectively, corresponding to the simulation results. The adsorptive capacity for dibenzothiophene decreased with the increase of temperature but increased with the increase of initial concentration, the highest capacity of 10.29 ± 0.11 mg(S) gadsorbent−1 was obtained at 303 K with the initial concentration of 565 ppmw(S). Spent adsorbent can be regenerated by heating at high temperature, and the adsorptive capacity only decreased about 3.38% after five cycles. Experimental results and the computer simulations indicate that polar interactions between the surface and sulfur-containing compounds dominated the adsorption.

Caprolactam recovery from its dilute aqueous solution is a challenging task in industry. To save resources and protect environment, a caprolactam recovery technology based on extractant microcapsules as the separation material was introduced. In this new technology, polysulfone microcapsules containing 1-octanol were packed in a column. In the extraction process, recovery ratio of 0.99 was achieved within 0.6 bed volume. More than 10 theoretical plates per meter microcapsule column were realized. In the regeneration process, sulfuric acid aqueous solution was introduced as the stripping agent. Accordingly the new technology can be integrated with existing caprolactam production process because the eluent could be returned to NH3 causticization section. Caprolactam was successfully stripped and concentrated. Caprolactam concentration of 112 g/L in the eluent was obtained. New technology based on extractant microcapsules shows high efficiency in caprolactam recovery.