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In this study, a novel mesoporous CdS/TiO 2 /SBA-15@carbon paper composite membrane was developed to enhance the visible-light responsive CO 2 photoreduction in an optofluidic membrane microreactor. The microscopic morphological and pore volume characterizations indicated that the incorporation of the mesoporous SBA-15 into the membrane development could greatly improve the specific surface area and pore volume. The optofluidic membrane microreactor with the newly-developed composite membrane was evaluated in terms of the methanol concentration and yield. Experimental results showed that the optofluidic membrane microreactor with mesoporous CdS/TiO 2 /SBA-15@carbon paper composite membrane yielded much better performance than did the one without the mesoporous SBA-15. For a given total amount of TiO 2 /SBA-15 in the composite membrane, too high dosage of TiO 2 in the composite membrane caused the reduction in the specific surface area and pore volume, thereby lowering the photocatalytic performance. In addition, it was found that the methanol concentration and yield firstly increased and then decreased with increasing the liquid flow rate. The increase of both the light intensity and NaOH concentration was able to enhance the methanol generation. The obtained results fully demonstrate the superiority of the newly-developed CdS/TiO 2 /SBA-15@carbon paper composite membrane for the CO 2 photoreduction. [ABSTRACT FROM AUTHOR]

Conventional gas–liquid–solid reactors usually face the gaseous reactant transport issues in association with the interface and liquid phase to immobilized solid catalysts. To resolve this problem, a catalytic membrane microreactor (CMMR) with the catalytic membrane formed by coating the catalysts on a thin PDMS film modified by dopamine was developed in this study, which not only eliminated the issues in the conventional gas–liquid–solid reactors but also provided a large surface-area-to-volume ratio to enhance the mass transport. The performance of the developed CMMR was evaluated by hydrogenation of nitrobenzene. It was found that the nitrobenzene conversion and operation stability was greatly improved by the CMMR as a result of enhanced mass transport of hydrogen. Parametric study was also performed in this work to explore how the operation conditions and reactor design affected the performance. It was shown that low liquid flow rate and high gas flow rate benefited for the improvement in the nitrobenzene conversion due to the increased residence time and hydrogen permeation rate through the membrane. The results on the effect of the inlet nitrobenzene concentration showed that an increase in the inlet nitrobenzene concentration increased the aniline concentration because of enhanced catalytic reaction rate but lowered the nitrobenzene conversion because of the overloaded liquid reactant. Besides, it was also shown that thinner membrane could enhance the hydrogen permeation through the membrane, thereby yielding higher nitrobenzene conversion. This study fully demonstrates the feasibility and superiority of the developed CMMR for the gas–liquid–solid reaction system. [ABSTRACT FROM AUTHOR]

A general ionic-assisted microwave-ultrasonic combined synthetic strategy was developed to fabricate Bi 2 E 3 (E = S, Se, and Te) hierarchitectures. To understand the crystal phase transformation and morphological evolution of Bi 2 S 3 hierarchical nanostructures, the fabrication of Bi 2 S 3 hierarchitectures was investigated by varying sulfidation time and chlorination time. A topotactic transformation from BiOCl microsphere to Bi 2 S 3 hierarchitectures was proposed. It was found that the structure, size, and morphology of Bi 2 S 3 hierarchitectures could be delicately engineered by varying chlorination time, alkyl chain length, and concentration of ionic liquid. Moreover, the as-prepared Bi 2 S 3 hierarchitectures displayed superior capacity of Cr(VI) photoreduction to P25 and irregular Bi 2 S 3 nanostructures under visible light irradiation. Effects of morphology, pH value of reaction system, Cr(VI) concentration, and catalyst dosage on the Cr(VI) photoreduction capacity of Bi 2 S 3 hierarchitectures were also discussed. The enhancement of photoreduction capacity is not only attributed to the intrinsic good electron transfer ability of Bi 2 S 3 , but also to synergetic effects of special architectures, wide photoresponse range, high light photoadsorption, high BET surface area and good electron-hole separation performance. The systematic condition experiments and Cr(VI) photoreduction in electroplating and tannery wastewater experiments further demonstrated that the hierarchical Bi 2 S 3 nanospheres can be used in the actual Cr(VI)-containing wastewater treatment. [ABSTRACT FROM AUTHOR]