To separate small molecules/species, it’s crucial but still challenging to narrow the 2D-interspacing of graphene oxide (GO) membranes without damaging the membrane. Here the fast deposition of ultrathin, defect-free and robust GO layers is realized on porous stainless steel hollow fibers (PSSHFs) by a facile and practical electrophoresis deposition (ED) method. In this approach, oxygen-containing groups of GO are selectively reduced, leading to a controlled decrease of the 2D channels of stacked GO layers. The resultant ED-GO@PSSHF composite membranes featured a sharp cutoff between C2 (ethane and ethene) and C3 (propane and propene) hydrocarbons and exhibited nearly complete rejections for the smallest alcohol and ion in aqueous solutions. This demonstrates the versatility of GO based membranes for the precise separation of various types of mixtures. At the same time, a robust mechanical strength of the ED-GO@PSSHF membrane is also achieved due to the enhanced interaction at GO/support and GO/GO interfaces.

Microalgae are highly efficient cellular factories that capture CO2 and are also alternative feedstock for biofuel production. Carbohydrates, proteins, and lipids are major biochemical components in microalgae. Carbohydrates or starch in microalgae are possible substrates in yeast fermentation for biofuel production. The carbon partitioning in microalgae could be regulated through environmental stresses, such as high concentration of CO2, high light intensity, and nitrogen starvation conditions. It is essential to obtain carbohydrate-rich microalgae via an optimal bioprocess strategy. The carbohydrate accumulation in a CO2 tolerance strain, Chlorella sp. AE10, was investigated with a two-stage process. The CO2 concentration, light intensity, and initial nitrogen concentration were changed drastically in both stages. During the first stage, it was cultivated over 3 days under 1% CO2, a photon flux of 100 μmol m−2 s−1, and 1.5 g L−1 NaNO3. It was cultivated under 10% CO2, 1000 μmol m−2 s−1, and 0.375 g L−1 NaNO3 during the second stage. In addition, two operation modes were compared. At the beginning of the second stage of mode 2, cells were diluted to 0.1 g L−1 and there was no cell dilution in mode 1. The total carbohydrate productivity of mode 2 was increased about 42% compared with that of mode 1. The highest total carbohydrate content and the highest starch content of mode 2 were 77.6% (DW) and 60.3% (DW) at day 5, respectively. The starch productivity was 0.311 g L−1 day−1 and the total carbohydrate productivity was 0.421 g L−1 day−1 in 6 days. In this study, a novel two-stage process was proposed for improving carbohydrate and starch accumulation in Chlorella sp. AE10. Despite cell dilution at the beginning of the second stage, environmental stress conditions of high concentration of CO2, high light intensity, and limited nitrogen concentration at the second stage were critical for carbohydrate and starch accumulation. Although the cells were diluted, the growths were not inhibited and the carbohydrate productivity was improved. These results were helpful to establish an integrated approach from CO2 capture to biofuel production by microalgae.

The Cu/ZnO/Al ₂ O ₃ /Y ₂ O ₃ catalyst with Y ³⁺ : (Al ³⁺ + Y ³⁺ ) = 0.1 derived from hydrotalcite-like compounds exhibited the best catalytic performance with high stability.