Songwen Tan

Behaviour of fouling-related components in an enhanced membrane bioreactor using marine activated sludge.

This paper presents an experimental study on behaviour of fouling-related components during saline wastewater treatments in an enhanced mesoporous membrane bioreactor (MBR) system integrated with a biological contact oxidation reactor (BCOR). By monitoring the transmembrane pressure, the MBR system without BCOR assistance was observed to get membrane fouling easier during saline wastewater treatments. Typically, the concentration of total EPS gradually increased in the MBR system over the operation time, while no significant change in its concentration was observed in the BCOR-MBR system. The concentration of total SMP in the MBR system reached high levels earlier than the BCOR-MBR system, causing a significant membrane fouling. Besides, unlike a simple MBR system, the BCOR-MBR system produced more soluble microbial by-product-like components (simple) instead of fulvic acid-like or humic acid-like components (complex) during the saline wastewater treatments, resulting in higher resistance to a membrane fouling.

Effect of spray-drying temperature on the formation of flower-like lactose for griseofulvin loading

ABSTRACT The effect of spray‐drying temperature has been studied for the first time on the formation of flower‐like lactose for drug loading in this work. The synthesis of the flower‐like lactose involves two steps, namely spray drying and ethanol washing. Four inlet temperatures (140 °C, 150 °C, 160 °C and 200 °C) have been used in the spray‐drying step. The effect of the spray‐drying temperature was significant on the formation of flower‐like lactose, in terms of crystallinity, porosity and drug loading capacity. Higher inlet temperatures are more likely to produce lactose in the &bgr; form. The engineered flower‐like lactose is highly porous, with pores of 1.4, 3.4 and 29.3 nm (diameter). Compared with other inlet temperatures, the flower‐like lactose dried at 150 °C has the lowest degree of crystallinity, the largest pore surface area (38 ± 4 m2/g) and pore volume (0.65 ± 0.09 cm3/g), and the highest griseofulvin loading capacity (16.2 ± 0.3%, w/w). A griseofulvin dissolution test has suggested that the flower‐like lactose can be used as a drug carrier to enhance drug solubility. Graphical abstract Figure. No Caption available.

Role of templating agents in the spray drying and postcrystallization of lactose for the production of highly porous powders

ABSTRACT In this work, we report a method using templating techniques in spray drying to fabricate porous lactose with flower-like shapes. Three templating agents, including boric acid, citric acid, and ascorbic acid, have been used and compared for the production of flower-like lactose. The role of templating agents has been found to be significant in spray drying and postcrystallization of lactose. After spray drying, the boric acid (with a smaller size) is more likely to diffuse to the core of spray-dried particles than the other two templating acids. The morphology, pore structure, and crystallinity of the flower-like lactose have been found to be related to the use of different templating agents. The Brunauer–Emmet–Teller surface areas of the flower-like lactose are 29, 24, and 25 m2/g, respectively, for boric acid, citric acid, and ascorbic acid, as the templating agents. From the Barrett–Joyner–Halenda analysis, the citric acid-templated flower-like lactose has more large pores (radius > 61.8 Å), while the boric acid-templated lactose has more pores with a size of 28.2 Å (radius) and the ascorbic acid-templated lactose has more pores with a size of 15.2 Å (radius).