Comparison of slow sand filtration and microfiltration as pretreatments for inland desalination via reverse osmosis

A pilot study was conducted from October 2007 to November 2010 to establish the long-term feasibility of using reverse osmosis (RO) treatment to manage salt levels in Central Arizona Project water. Pretreatments consisting of microfiltration (MF) and slow sand filtration (SSF) were compared based on performance—turbidity removal, silt density index (SDI), volume treated between cleaning events and protection of downstream RO—during side-by-side operation over a yearlong period. SSF always produced feed water that was suitable for RO treatment (SDI < 5). However, MF consistently provided filtrate with SDI < 3, and long-term RO performance improved significantly with MF as pretreatment. Although the economic costs of MF and SSF pretreatments are similar; MF is preferred based on the quality of treated water and stability of downstream RO operation.     

Realizing the enhancement of interfacial interaction in semicrystalline polymer/filler composites via interfacial crystallization

Polymer/filler composites have been widely used in various areas. One of the keys to achieve the high performance of these composites is good interfacial interaction between polymer matrix and filler. As a relatively new approach, the possibility to enhance polymer/filler interfacial interaction via crystallization of polymer on the surface of fillers, i.e., interfacial crystallization, is summarized and discussed in this paper. Interfacial crystallization has attracted tremendous interest in the past several decades, and some unique hybrid crystalline structures have been observed, including hybrid shish-kebab and hybrid shish-calabash structures in which the filler served as the shish and crystalline polymer as the kebab/calabash. Thus, the manipulation of the interfacial crystallization architecture offers a potential highly effective route to achieve strong polymer/filler interaction. This review is based on the latest development of interfacial crystallization in polymer/filler composites and will be organized as follows. The structural/morphological features of various interfacial crystallization fashions are described first. Subsequently, various influences on the final structure/morphology of hybrid crystallization and the nucleation and/or growth mechanisms of crystallization behaviors at polymer/filler interface are reviewed. Then recent studies on interfacial crystallization induced interfacial enhancement ascertained by different research methodologies are addressed, including a comparative analysis to highlight the positive role of interfacial crystallization on the resultant mechanical reinforcement. Finally, a conclusion, including future perspectives, is presented.