Volume 31, Issue 3

Porous silicon (PSi) has emerged over the past decade as a promising biomaterial for nanomedicine in general and cancer nanomedicine in particular. PSi offers a unique combination of properties, including large surface area and porous volume, biocompatibility, degradability in vivo into non-toxic silicic acid species, as well as its wealth of intrinsic optical properties (e.g., luminescence, photonic). This arsenal of properties together with the ability to tailor the PSi nanostructure and surface characteristics have led to an immense research effort directed at the development of PSi-based platforms for biomedical applications. After a brief introduction of the biology of cancer and currently practiced therapies, we provide an updated review of the progress of PSi-based platforms for cancer therapy and imaging.

The low-temperature Fischer-Tropsch (LTFT) process aims to produce heavy cuts such as wax and diesel. For many years, there have been studies and improvements on the LTFT process to make the existing reactors more efficient. Recent studies have proposed innovative configurations such as monolithic loop and membrane reactors as well as microchannel reactor, which improved the performance of LTFT synthesis. This persuades us to update the existing knowledge about the available reactors. Some fundamental features of the current reactors, which belong to the classes of conventional reactors (fixed-bed reactors and slurry reactors) and innovative reactors, are discussed to assist the selection of the most efficient reactors specifically for heavy-cuts production. Published experimental and theoretical works with respect to developments in reactor technology and significant advances in catalysis (such as using structured packing, foams, and knitted wire as catalyst supports due to their excellent radial mixing properties) of the FT process are analyzed and discussed. Consequently, it is shown that the LTFT innovative reactors have higher CO conversions and selectivity of desired heavy cuts. Furthermore, the place of innovative reactors among conventional reactors in terms of effective process parameters on the product distribution has been estimated.

Cationic polyelectrolytes are water-soluble polymers bearing positive ionic groups along the backbone or in side chains. These cationic polymers are synthesized by free radical polymerization of acrylamide and their derivatives by the copolymerization method, which includes solution, precipitation, and emulsion techniques. The Mannich reaction is another important method by which the cationic polymers can be processed. In this review paper, the preparation methods, interaction mechanisms of these polymers, and their popular industrial applications are summarized. These polymers open a lot of applications in different fields such as paper-making processes, water and wastewater treatment, oil and drilling industries, mineral separation, paint and food industries, cosmetics, and pharmacy. In addition, these polymers are widely used as flocculants and rheology control agents. These polymers are especially employed in oil field operations as viscosity control agents for enhanced oil recovery, drilling fluid additives, and also for modifying flow and stability properties of aqueous solutions and gels. They are used as super-plasticizers, which affect the rheological properties of dense cement suspensions. Mining processes also benefit from the use of acrylamide derivative polymers to flocculate solids in aqueous dispersions. The cationic polymers may interact with different components in the system such as inorganic/organic particles in aqueous dispersions in several ways, which may result in the stability or instability of dispersion. The particles can be destabilized through three different main mechanisms which promote flocculation: polymer bridging, charge neutralization, and polymer adsorption.

Advanced oxidation processes (AOPs) are commonly used for treating recalcitrant wastewater with varying degree of efficiency, depending on several operating parameters. In this review, a comparative study among selected AOPs integrated with ultraviolet (UV) (UV/Fenton, UV/H 2 O 2 , UV/O 3 , UV/TiO 2 , UV/persulfate, UV/H 2 O 2 /O 3 , and UV/TiO 2 /H 2 O 2 ) was conducted. The cost implication, changes in kinetics, changes in reaction rates, and effects of various parameters such as type of contaminants, pH, catalyst loading concentration of oxidants, and type of UV light are explained and concluded in this paper. From this review, it is concluded that UV-integrated AOPs are efficient for wastewater treatment. However, a few aspects must be considered including process scale-up, kinetics of combined processes, reactor configuration, modeling of a system, and optimization of operating parameters to enhance the process efficiency.