Mesoporous Materials for Metal-Laden Wastewater Treatment

Rapid technological, industrial and agricultural development has resulted in the release of large volumes of pollutants, including metal ions, into the environment. Heavy metals have become of great concern due to their toxicity, persistence, and adverse effects caused to the environment and population. In this regard, municipal and industrial effluents should be thoroughly treated before being discharged into natural water or used for irrigation. The physical, chemical, and biological techniques applied for wastewater treatment adsorption have a special place in enabling effective pollutant removal. Currently, plenty of adsorbents of different origins are applied for the treatment of metal-containing aqueous solution and wastewater. The present review is focused on mesoporous materials. In particular, the recent achievements in mesoporous materials' synthesis and application in wastewater treatment are discussed. The mechanisms of metal adsorption onto mesoporous materials are highlighted and examples of their multiple uses for metal removal are presented. The information contained in the review can be used by researchers and environmental engineers involved in the development of new adsorbents and the improvement of wastewater treatment technologies.

Highly Hydrophobic Cotton Fabrics Modified by Poly(methylhydrogen)siloxane and Fluorinated Olefin: Characterization and Applications

Highly hydrophobic cotton fabrics were obtained with poly(methylhydrogen)siloxane (PMHS) and a further fluorinated olefin modification. The chemical structures and microstructures of PMHS-modified cotton fabrics were characterized, and application of the resultant cotton fabrics in stain resistance and oil–water separation was demonstrated. PMHS chains with very low surface energy were grafted onto cotton fabric by the dehydrogenation reaction between –Si–H of PMHS and –OH groups of cotton fabric at room temperature. The water contact angle of PMHS-modified cotton fabric was 141.7°, which provided the modified cotton fabric with good stain resistance to waterborne pollutants. The separation efficiency of diesel from water was higher than 92% for 20 repeatable separation cycles. A further improvement in stain resistance to oil was also demonstrated by a further addition reaction of 1H,1H,2H-perfluoro-1-decene with PMHS-modified cotton fabric.

Palladium nanoparticles-anchored dual-responsive SBA-15-PNIPAM/PMAA nanoreactor: a novel heterogeneous catalyst for a green Suzuki–Miyaura cross-coupling reaction

Palladium nanoparticles-anchored dual-responsive SBA-15-copolymer nanoreactor was developed as a novel heterogeneous catalyst for green Suzuki–Miyaura cross-coupling reaction.

Hexadecyltrimethylammonium Bromide Surfactant-Supported Silica Material for the Effective Adsorption of Metanil Yellow Dye

The adsorption behavior of an organic dye, metanil yellow (My), from water using micro-nano silica particles (MNSPs) was investigated. MCM-41-like (Mobil Composition of Matter No. 41) MNSPs were synthesized using tetraethoxy orthosilicate as a silica source and hexadecyltrimethylammonium bromide (CTAB) as a surfactant under basic conditions. Comparative studies were performed to assess the adsorption behaviors of the organic dye using the as-synthesized MCM-41 before the removal of CTAB and MCM-41, either after one, two, and three times of chemical etching or after calcination. My was adsorbed more effectively from water on the as-synthesized MCM-41 without the removal of the surfactant than on MCM-41 after the removal of the surfactant by chemical etching or calcination. In addition, MCM-41 after removing the surfactant by one-time chemical etching in the presence of hydrochloric acid also showed better adsorption of My from water than MCM-41 after removing the surfactant by further two and three times of chemical etching or calcination. For comparison, other kinds of dye molecules with different chemical structures such as methylene blue (Mb) and rhodamine B (Rb) were also used to check the possibility of adsorption of various dyes by the CTAB-supported MNSPs. To better understand the reason behind the adsorption phenomena, detailed studies on the kinetics and thermodynamics of adsorption of the MNSPs were performed. Excellent adsorption of My was observed at concentrations up to 100 mg L^-1 at 25 °C, whereas the adsorption was lower at higher concentrations of the My dye. Furthermore, enhanced My dye adsorption was observed at higher concentrations by increasing the adsorption temperature. It can be concluded that the MNSPs exhibited efficient adsorption of My, when the MNSPs are used without the removal of the surfactant and any further modifications, suggesting that the surfactant played key roles in the effective adsorption of the anionic dye. The as-synthesized MCM-41 was, however, not a good adsorbent for cationic dyes such as Mb and Rb.

Functionalized mesoporous silica nanoparticles and biomedical applications

Since the first report in early 1990s, mesoporous silica nanoparticles (MSNs) have progressively attracted the attention of scientists due to their potential applications in physic, energy storage, imaging, and especially in biomedical engineering. Owning the unique physiochemical properties, such as highly porosity, large surface area and pore volume, functionalizable, tunable pore and particle sizes and biocompatibility, and high loading cavity, MSNs offer efficient encapsulation and then controlled release, and in some cases, intracellular delivery of bioactive molecules for biomedical applications. During the last decade, functionalized MSNs that show respond upon the surrounding stimulus changes, such as temperature, pH, redox, light, ultrasound, magnetic or electric fields, enzyme, redox, ROS, glucose, and ATP, or their combinations, have continuously revolutionized their potential applications in biomedical engineering. Therefore, this review focuses on discussion the recent fabrication of functionalized MSNs and their potential applications in drug delivery, therapeutic treatments, diagnostic imaging, and biocatalyst. In addition, some potential clinical applications and challenges will also be discussed.