Incorporation of nanoparticles of titanium dioxide into thermoplastic textiles

The incorporation of nanoparticles (NPs) into the surfaces of materials has received significant attention, especially in the area of textiles for self-cleaning. The sphericity and fast oxidation of metallic NPs when exposed to atmosphere are factors that can complicate incorporation into textile substrates. Using unique photocatalytic properties to decompose bacteria cells, NPs of titanium dioxide (TiO2) are widely known as a common antimicrobial agent. The current research focuses on an innovative and novel coating process, where NPs of TiO2 have been incorporated by embedding on single-side of a textile fabric surface, while retaining exposure of the NPs to photon sources. This technique was linked with the surface modification of textiles by thermal heating of the surface, which initiated the reduction of the fabrics elastic modulus by surface-softening, then embedding NPs into the heated zone of the textile surface. The NPs were sufficiently embedded for durable adherence to the fabric surface, while retaining an optimum exposure to photon sources. Thermoplastic textiles, with a viscoelastic stage, permit recovery of its surface when heated below its melting temperature, Tm and were found to be an ideal material for this method of incorporation. The elastic modulus of polyethylene terephthalate (PET) textiles was investigated by thermodynamic experimental techniques, where the critical data was employed with two variant theories of contact mechanics. The study has found that embedding of NPs was better described by the JKR model due to its higher sensitivity to the reduction of the stiffness, the size of the NPs and the type of textile. Experimental rigs initiated the activation process for adherence of NPs to single-side of PET, cellulose acetate (CA) and acrylic thermoplastic polymer textiles. Analytical techniques, such as scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were employed to investigate the effective processing parameters of rigs. These properties included: quantitative and qualitative distribution of NPs on surfaces; durability of NPs to textiles; the textile transformation temperatures; and thermo-elastic responses. Film formation by agglomeration of NPs on textiles was noted where a higher concentration of TiO2 was applied. A Pull-Off technique was employed for the measurement of durability of NPs to textiles presenting insufficient quantities of Ti on the adhesive-tapes for a conclusive outcome. Mapping by EDS techniques was a method of quantifying the surface coverage of NPs on PET, with inconclusive outcomes. A standardised laundering procedure applied to textiles was a method of testing the durability of NPs to textiles, where an AAS instruments was sued to quantify the content of TiO2 (μg/cm2). The best optimised textile of PET was achieved for 76% retention of TiO2 between 1 and 40 laundering cycles. Empirical models were derived for the prediction of the optimum parameters for processing textiles by automatic rigs, and the prediction of TiO2 (μg/cm2) on PET. Automatic rigs were suitable to processing of thermoplastic textiles with NPs on single-side of its surface, and achieving increased retention where a reduction of the applied concentration and the higher surface heating was initiated. The outcomes of this study solve a major issue in the area of incorporation of NPs into textiles, by embedding NPs with high durability, and still exposing them for maximum antimicrobial abilities. The process has the potential for employment in the textile industry, for a cost effective method of preparing thermoplastic textiles providing efficient distribution and adherence of NPs on its surface, using inexpensive binding materials and processes

Standardization of research methods employed in assessing the interaction metallic-based nanoparticles and the blood-brain barrier: present and future perspectives

Treating diseases of the central nervous system (CNS) is complicated by the presence of the blood-brain barrier (BBB), a semipermeable boundary layer protecting the CNS from toxins and homeostatic disruptions. However, this layer also excludes almost 100% of therapeutics, impeding the treatment of CNS diseases. The advent of nanoparticles, in particular metallic-based nanoparticles, presents the potential to overcome this barrier and transport drugs into the CNS. Recent interest in metallic-based nanoparticles has generated an immense array of information pertaining to nanoparticles of different materials, sizes, morphologies, and surface properties. Nanoparticles with different physico-chemical properties lead to distinct nanoparticle-host interactions; yet, comprehensive characterization is often not completed. Similarly, in vivo testing has involved a mixed evaluation of parameters, including: BBB permeability, integrity, biodistribution, and toxicity. The methods applied to assess these parameters are inconsistent; this complicates the comparison of different nanoparticle-host system responses. A systematic review was conducted to investigate the methods by which metallic-based nanoparticles are characterized and assessed in vivo. The introduction of a standardized approach to nanoparticle characterization and in vivo testing is crucial if research is to transition to a clinical setting. The approach suggested, herein, is based on equipment and techniques that are accessible and informative to facilitate the routine incorporation of this standardized, informative approach into different research settings. Thorough characterization could lead to improved interpretation of in vivo responses, which could clarify nanoparticle properties that result in favorable in vivo outcomes whilst exposing nanoparticle-specific weaknesses. Only then will researchers successfully identify nanoparticles capable of delivering life-saving therapeutics across the blood-brain barrier

Highly selective trace ammonium removal from dairy wastewater streams by aluminosilicate materials

Water is a key solvent, fundamental to supporting life on earth. It is equally important in many industrial processes, particularly within agricultural and pharmaceutical industries, which are major drivers of the global economy. The results of water contamination by common activity in these industries is well known and EU Water Quality Directives and Associated Regulations mandate that NH4+ concentrations in effluent streams should not exceed 0.3 mg L−1, this has put immense pressure on organisations and individuals operating in these industries. As the environmental and financial costs associated with water purification begin to mount, there is a great need for novel processes and materials (particularly renewable) to transform the industry. Current solutions have evolved from combating toxic sludge to the use of membrane technology, but it is well known that the production of these membrane technologies creates a large environmental footprint. Zeolites could provide an answer; their pore size and chemistry enable efficient removal of aqueous based cations via simple ion exchange processes. Herein, we demonstrate efficient removal of NH4+ via both static and dynamic methodology for industrial application. Molecular modelling was used to determine the cation–framework interactions which will enable customisation and design of superior sorbents for NH4+ capture in wastewater

Metal–organic material polymer coatings for enhanced gas sorption performance and hydrolytic stability under humid conditions

Physisorbent metal–organic materials (MOMs) have shown benchmark performance for highly selective CO2 capture from bulk and trace gas mixtures. However, gas stream moisture can be detrimental to both adsorbent performance and hydrolytic stability. One of the most effective methods to solve this issue is to transform the adsorbent surface from hydrophilic to hydrophobic. Herein, we present a facile approach for coating MOMs with organic polymers to afford improved hydrophobicity and hydrolytic stability under humid conditions. The impact of gas stream moisture on CO2 capture for the composite materials was found to be negligible under both bulk and trace CO2 capture conditions with significant improvements in regeneration times and energy requirements