Advance Oxidation Process (AOP) of Bisphenol A Using a Novel Surface-Functionalised Polyacrylonitrile (PAN) Fibre Catalyst

Open access articleBisphenol A (BPA) is a well-known endocrine disruptor in the environment which is not readily oxidised during wastewater treatment at Municipal Authorities. The aim of this work is to evaluate the environmental value of the wastewater treatment of a novel heterogeneous oxidation catalyst by means of the degradation of BPA, avoiding sewage sludge and its post-treatments. A surface-functionalised polyacrylonitrile (PAN) mesh has been produced by reaction of the cyano group of PAN with hydrazine and hydroxylamine salts. This surface-functionalised PAN is then exposed to iron (III) salt solution to promote the ligation of Fe(III) to the functional groups to form the active catalytic site. The experiments were set up in two different batch reactors at laboratory scale at different temperatures and initial pH. The degradation of BPA was detected by measuring the absorbance of BPA in Reverse Phase High Performance Liquid Chromatography at 280 nm. A total elimination of 75 ppm of BPA in less than 30 min was achieved under 300 ppm H2O2 , 0.5 g PAN catalyst, initial pH 3 and 60 ◦C. Almost no adsorption of BPA on the catalyst was detected and there was no significant difference in activity of the catalyst after use for two cycles

Polymer-drug nanoconjugate – an innovative nanomedicine: challenges and recent advancements in rational formulation design for effective delivery of poorly soluble drugs.

The published manuscript is available at EurekaSelect via - See more at: http://dx.doi.org/10.2174/2211738504666160213001714Abstract Background: Over the last four decades, the use of water soluble polymers in rational formulation design has rapidly evolved into valuable drug delivery strategies to enhance the safety and therapeutic effectiveness of poorly soluble drugs, particularly anticancer drugs. Novel advances in polymer chemistry have provided new generations of well defined polymeric architectures for specific applications in polymer-drug conjugate design. However, total control of crucial parameters such as particle size, molecular weight distribution, polydispersity, localization of charges, hydrophilic-lipophilic balance and non site-specific coupling reactions during conjugation has been a serious challenge. Objective: This review briefly describes the current advances in polymer-drug nanoconjugate design and various challenges hindering their transformation into clinically useful medicines. Method: Existing literature was reviewed. Results: This review provides insights into the significant impact of covalent and non-covalent interactions between drug and polymer on drug loading [or conjugation] efficiency, conjugate stability, mechanism of drug release from the conjugate and biopharmaceutical properties of poorly soluble drugs. The utility values and application of Quality by Design principles in rational design, optimization and control of the Critical Quality Attributes [CQA] and Critical Process Parameters [CPP] that underpin the safety, quality and efficacy of the nanoconjugates are also presented. Conclusion: It was apparent that better understanding of the physicochemical properties of the nanoconjugates as well as the drug-polymer interaction during conjugation process is essential to be able to control the biodistribution, pharmacokinetics, therapeutic activity and toxicity of the nanoconjugates which will in turn enhance the prospect of successful transformation of these promising nanoconjugates into clinically useful nanomedicines

Reduction of Legionella spp. in water and in soil by a citrus plant extract vapor

Legionnaires disease is a severe form of pneumonia caused by Legionella spp. often isolated from environmental sources including soil and water. Legionella spp. are capable of replicating intracellularly within free living protozoa, once this has occurred Legionella spp. is particularly resistant to disinfectants. Citrus Essential Oils (EOs) vapours are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml(-1) on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapour against Legionella spp. in water and in soil systems. Reductions of viable cells of Legionella pneumophila, Legionella longbeachae, Legionella bozemanii and intra-amoebal culture of Legionella pneumophila (water system only), were assessed in soil and in water after exposure to a citrus EO vapour at concentrations ranging from 3.75 mg/l air to 15g/l air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapour) was conducted in water and GC-MS analysis of the antimicrobial components (linalool, citral and β-pinene) determined. There was up to a 5 log cells ml(-1) reduction in Legionella spp. in soil after exposure to the citrus EOs vapour (15 mg/l air). The most susceptible strain in water was L. pneumophila with a 4 log cells ml(-1) reduction after 24 hrs via sintering (15 g/l air). Sintering the vapour through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapour may go some way in controlling Legionella spp. from environmental sources

Multi-material additive manufacturing of low sintering temperature Bi2Mo2O9 ceramics with Ag floating electrodes by selective laser burnout

Additive manufacturing (AM) of co-fired low temperature ceramics offers a unique route for fabrication of novel 3D radio frequency (RF) and microwave communication components, embedded electronics and sensors. This paper describes the first-ever direct 3D printing of low temperature co-fired ceramics/floating electrode 3D structures. Slurry-based AM and selective laser burnout (SLB) were used to fabricate bulk dielectric, Bi2Mo2O9 (BMO, sintering temperature = 620–650°C, εr = 38) with silver (Ag) internal floating electrodes. A printable BMO slurry was developed and the SLB optimised to improve edge definition and burn out the binder without damaging the ceramic. The SLB increased the green strength needed for shape retention, produced crack-free parts and prevented Ag leaching into the ceramic during co-firing. The green parts were sintered after SLB in a conventional furnace at 645°C for 4 h and achieved 94.5% density, compressive strength of 4097 MPa, a relative permittivity (εr) of 33.8 and a loss tangent (tan δ) of 0.0004 (8 GHz) for BMO. The feasibility of using SLB followed by a post-printing sintering step to create BMO/Ag 3D structures was thus demonstrated

Microwave dielectric measurements of fibrous catalyst using transmission line technique in the frequency range of 1-4 GHz

Materials performance at microwave frequencies has generated a wide interest in recent years for commercial and industrial purposes. However, the interaction between microwave energy and iron compounds is an area where further characterization work is required. The article presents a novel optimized analytical-numerical method for conversion of smoothed transmission scattering (S21) parameters to complex permittivity. The measurement method was validated and subsequently used to characterize the dielectric properties of modified polyacrylonitrile catalyst powder incorporating ligated iron cations. The result is compared to other published iron catalyst materials measured in the same frequency range of 1 to 4 GHz

Field trial of an ion exchange based metal removal technology in the treatment of mine waters

A pilot scale field trial for a novel metal removal technology in the treatment of mine waters was performed using mine water from White Tip, part of the former Snailbeach lead mine in Shropshire, United Kingdom (UK). The water is circum-neutral pH and contains elevated zinc (Zn), lead (Pb) and cadmium (Cd). The novel treatment process is based on ion exchange (IE) using a bespoke mesh in a rotating disc reactor. Effects of process parameters such as regeneration of mesh, residence time (RT) and rotation speed (RS) of the discs were investigated. Treatment performance of the system was consistent for the removal of Zn and Pb whereas for Cd it was more variable. The order of removal efficiencies was Pb (75.04%) > Zn (64.18%) > Cd (22.37%). Accordingly, 4.15 kg of Zn, 5.22 g of Pb and 5.55 g Cd were removed from 131.46 m3 of mine water in 170 days. Amongst the other metals / metalloids removed by the system include iron (Fe), aluminium (Al), manganese (Mn), copper (Cu), barium (Ba), arsenic (As), nickel (Ni), boron (B), chromium (Cr) and small amounts of sodium (Na), potassium (K) and strontium (Sr). Similarly, non-metallic water quality parameters removed by the system include acidity, suspended solids (SS), alkalinity and small amounts of nitrate (NO3-N) and total anions. The system generated a small amount of ammoniacal nitrogen (NH3-N), sulfate (SO4-S) and hardness. An average rise of pH by ~0.5unit in treated water was observed. Performance of the treatment system was not significantly affected by the regeneration of the mesh and RS of the discs. The treatment process was not affected by the temperature variations in the range of 0.7°C to 20°C. Maximum removals of metals were observed when RT≥1.33 hours

Quantification of in situ granulation-induced changes in pre-compression, solubility, dose distribution and intrinsic in vitro release characteristics of ibuprofen–cationic dextran conjugate crystanules

The direct effect of intermolecular association between ibuprofen and diethylaminoethyl dextran (Ddex) and the novel ‘melt-in situ granulation–crystallization’ technique on the solubility, dose distribution, in vitro dissolution kinetics and pre-compression characteristics of the ibuprofen–Ddex conjugate crystanules have been investigated using various mathematical equations and statistical moments. The research intention was to elucidate the mechanisms of ibuprofen solubilization, densification and release from the conjugate crystanules as well as its dose distribution in order to provide fundamental knowledge on important physicochemical, thermodynamic and system-specific parameters which are key indices for the optimization of drug–polymer conjugate design for the delivery of poorly soluble drugs. The process of melt-in situ-granulation–crystallization reduced the solubility slightly compared with pure ibuprofen, however, the ibuprofen–Ddex conjugate crystanules exhibited increased ibuprofen solubility to a maximum of 2.47 Â 10 À1 mM (at 1.25 Â 10 À4 mM Ddex) and 8.72 Â 10 À1 mM (at 6.25 Â 10 À4 mM Ddex) at 25 and 37 C, respectively. Beyond these concentrations of Ddex ibuprofen solubility decreased steadily due to stronger bond strength of the conjugate crystanules. The enthalpy– entropy compensation plot suggests a dominant entropy-driven mechanism of solubilization. In the same vein, the addition of Ddex increased the rate and extent of in vitro ibuprofen release from the conjugate crystanule to 100% within 168 h at Ddex concentration of 1.56 Â 10 À4 mM, followed by a decrease with Ddex concentration. The conjugate crystanules exhibited controlled and extended- complete release profile which appeared to be dictated by the concentration of the Ddex and its strong affinity for ibuprofen. A comparison of the real experimental with the predicted data using artificial neural network shows excellent correlation between solubility and dissolution profiles (average error = 0.2348%). Heckel, Kawakita, Cooper–Eaton and Kuno equations were employed to determine the mechanism of densification during tapping process. Ddex in the crystanules consistently improved particle rearrangement in the order of 2.5–7 folds compared with pure ibuprofen and stabilized ibuprofen against fragmentation during tapping process. Primary and secondary particle rearrangements were the prominent mechanisms of densification while deformation and fragmentation did not occur. Lower concentrations of Ddex below its critical granular concentration (<6.25 Â 10 À4 mM) hindered plastic deformation and fragmentation, however, the summation of primary and secondary rearrangement parameters was greater than unity suggesting that the overall rearrangement of the conjugate crystanules cannot be explained exclusively by these two steps. This study has demonstrated the formulation of a novel ibuprofen–polymer conjugate which exhibited improved dose distribution and pre-compression characteristics as well as controlled and extended-complete release profiles – a potential drug delivery strategy for poorly soluble drugs

Additive Manufacturing of Next Generation Dielectric Metamaterials for High Frequency Applications

This research project will assess the feasibility of introducing novel metamaterials through real integration of advanced manufacturing technologies and material sciences to produce complex structures with characteristics that are not generally offered by existing materials. This could offer a radically new way of designing and manufacturing electronic components with tailored performance characteristics. To achieve this multidisciplinary project, electronic components or substrates comprising of selected ceramic and/or metal meta-atoms of various sizes and shapes will be formulated, fabricated, processed, characterised and their electronic properties measured at high frequencies

Field Assisted Processing of 3D Printed Ceramics

Fabrication of complex ceramic components involves multiple steps, often is labour & energy intensive. 3D printing of ceramics and their sintering through the application of external fields could pave the way for solving these issues. In this work, the combination of Additive Manufacturing (AM) along with Field Assisted Sintering Techniques (FAST) were employed to manufacture functional ceramics suitable for electronic, communication and healthcare sectors. This poster highlights some of the recent advances

Multi-material additive manufacture and microwave-assisted sintering of a metal/ceramic metamaterial antenna structure

Multi-material metal/ceramic 3D structures comprising of metallic silver and ultra-low sintering temperature silver molybdenum oxide ceramics, have been additively manufactured and hybrid densified using microwave-assisted sintering for the first time. Optimum densification conditions at 440°C / 1 hour, resulted in relative permittivity, εr = 10.99 ± 0.04, dielectric losses, tanδ = 0.005 ± 0.001 and microwave quality factor, Q × f = 2597 ± 540 GHz. Applying 2 kW microwave energy at 2.45 GHz for 60 minutes, was proven sufficient, to densify the metallic Ag infilling electrodes, without causing any macroscopic defects. A fully functional multi-layered antenna structure with a metamaterial artificial magnetic conductor was designed, dual-printed and densified, to showcase the potential of combining multi-material additive manufacturing with microwave-assisted sintering.</p