Textile-based cyanobacteria biocomposites for potential environmental remediation applications

Microalgae and cyanobacteria are effective platforms for environmental remediation (phycoremediation), particularly of air and water. There is limited scope to deploy suspension cultures due to space, cost and maintenance challenges—driving an imperative towards biofilm-based treatment systems; however, these systems are ill-equipped for rapid and mobile deployment. In this study we explored the main technical challenges to developing cheap, accessible and low-maintenance engineered biofilm systems (biocomposites) comprising cyanobacteria (Synechococcus elongatus) immobilised to a range of textiles (n = 4) by natural or synthetic latex binders (n = 16), chitosan or shellac. Biocomposite viability (measured as net CO2 uptake) was assessed over 20 days in semi-batch trials. No maintenance was required during this period as the humidity within the reactor was sufficient to support metabolism. Two commercial natural latex binders (AURO 320 and 321) supported strong growth within the biocomposite, outperforming suspension controls. There was variation in textiles performance, with an 80/20 polyester-cotton blend performing most consistently. Biocomposite formulation was varied in terms of binder solids content and cell loading rate, with 5% solids and 2.5% cell loading the most effective combination. We demonstrate the technical feasibility of fabricating functional textile-based cyanobacteria biocomposites and discuss this within the context of developing decentralised wastewater treatment services.

Use of Mass Spectrometry for Identification and Quantitation of Tensoactive Agents in Synthetic Latex Samples

<p>Separation, characterization and quantification of surfactants in different matrices is important due to the continuously increasing use of these products in industry and the adverse effects of their degradation products in the environment. However, surfactant separation and identification is a real challenge because of the wide chemical diversity of this type of compounds. In this report, HPLCUV or HPLC-Evaporative light scattering detector combined with electrospray ionization (infusion)-high resolution mass spectrometry (ESI-HRMS) was used for the study of main components in four commercial surfactants. In a second stage, size-exclusion chromatography and off-line ESI-MS were combined for quantification of surfactants in a synthetic latex sample by standard-additions method. This strategy allowed unambiguous determination of the structure of tensoactive agents in commercial products, and further use of obtained data for the selective determination of surfactants in the complex polymeric matrix of an industrial latex.</p>

Chemical Resistance of Concrete-Polymer Composites – Comparison Based on Experimental Studies

One of the main advantage of Concrete-Polymer Composites (C-PC) in relation to Cement Concrete called Ordinary Concrete is its chemical resistance. There is no European standard for testing the chemical resistance of cement based concretes and C-PC. American standards ASTM provide varied concrete tests depending on exposure conditions and mechanisms of destruction of concrete structures but there is a lack of clear criteria for the evaluation of research results by these methods. There are also requirements for monolithic floors chemical resistance - ASTM C722-04 and the requirements of the standard EN 1504-2, but they involve coating materials and cannot be directly applied to the cement concrete and C-PC. The paper presents the experimental studies of chemical resistance of C-PC in relation to OC. The investigations has been made under different environment conditions. First the samples of Ordinary Concrete (OC), Polymer Concrete (PC-1) based on vinylester resin and Polymer-Cement Concrete (PCC-1) with polyacrylic dispersion used as a co-binder were immersed for a period of time up to 168 days in a distilled water, H2SO4, MgSO4, (NH4)2SO4 and mix of the mentioned. During the storage the pH was controlled. Additionally as a reference the samples were conditioned in a climate chamber (20°C, 60% RH). The compressive strength were tested after defined periods of time. Next experiment was performed on OC and three different PCC – first modified with synthetic latex, second with polyacrylic polymer dispersion and the last with epoxy resin. The samples were immersed in H2SO4 up to 90 days. Compressive strength and mass loss after 30 and 90 days of conditioning were measured. As a reference the water immersion was used. The results obtained in this experimental program showed high chemical resistance of Polymer Concrete. PC samples obtained continuous increases of compressive strength in all examined chemically aggressive environments. It is also confirmed higher chemical resistance of Polymer-Cement Concrete modified with vinylester resin in relation to Ordinary Concrete. The second part of the program showed that the best additive to PCC among poliacrylic dispersion, synthetic latex and epoxy resin was last one. Epoxy modified PCC samples obtained best results both in compressive strength and mass loss tests

The arteries of the brain base in the degu (Octodon degus Molina 1782)

The brain arteries derived from 50 adult degu individuals of both sexes were injected with synthetic latex introduced with a syringe into the left ventricle of the heart under constant pressure. After fixation in 5% formalin and brain preparation, it was found that the sources of the brain&rsquo;s supply of blood are vertebral arteries and the basilar artery formed as a result of their anastomosis. The basilar artery gave rise to caudal cerebellar arteries and then divided into two branches which formed the arterial circle of the brain. The internal carotid arteries in degus, except for one case, were heavily reduced and did not play an important role in the blood supply to the brain. The arterial circle of the brain in 48% of the cases was open from the rostral side. Variation was identified in the anatomy and the pattern of the arteries of the base of the brain in the degu which involved an asymmetry of the descent of caudal cerebellar arteries (6.0%), rostral cerebellar arteries (8%) as well as middle cerebral arteries (12%). In 6% of the individuals double middle cerebral arteries were found. In one out of 50 cases there was observed a reduction in the left vertebral artery and the appearance of the internal carotid artery on the same side. In that case the left part of the arterial circle of the brain was supplied with blood by an internal carotid artery, which was present only in that animal.

Preparation and characterization of oxidized starch-graft-poly(styrene-butyl acrylate) latex via emulsion polymerization

Oxidized starch-graft-poly(styrene-butyl acrylate) [OS-g-P(St-BA)] latex was synthesized by the graft copolymerization of OS with St and n-butyl acrylate (BA) via emulsion polymerization. The graft copolymers were characterized by Fourier transform infrared (FT-IR), transmission electronic microscopy (TEM), dynamic light scattering, thermogravimetry (TG), and differential scanning calorimetry (DSC). The effects of the amount of OS, monomers, and initiator on graft copolymerization were investigated. Under the optimal conditions, the percentage of graft (PG), grafting efficiency (GE), and ζ potential could reach 256.5%, 41.7%, and -30.1 mV, respectively. The results indicated that the OS grafted onto particles greatly enhanced the colloidal stability of latex. The thermal stability properties of OS-g-P(St-BA) were also improved by the addition of OS. The OS-g-P(St-BA) latex may be used to partly replace the conventional synthetic latex for paper coating.

Study on Synthesis of Cationic Polymethyl Acrylate Emulsion

Emulsion copolymerization of methyl acrylate, styrene, acrylamide, acrylonitrile and homemade cationic monomer was studied. A series of clean cationic polymethyl acrylate emulsion were synthesized using no soap emulsion polymerization. Influence of polymerization conditions such as cationic monomer ratio, electrolyte addition amount, the dosage of initiator on synthetic latex performance and the strengthening effect to paper pulp was studied. It was showed by experimental results that sample No.3 which particle size and zeta potential was 0.142 μm and +29.2 mv respectively was the optimal sample latex. When the dosage of latex No.3 was 1.0% to absolute dry pulp, tensile index and ring crush index of paper was increased by 14.6% and 17.8% respectively.

Synthesis and Application of Water-Borne Nontoxic Emulsion from Wasted Polystyrene Foam

A new water-borne nontoxic emulsion of low cost was prepared by using wasted polystyrene foam as elementary component, butyl acrylate (BA), styrene (St) and vinyl acetate (VAc) as modifiers and solvents. Influences of monomers, compounded emulsifier on properties of emulsion were discussed. The optimum process conditions were as follows: m (PSF) : m (monomers) = 1 : 2 , m (sodium dodecyl sulphate) : m (OP-10) = 2 : 1 , m (VAc) : m (St) : m (BA) = 1 : 1 : 2 , and mass fraction of emulsifiers was 3.0 wt% accounting for the total mass of monomers. The synthetic latex with high adhesion strength, pollution-free, low cost and storage stability is applicable to prepare blast furnace slag unburnt bricks, respectively. The properties of the brick sample are better than that of MU 25 of GB 11945-89.