Current Materials Science - Volume 13, Issue 2, 2020

The manuscript discusses the role of polysaccharides and their derivatives in the removal of metal ions from industrial wastewater. Quick modernization and industrialization increase the amount of various heavy metal ions in the environment. Heavy metals can cause various diseases in humans and also drastic environmental hazards. In this review, the recent advancement for the adsorption of heavy metal ions from wastewater by using different methods has been studied. Various natural polymers and their derivatives act as effective adsorbents for the removal of heavy metal ions from the wastewater released from the industries and the treated water released into the environment can decrease the probability of diseases in humans and environmental hazards. From the literature surveys, it was concluded that the removal of heavy metal ions from industrial wastewater is beneficial for humans as well as for environment. Graft copolymers act as the most efficient adsorbents for the removal of heavy metal ions and most of these follow the pseudo-first-order and pseudo-second-order model of kinetics.

Background: Tailings produced from iron ore smelting processes have increased dramatically in recent decades. The storage of tailings not only needs high cost, but also causes a great environmental and safety hazard. Therefore, it is urgent to use new technologies to comprehensively utilize tailings. Methods: The phases and micro-morphology of the baking-free bricks were investigated by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The optimal components and preparation parameters of the baking-free bricks were determined by controlling the ratio of the raw materials and forming pressure. The compressive strength and density of the baking-free bricks were analyzed by controlling the forming pressure and curing time. Results: The optimal components of the baking-free bricks are 65wt.% tailings, 5wt.% titanium gypsum, 17wt.% slag, 5wt.% acetylene sludge, 8wt.% waste brick powder. The optimal forming pressure is 10MPa. 28 d compressive strength and density of the baking-free bricks reach 19.8 MPa and 1622.92 kg.m^-3, respectively. Irregular particles and ettringite (Aft) nanorods in the baking-free bricks contribute to the improvement of the compressive strength and compactness of the tailing bricks. Conclusion: Baking-free bricks were successfully prepared from iron ore tailings by pressure forming method and exhibited great application promising in the construction field.

Background: Innovative cooling technology is required in every field of life, ranging from satellite to terrestrial applications. A novel heat rejection system is of great concern for space applications. Futuristic applications in heat pipe will involve composite structures in various ways as they offer flexibility in design with their inherent advantage of being lightweight. However, it remains a challenge to join a composite structure with metals. This study investigates the effect of a composite section in the adiabatic region of the heat pipe and also proposes a novel approach to join metals with a composite structure. Methods: A flexible composite tube, such as carbon fiber, reinforced thermoplastics to make the adiabatic section. This section is adhesively bonded with the metal tubes, i.e., evaporator and condenser section. The inherent roughness of the metal tube makes the first layer for mechanical interlocking, followed by adhesive bonding. Results: The effect of adiabatic, condenser, and evaporator length, for a normal vs. composite heat pipe, on specific thermal conductivity is evaluated. Conclusion: The numerical studies confirm that the use of composite material for the adiabatic section improves the performance of the heat pipe. It is proposed to use reinforced thermoplastic as the material for the adiabatic section.

Background: The composite materials are more efficient and more resistant compared to so-called traditional materials. The application of continuous and variable forces modifies the properties of the materials, and generates the formation of cracks which lead to the rupture of structures. Objective: The objective of this work is to study the reliability and the origin of the resistance of each fiber-matrix interface of the two hybrid composite materials studied. Methods: In this study, the genetic algorithm is based on Weibull’s probabilistic approach to calculate the damage to the interface and also on the Cox model to find and initialize the different values used in simulation model. Results: The results obtained by genetic modeling, have shown that the hybrid Carbon High Modulus (HM)/Basalt/Polyester composite is the most resistant to the mechanical stresses applied comparing with that of Carbon High Strength (HS)/Basalt/Polyester. These results were confirmed by the level of damage to the interface found for the two materials studied and that the interface shear damage of the hybrid Carbon HM/Basalt/Polyester composite is much lower by 13% compared to that of Carbon HS/Basalt/Polyester. Conclusion: The calculations are in good agreement with the analytical results of Cox, where he demonstrated that Young’s modulus of the fibers has an important influence on the shear strength of the fiber/matrix interface of composite materials.

Background: The objective of this research is to evaluate the tensile, impact and flexural properties of flax fiber and basalt powder filled polyester composite. Flax fiber is one of the predominant reinforcement natural fiber which possess good mechanical properties and addition of basalt powder as a filler provides additional support to the composite. Methods: The Composites are prepared using flax fiber arranged in 10 layers with varying weight percentage of the basalt powder as 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.% and 30 wt.% respectively. Results: From the results it is inferred that the composite combination 10 Layers of flax / 5 wt.%, basalt Powder absorbs more tensile load of 145 MPa. Also, for the same combination maximum flexural strength is about 60 MPa. Interestingly in the case of impact strength more energy was absorbed by 10 layers of flax and 30 wt.% of basalt powder. In addition, the failure mechanism of the composites also discussed briefly using SEM studies. Conclusion: Flax fiber reinforced basalt powder filled polyester composites are successfully fabricated by compression moulding method. Tensile, Flexural and Impact strength gets increased by varying the flax fiber weight percentage.

Background: Fe3o4 nanoparticles have great potential in different biomedical applications. The study of the interaction of bare, and capped Fe3O4 nanoparticles with common blood proteins is a field of interest for understanding the underlying mechanism and biocompatibility. Objective: This work aims at studying the nature of binding of bare, citrate functionalised and bovine serum albumin coated Fe3O4 nanoparticles (Fe3O4NPs, CFe3O4NPs and BFe3O4NPs) with human hemoglobin (Hb), and their instantaneous effect on amino acid group, heme group and secondary structure of Hb. Methods: Nanoparticles were prepared by the chemical route and characterised by TEM, XRD and UV-Visible and FTIR spectroscopy. UV-visible absorbance and fluorescence emission/ excitation spectroscopy and circular dichroism were performed to study the interaction of nanoparticles with Hb. Results: UV-visible absorbance spectroscopy showed no blue or red shift of absorption peaks. Benesi-Hildebrand curves for the amino acid band and soret band of Hb absorbance spectrum were straight lines with positive intercepts; apparent binding constants and Gibbs free energy change were within a moderate level; they were larger for amino acid band in the presence of CFe3O4NPs, and for soret band in the presence of Fe3O4NPs, but noticeably small for both bands in the presence of BFe3O4NPs. Fluorescence emission/excitation spectra showed no noticeable shift of emission/excitation peak position of Hb in the presence of the three nanoparticles. Multiple peak fitting, done for the L-peak of the excitation spectrum of Hb, showed a major increase in the percentage of peak area of Tyr in the presence of CFe3O4NPs. Circular dichroism measurement showed that CFe3O4NPs, Fe3O4NPs and BFe3O4NPs reduced the α-helix content of Hb in decreasing order. Conclusion: Ground state complex formation of human hemoglobin with the studied nanoparticles with 1:1 stoichiometric ratio is suggested. Moreover, it has been observed that CFe3O4NPs may have a stronger interaction with the amino acid group while bare Fe3O4NPs may have a stronger interaction with the heme group of Hb. Hinderance of the energy transfer from tyrosine to tryptophan of Hb in the presence of CFe3O4NPs is also suggested. CFe3O4NPs may also have some effect on the secondary structure of Hb as indicated through reduction of the α-helix content. BFe3O4NPs have shown very weak interaction with Hb in the UV-visible absorbance spectroscopy, fluorescence emission/excitation spectroscopy and circular dichroism experiment.