Enhancing chromium removal and recovery from industrial wastewater using sustainable and efficient nanomaterial: A review.

Water contamination can be detrimental to the human health due to higher concentration of carcinogenic heavy metals such as chromium (Cr) in the wastewater. Many traditional methods are being employed in wastewater treatment plants for Cr removal to control the environmental impacts. Such methods include ion exchange, coagulation, membrane filtration, and chemical precipitation and microbial degradation. Recent advances in materials science and green chemistry have led to the development of nanomaterial that possess high specific surface areas and multiple functions, making them suitable for removing metals such as Cr from wastewater. Literature shows that the most efficient, effective, clean, and long-lasting approach for removing heavy metals from wastewater involves adsorbing heavy metals onto the surface of nanomaterial. This review assesses the removal methods of Cr from wastewater, advantages and disadvantages of using nanomaterial to remove Cr from wastewater and potential negative impacts on human health. The latest trends and developments in Cr removal strategies using nanomaterial adsorption are also explored in the present review.

Synthesis, characterization and antifungal potential of titanium dioxide nanoparticles against fungal disease (Ustilago tritici) of wheat (Triticum aestivum L.).

Nanoparticles (NPs) preparation using a green as well as environmentally acceptable processes has achieved a lot of attention in recent decade. The current study compared the synthesis of titania (TiO2) nanoparticles synthesized from leaf extracts of two plant species (Trianthema portulacastrum, Chenopodium quinoa) and traditional approach by chemical preparation. The effects of no calcination on the physical characteristics of TiO2 NPs as well as their antifungal effects were examined and compared with the already reported calcinated TiO2 NPs. The produced TiO2 NPs were evaluated using high-tech techniques such as X-ray diffraction (XRD), scanning electron microscope, energy dispersive spectroscopy (EDX), and elemental mapping. TiO2 NPs prepared by sol-gel technique (T1) and prepared from extractions from leaves of T. portulacastrum (T2), and C. quinoa (T3) were either calcinated or non calcinated and tested against fungal disease (Ustilago tritici) of wheat for antifungal efficacy. The -peak (2θ) at 25.3 was confirmed by XRD to be connected with the anatase (101) form in both cases but before calcination, NPs were lacking the rutile and brookite peaks. The results showed that all types of TiO2 NPs examined had good antifungal activity against U. tritici, but those made from C. quinoa plant extract have good antifungal activity against disease. TiO2 NPs which are produced by the green methods (T2, T3) have the highest antifungal activity (58%, 57% respectively), while minimal activity (19%) was recorded when NPs were synthesized using the sol-gel method (T1) with 25 µl/mL. Non calcinated TiO2 NPs have less antifungal potential than calcined TiO2 NPs. It can be concluded that calcination may be preferred for efficient antifungal activity when using titania nanoparticles. The green technology may be used on a larger scale with less damaging TiO2 NP production and can be utilized against fungal disease on wheat crop to reduce crop losses worldwide.

Effect of Multiple Thermal Cycles on the Microstructure and Mechanical Properties of AISI 1045 Weldments.

AISI 1045 medium carbon steel sheets having 10 mm thickness were subjected to the shielded metal arc welding process with three, five, and seven passes. The variations in the microstructure due to multiple thermal cycles in the heat-affected zone (HAZ), base metal (BM), and fusion zone (FZ) have been investigated and correlated with measured mechanical properties. Upon comparing fracture mechanics and mechanical properties with microstructural observations, it is elucidated that samples become ductile by increasing the number of thermal cycles which can be attributed to the transformations in the ferrite morphology in the HAZ. Based on mechanical, microstructural, and fracture analysis, it is concluded that post-weld heat treatment can be avoided if the number of passes during welding is increased.

Microstructural, mechanical, and electrochemical analysis of carbon doped AISI carbon steels.

The effect of carbon doping contents on the microstructure, hardness, and corrosion properties of heat-treated AISI steel grades of plain carbon steel was investigated in this study. Various microstructures including coarse ferrite-pearlite, fine ferrite-pearlite, martensite, and bainite were developed by different heat treatments i.e. annealing, normalizing, quenching, and austempering, respectively. The developed microstructures, micro-hardness, and corrosion properties were investigated by a light optical microscope, scanning electron microscope, electromechanical (Vickers Hardness tester), and electrochemical (Gamry Potentiostat) equipment, respectively. The highest corrosion rates were observed in bainitic microstructures (2.68-12.12 mpy), whereas the lowest were found in the fine ferritic-pearlitic microstructures (1.57-6.36 mpy). A direct correlation has been observed between carbon concentration and corrosion rate, i.e. carbon content resulted in an increase in corrosion rate (2.37 mpy for AISI 1020 to 9.67 mpy for AISI 1050 in annealed condition).

Biological synthesis, characterization of three metal-based nanoparticles and their anticancer activities against hepatocellular carcinoma HepG2 cells.

Treatment of liver cancer has always been a challenge for clinicians and development of appropriate drug against hepatocellular carcinoma is the major focus for researchers working in the field. The synthesis of metal-based nanoparticles (NPs) by green method for pharmacological uses has attained considerable attention recently. In current study three different NPs (AgO2, CeO2, CuO2) were synthesized by using Trianthima portulacastrum and Chinopodium quinoa leaf extracts. These biogenic NPs were analyzed by High-tech. approaches including Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) spectroscope, SEM-EDS spot analysis, elemental mapping and X-ray diffraction (XRD). The anticancer potential of these nanoparticles was estimated using MTT assay, against hepatic cancer cell line (HepG2). SEM secondary electron images presented the nano size of prepared particles in agglomerated form with few porous forms. Average size of Ag-, Ce-, and CuNPs was observed 19-24 nm, 8-12 nm, 13-15 nm respectively. Elemental mapping and EDS-spot analysis ratifies the formation of AgNPs, CeNPs, and CuNPs. These NPs have shown good anticancer activity at different concentrations against HepG2 cell line. Further studies are however needed to identify the molecular mechanisms of these anticancer activities.

Synthesis and characterization of titanium dioxide nanoparticles by chemical and green methods and their antifungal activities against wheat rust.

The production of metallic nanoparticles (NPs) by green and ecofriendly methods has received consideration during the recent past. The present study summarized the comparative production of titanium dioxide (TiO2) NPs by plant extracts of Trianthema portulacastrum (T2) and Chenopodium quinoa (T3) and by conventional chemical (sol-gel) method (T1). Synthesized TiO2-NPs were examined by high-tech. techniques such as X-Ray Diffraction (XRD), Fourier Transmission Infra-red (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) spectroscope, SEM-EDS spot analysis and elemental mapping. Synthesized TiO2-NPs were applied on wheat rust (Ustilago tritici) for the evaluation of their antifungal activity against toxic plant pathogens. XRD results confirmed the (2θ) peak at 25.3 related to 101 anatase form. EDS-spot analysis and elemental mapping confirms the formation of TiO2-NPs by using these techniques. SEM secondary electrons (SEs) images demonstrated the nano range of particles in cluster form with fewer porous structures. The average size of all three TiO2-NPs was found less than 15 nm. FT-IR analysis of all three TiO2-NPs perfectly matched with the standard parameters. The NPs prepared by both sol-gel and green methods have a good antifungal response against U. tritici, and the green prepared TiO2-NPs were found to have the best antifungal activity against wheat rust especially NPs synthesized with the extract of C. quinoa. Overall, green method can be used for the large scale and less toxic synthesis of TiO2-NPs because of their wide range of environmental applications.