E-waste management, treatment options and the impact of heavy metal extraction from e-waste on human health: Scenario in Vietnam and other countries.

Ho Chi Minh (HCM) City is the most important urban region of Vietnam, Southeast Asia. In recent times, the quantity of electronic waste (e-waste) has been growing by several thousand tonnes every year. In this research, some of the existing and developing technologies being employed for the recycling of e-waste have been reviewed. Accordingly, the paper has been divided into three sections namely, e-waste treatment technologies in Ho Chi Minh City, the effect of heavy metals on human health and the extraction of metals from e-waste using pyrolysis, hydrometallurgy, bioleaching, mechanical, and air classifier methods, respectively. The extraction of precious metals and heavy metals such as Cd, Cr, Pb, Hg, Cu, Se, and Zn from e-waste can be hazardous to human health. For example, lead causes hazards to the central and peripheral nervous systems, blood system and kidneys; copper causes liver damage; chronic exposure to cadmium ends up causing lung cancer and kidney damage, and mercury can cause brain damage. Thus, this study examines the key findings of many research and review articles published in the field of e-waste management and the health impacts of metal pollution.

Anti-diabetic efficacy and selective inhibition of methyl glyoxal, intervention with biogenic Zinc oxide nanoparticle.

Non-enzymatic glycation of biomolecules results in advanced glycation end products (AGEs), which are responsible for secondary complications in diabetes. Inhibiting methyl glyoxal (MGO) induced advanced glycation end product (AGE) formation is the only way to alleviate diabetic complications. This study aimed to look into the abilities of herbal extract Kigelia africana and K. africana synthesized zinc oxide nanoparticles (ZnONPs) to inhibit the emergence of MG-derived AGEs. The study intended to determine antioxidant and AGE inhibition of the plant extract and ZnONPs. ZnONPs were tested for the efficiency of anti-diabetic activity in streptozotocin-induced diabetic Wister rats. We discovered that the MGO-trapping effects on the prevention of AGE production were mediated by the downregulation of the amplification of MGO-trapping impacts on the hypoglycemic and antihyperlipidemic mechanisms of ZnONPs. According to histological findings, the treatment with ZnONPs also successfully lowers inflammation in the hepatic and renal tissues. Overall, future mechanistic research could establish ZnONPs potential anti-diabetic properties.

Evaluation of cadmium tolerance and remediated efficacy of wild and mutated Enterobacter species isolated from potassium nitrate (KNO3) processing unit contaminated soil.

The purpose of this study was to find the most cadmium (Cd2+) tolerant and remediated bacteria isolate from KNO3 processing unit contaminated soil. One isolate out of 19 isolates possessed excellent Cd2+ tolerance than others, which was recognized as Enterobacter hormaechei SFC3 through molecular characterization (16S rRNA sequencing). The identified E. hormaechei SFC3 contained 55% and 45% of GC and AT content, respectively. The wild and acridine orange mutated E. hormaechei SFC3 exhibited excellent resistance to Cd2+ up to the concentration of 1500 µg mL-1. Furthermore, the wild E. hormaechei SFC3 and mutated E. hormaechei SFC3 showed 82.47% and 90.21% of Cd2+ remediation on 6th days of treatment respectively. Similarly, the Cd2+ tolerant wild and mutated E. hormaechei SFC3 showed considerable resistance to all the tested antibiotics. The findings indicate that E. hormaechei SFC3 isolated from KNO3 processing unit contaminated soil is a promising candidate for microbial remediation of Cd2+ contamination.

Green synthesis of copper oxide nanoparticles using Abutilon indicum leaves extract and their evaluation of antibacterial, anticancer in human A549 lung and MDA-MB-231 breast cancer cells.

In currently, biosynthesis of copper oxide nanoparticles (CuO NPs) are most widely used numerous in biological applications such as biosensor, energy, medicine, agriculture, environmental and industrial wastewater treatment. The hierarchical CuO NPs was synthesized via green chemistry method by using of Abutilon indicum (A. indicum) leaf extract, its nontoxic, facile and low-cost approaches. Biogenic synthesized CuO NPs was characterized by using a UV-visible absorption spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Field mission scanning electron microscopy (FE-SEM) with Energy-dispersive X-ray spectroscopy (EDX) analysis. The synthesized CuO NPs was performed antibacterial activity against human pathogenic organisms of both Gram negative (Escherichia coli and Salmonella typhi) and Gram positive (Bacillus subtilis and Staphylococcus aureus) bacteria by using agar well diffusion method. Biological synthesized CuO NPs was showed potential bactericidal activity against Gram positive bacteria of B. subtilis than compared to Gram negative bacteria of E. coli. The cytotoxic effect of A. indicum mediated synthesized CuO NPs was evaluated against to human lung A549 and breast MDA-MB-231cancer cell lines by determined using of MTT assay. In furthermore, photocatalytic dye degradation was performed that synthesized CuO NPs have effectively removed 78% of malachite green dye molecule. Our investigation results suggested that the green synthesized CuO NPs potential biological activity of antibacterial activity against Gram positive bacterial, anticancer activity was effectively against MDA-MB-231cancer cell line and good dye degradation was exhibited in malachite green. The A. indicum aqueous leaf extract mediated synthesized CuO NPs has strongly suggested promising nano-biomaterials for fabrication of biomedical applications.

Synthesis of hydroxyapatite nanoparticles using Acacia falcata leaf extract and study of their anti-cancerous activity against cancerous mammalian cell lines.

This study deals with the synthesis of hydroxyapatite nanoparticles (HAPnps) mediated by Acacia falcata leaf extract. Aggregates of needle-shaped crystalline nanostructures were confirmed by FE-SEM and TEM analysis. Well-defined rings in the SAED patterns corroborated the polycrystalline nature of the HAPnps. Individual elements present in the HAPnps were attested by the specific signals for Ca, P, and O in the EDS and XPS analyses. The distinct peaks observed in the XRD spectrum matched well with the HAP hexagonal patterns with a mean crystallite size of 55.04 nm. The FTIR study unveiled the coating of the nanoparticles with the biomolecules from Acacia falcata leaves. The suspension HAPnps exhibited polydispersity (0.446) and remarkable stability (zeta potential: - 31.9 mV) as evident from DLS studies. The pore diameter was 25.7 nm as obtained from BET analysis, suggesting their mesoporous nature. The HAPnps showed the cytotoxic effect on A549 lung and MDA-MB231 breast carcinoma cell lines, with an IC50 value of 55 µg/mL. The distortion of the cell membrane and cell morphology, along with the chromatin condensation and cell necrosis on treatment with HAPnps were detected under fluorescence microscopy post acridine orange/ethidium bromide dye staining. This study reports the anti-cancerous potential of non-drug-loaded plant-mediated HAPnps. Therefore, the HAPnps obtained in this investigation could play a vital role in the biomedical field of cancer therapy.

Synthesis, characterization and anticancer activity of the green-synthesized hematite nanoparticles.

The conventional synthesis of hematite nanoparticles (HNPs) is expensive and creates secondary contaminants. Therefore, to combat these issues, there is a requirement for a cheap, effective, and eco-friendly technique. Herein, HNPs were prepared using the fruit extract of Spondias pinnata - an abundant source available in Western-coastal India. The polyphenolic compounds aided the synthesis process and the entire procedure was very rapid. The obtained HNPs had needle-like morphology with agglomerations due to the magnetic interactions as seen in FESEM and HRTEM images. Fe and O elements were noticed in EDS results. The crystalline nature and crystal phase were confirmed from XRD and SAED patterns. The lattice parameters of HNPs were in tandem with the literature. Fe-O crystalline vibrations were noticed in FTIR studies. VSM results portrayed the superparamagnetic nature of HNPs with a high magnetic saturation value of 8.949 emu/g and a negligible hysteresis loop. Thermal stability was ascertained using TGA results with 32% overall weight loss. XPS studies revealed the existence of pure HNPs with signature peaks. Raman spectrum showed the bands specific for HNPs, comparable to the commercial one. In addition, the HNPs were mesoporous with a high surface area (72.04 m2/g) - higher than the commercial one. The anticancer potential of the HNPs was successfully demonstrated against two mammalian cancer cell lines. Therefore, the HNPs synthesized in this study could be applied in various biomedical fields, especially for anticancer formulations.

Fungi fabrication, characterization, and anticancer activity of silver nanoparticles using metals resistant Aspergillus niger.

The purpose of this study was to assess the bio-fabrication possibilities of pre-isolated (from bauxite mine tailings) metal-tolerant Aspergillus niger biomass filtrate and the anticancer potential of synthesized silver nanoparticles (AgNPs) tested with a Human Cervical cancer cell line (HeLa cells: Henrietta Lacks cells). The nitrate reduction test demonstrated that A. niger has the ability to reduce nitrate, and filtrate derived from A. niger biomass efficiently fabricated AgNPs from AgNO3, as demonstrated by a visible color change from pale greenish to brownish. The UV-visible spectroscopy analysis revealed an absorbance peak at 435 nm, which corresponded to the AgNPs. These AgNPs have been capped and stabilized with several functional groups related to various bioactive molecules such as aldehyde, benzene rings, aldehydic, amines, alcohols, and carbonyl stretch protein molecules. Fourier-Transform Infrared Spectroscopy (FTIR) analysis confirmed the capping and stabilizing chemical bonding pattern. Scanning Electron Microscopy (SEM) revealed that the synthesized AgNPs were spherical, with an average size of 21.38 nm. This bio-fabricated AgNPs has in-vitro anticancer potential when tested against the HeLa cell line due to its potential size and shape. At 100 g mL-1 concentrations of this bio-fabricated AgNPs, the anticancer activity percentage was found to be 70.2%, and the IC50 value was found to be 66.32 g m-1. These findings demonstrated that the metal-tolerant A. niger cell filtrate could produce AgNPs with anticancer potential.

Microwave assisted biodiesel production from chicken feather meal oil using Bio-Nano Calcium oxide derived from chicken egg shell.

Environmental concerns have initiated the search for greener measures to mitigate pollution issues. Bio Nano CaO was synthesized by reducing CaO extracted from chicken egg shell using tea decoction. The synthesized material was characterized by physico-chemical techniques such as XRD, TGA, BET surface area analyser, TGA and SEM techniques. XRD studied confirmed the crystalline nature of material. The prepared material was found to be stable till 450 οC from TGA study. The SEM pictures displayed uniform and discrete particles which portrays the high probable sites that maximises the catalytic activity. The optimization of microwave assisted Biodiesel synthesis from chicken feather oil through Transesterification process using the bio-synthesized catalytic material was the main aim of the study. A 500 W microwave irradiation of Chicken feather meal oil using 8:1 Methanol:Oil input, 1% Bio Nano CaO concentration, 5 min of reaction time resulted in 95% conversion of chicken feather meal oil into chicken feather meal methyl esters. The Biodiesel was showed low viscosity (4.15 mm2/s), high heating value (50 MJ/kg), high flash point (153οC), reasonable pour point (12 οC) and good cetane number (50 min). The future works will be concentrated on the engine studies related to Torque, fuel consumption, emission data by using the synthesized Biodiesel.