scholarly journals Effects of Humic Acid and Natural Sunlight Irradiation on the Behaviour of Zinc Oxide Nanoparticles in the Aqueous Environment

2020 ◽  
Vol 11 (4) ◽  
pp. 11256-11271

The unique properties of ZnO nanoparticles have attracted scientists’ interest to produce on a large-scale. Household items, cosmetics, consumer products, and electric sensors are some products that utilize these ZnO nanomaterials. Eventually, ZnO nanoparticles will be released into the environment in various ways. Once released, ZnO nanoparticles would dissociate into Zn2+ ions, which are toxic to aquatic organisms. The presence of humic acid and exposure to sunlight could affect the dissolution of ZnO nanoparticles. Two sizes of commercial ZnO nanoparticles (< 50 nm and < 100 nm) were chosen to study the influence of humic acid and sunlight on the dissolution. In the presence of humic acid, the dissolution of both sizes is higher, with 67 % and 39 % Zn2+ dissolved for < 50 nm and < 100 nm, respectively. The concentration of Zn2+ ions seems to be consistent or stable when exposed to sunlight. However, the humic acid enhanced the release of Zn2+ ions. Langmuir isotherm model best fitted for the humic acid's sorption onto the ZnO nanoparticles with the process been favorable.

2017 ◽  
Vol 33 (7) ◽  
pp. 564-575 ◽  
Author(s):  
Sohair R Fahmy ◽  
Dawlat A Sayed

More research is needed to understand the interactions of nanoparticles (NPs) with aquatic organisms and their mechanism of toxic action. Zinc oxide nanoparticles (ZnONPs) are the most used engineered metal oxide NPs in consumer products. The present study was designed to evaluate the cytotoxicity, genotoxicity and digestive gland (DG) as well as gill histopathology of the freshwater molluscan bivalve Coelatura aegyptiaca following exposure to ZnONPs (2, 10 and 50 mg/L) for 6 consecutive days. Exposure to ZnONPs (10 and 50 mg/L) induced a significant increase in malondialdehyde, superoxide dismutase and nitric oxide with a concomitant decrease in reduced glutathione, glutathione-S-transferase and catalase levels in the haemolymph, DG and gills of the treated mussels. Following exposure to ZnONPs (50 mg/L), the DG exhibited gradual changes in glandular activity showing hypertrophy and hyperplasia in the glandular cells and irregularity of lamellae and swelling of filaments in the gills. The present investigation revealed that oxidative stress induction, genotoxicity in the haemocytes and histological alterations in the DG and gills of C. aegyptiaca could be the main mechanisms involved in ZnONPs toxicity in aquatic organisms. Thereby, it is suggested that ZnONPs should be applied with more precautions in relevant industries, and occupational health surveillance should be necessarily considered.


RSC Advances ◽  
2016 ◽  
Vol 6 (111) ◽  
pp. 110108-110111 ◽  
Author(s):  
Zhenghui Liu ◽  
Huifang Zhou ◽  
Jiefeng Liu ◽  
Xudong Yin ◽  
Yufeng Mao ◽  
...  

Zinc oxide nanoparticles (ZnO NPs) have been monitored in wastewater treatment plants as their potential adverse effects on functional microorganisms have been causing increasing concern.


RSC Advances ◽  
2015 ◽  
Vol 5 (46) ◽  
pp. 36845-36857 ◽  
Author(s):  
Tingting Ren ◽  
Jie Wang ◽  
Jinfeng Yuan ◽  
Mingwang Pan ◽  
Gang Liu ◽  
...  

P(VC-co-AAEM)/ZnO nanoparticles are prepared by a nano-coating method, and the morphology of the raspberry-like particles is adjusted by hydrophilicity and NaOH concentration.


2020 ◽  
Vol 10 (18) ◽  
pp. 6431
Author(s):  
Byoung-cheun Lee ◽  
Gilsang Hong ◽  
Hyejin Lee ◽  
Pyeongsoon Kim ◽  
Do-Yeon Seo ◽  
...  

Nanomaterials are known to aggregate in the presence of ions. Similarly, the aggregation of zinc oxide nanoparticles (ZnO NPs) exposed to various ions such as sodium chloride and calcium chloride in water systems increases with the ionic strength. Therefore, for accurate toxicity studies, it is necessary to conduct a test using natural organic matters (NOMs) as additional dispersants that strengthen stability with increased repulsive forces. The three types of ecotoxicity tests based on the dispersion stability test using NOM showed that the toxicities of the three test samples decreased in the presence of NOM. To determine how NOM improved dispersion and reduced toxicities, we analyzed the ionization degree of ZnO NPs with and without NOM and found that the solubility was below 2 mg/L with a negligible change over time, implying that the ionization effect was low. The absolute value of the surface charge of particles increased in the presence of NOM, resulting in increased repulsive electrostatic forces and steric hindrance, causing less aggregation and more dispersion. Additionally, although the NOM used in the test is considered an effective dispersant that does not have a toxicological effect on aquatic organisms, the presence of NOM resulted in reduced toxicities and should be further investigated to establish it as a standard test method.


Author(s):  
SUMATHI S ◽  
BANUPRIYA SJS ◽  
AKHILA V ◽  
PADMA PR

Objectives: The aim of the present study is a synthesis of zinc oxide nanoparticles (ZnONPs) by green and chemical method. The nanoparticles were tested for their antimicrobial, antibiofilm activity, biocompatibility, and hemolysis activity. Methods: We have synthesized ZnONPs both by green and chemical synthesis using the coprecipitation method. To understand the functional group, absorbance, crystalline nature, size, and shape of the synthesized particles, Fourier transform infrared (FTIR), ultraviolet–visible spectroscopy, X-ray diffraction, and scanning electron microscopy were done. Antibacterial activity was carried out using different bacterial strains. The cytotoxicity of synthesized nanoparticles was checked using MTT assay with Klebsiella pneumoniae. Antibiofilm activities of both synthesized nanoparticles were done using Staphylococcus aureus and to assess the toxicity of nanoparticles at the cellular level, hemolysis assay was performed. Results: The yield of nanoparticles in green synthesis was much higher when compared to chemical synthesis. Spectral results showed that the synthesized nanoparticles were ZnONPs. Antibacterial, antibiofilm, and hemolysis assay showed that green nanoparticles were more potent than chemical nanoparticles. Conclusion: Hence, green synthesis provides an advantage over chemical synthesis as it is cost effective, environmentally friendly, and easily scaled up for large-scale synthesis.


2020 ◽  
Vol 20 (10) ◽  
pp. 5977-5996 ◽  
Author(s):  
Saee Gharpure ◽  
Balaprasad Ankamwar

With increase in incidence of multidrug resistant pathogens, there is a demand to adapt newer approaches in order to combat these diseases as traditional therapy is insufficient for their treatment. Use of nanotechnology provides a promising alternative as antimicrobial agents as against traditional antibiotics. Metal oxides have been exploited for a long times for their antimicrobial properties. Zinc oxide nanoparticles (ZnO NPs) are preferred over other metal oxide nanoparticles because of their bio-compatible nature and excellent antibacterial potentials. The basic mechanism of bactericidal nature of ZnO nanoparticles includes physical contact between ZnO nanoparticles and the bacterial cell wall, generation of reactive oxygen species (ROS) as well as free radicals and release of Zn2+ ions. This review focuses on different synthesis methods of ZnO nanoparticles, various analytical techniques frequently used for testing antibacterial properties, mechanism explaining antibacterial nature of ZnO nanoparticles as well as different factors affecting the antibacterial properties.


2018 ◽  
Vol 20 (8) ◽  
pp. 5771-5779 ◽  
Author(s):  
Yanmei Sun ◽  
Dianzhong Wen ◽  
Xuduo Bai

Nonvolatile ternary memory devices were fabricated from the composites polymer blends containing zinc oxide (ZnO) nanoparticles.


2018 ◽  
Vol 16 (1) ◽  
pp. 556-570 ◽  
Author(s):  
Khuram Shahzad Ahmad ◽  
Shaan Bibi Jaffri

AbstractHighly stable semiconducting silver doped zinc oxide nanoparticles have been synthesized via facile, biomimetic and sustainable route, through utilization of Zinc acetate dihydrate (C4H6O4Zn · 2H2O) as host, Silver nitrate (AgNO3) as dopant and phytochemicals of angiospermic medicinal plant Prunus cerasifera as the reducing agents. Synthesis of Ag doped ZnO nanoparticles was done in a one pot synthetic mode by varying the amount of dopant from 0.2 – 2.0%. Synthesized photocatalyst nanoparticles were analyzed via UV-vis, FTIR, XRD and SEM. Commendable alleviation in the direct band gap i.e. 2.81 eV was achieved as a result of doping. Silver doped zinc oxide nanoparticles size ranged between 72.11 – 100 nm with rough surface morphology and higher polydispersity degree. The XRD patterns revealed the hexagonal wurtzite geometry of crystals with an average crystallite size of 2.99 nm. Persistent organic dyes Methyl Orange, Safranin O and Rhodamine B were sustainably photodegraded in direct solar irradiance with remarkable degradation percentages up to 81.76, 74.11 and 85.52% in limited time with pseudo first order reaction kinetics (R2 =0.99, 0.99 and 0.97). Furthermore, efficient inhibition against nine microbes of biomedical and agriculturally significance was achieved. Synthesized nanoparticles are potential green remediators of polluted water and perilous pathogens.


2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Meron Girma Demissie ◽  
Fedlu Kedir Sabir ◽  
Gemechu Deressa Edossa ◽  
Bedasa Abdisa Gonfa

The synthesis of metal oxide nanoparticles with the use of medicinal plant extract is a promising alternative to the conventional chemical method. This work aimed to synthesize zinc oxide nanoparticles using a green approach from indigenous “Koseret” Lippia adoensis leaf extract which is an endemic medicinal plant and cultivated in home gardens of different regions of Ethiopia. The biosynthesized zinc oxide nanoparticles were characterized using thermogravimetric analysis, X-ray diffraction, scanning electron microscopy-energy dispersive spectroscopy, transmission electron microscopy, ultraviolet-visible spectroscopy, and Fourier transform infrared spectroscopy. Furthermore, this study also evaluated the antibacterial activity of the synthesized ZnO nanoparticles against clinical and standard strains of Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, and Enterococcus faecalis by the disc diffusion method. According to the result of this study, ZnO nanoparticles synthesized using Lippia adoensis leaf extract showed promising result against both Gram-positive and Gram-negative bacterial strains with a maximum inhibition zone of 14 mm and 12 mm, respectively, using uncalcinated form of the synthesized ZnO nanoparticles.


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