scholarly journals A Multiuse Nanopore Platform with Disposable Paper Analytical Device for the Detection of Heavy Meatal Ions

Author(s):  
Imogen Heaton ◽  
Mark Platt

The pollution of heavy metal ions within the environmental is a global problem. The rapid and precise removal of these contaminants can be aided by identifying and quantifying the composition of the sample. It is therefore crucial to develop effective portable analytical techniques to determine the levels of heavy metal contamination. Paper-based analytical devices (PADs) offer a low cost method making them an excellent platform for onsite environmental sensors. Here we demonstrate how a PAD can be integrated into a multi-use Nanopore platform. The PAD was functionalised with different recognition ligands, who’s surface charge densities varied in the presence of an analyte. The surface of the PAD was placed in contact with a Nanopore which exhibited Ion Current Rectification (ICR). The extent of ICR, was dependent upon the PAD’s surface charge, and the presence of the analyte of interest i.e. the ICR phenomena was exaggerated or diminished indicating the presence of the metal ion in solution. We demonstrate the potential of PAD-ICR using a PAD functionalised with a peptide aptamer specific for nickel ions. Allowing the detection of nickel(II) as low as 0.25 μM even in the presence of other metal ions. After any measurement, the Nanopore surface can be wiped clean, and reused.

2020 ◽  
Author(s):  
Imogen Heaton ◽  
Mark Platt

The pollution of heavy metal ions within the environmental is a global problem. The rapid and precise removal of these contaminants can be aided by identifying and quantifying the composition of the sample. It is therefore crucial to develop effective portable analytical techniques to determine the levels of heavy metal contamination. Paper-based analytical devices (PADs) offer a low cost method making them an excellent platform for onsite environmental sensors. Here we demonstrate how a PAD can be integrated into a multi-use Nanopore platform. The PAD was functionalised with different recognition ligands, who’s surface charge densities varied in the presence of an analyte. The surface of the PAD was placed in contact with a Nanopore which exhibited Ion Current Rectification (ICR). The extent of ICR, was dependent upon the PAD’s surface charge, and the presence of the analyte of interest i.e. the ICR phenomena was exaggerated or diminished indicating the presence of the metal ion in solution. We demonstrate the potential of PAD-ICR using a PAD functionalised with a peptide aptamer specific for nickel ions. Allowing the detection of nickel(II) as low as 0.25 μM even in the presence of other metal ions. After any measurement, the Nanopore surface can be wiped clean, and reused.


2021 ◽  
Vol 12 (2) ◽  
pp. 1884-1898

Natural water gets contaminated with heavy metal ions because of industrial effluents' discharge into the aquatic environment. As these heavy metal ions cause various health hazards, they should be removed from the aqueous solution. Heavy metal ion concentration in the aqueous solution is very less, so conventional metal removal and recovery processes cannot be applied here. The adsorption method is a great alternative to all these processes as it is a cost-effective and easy method. The use of natural, low-cost materials as adsorbents is eco-friendly also. However, metal uptake capacity of low-cost materials is very less. So, modification is required for low-cost materials to increase their efficiency. In the present review, different modification procedures adopted by different researchers have been discussed. Different low-cost materials used are sawdust, fruit and vegetable wastes, soil, minerals, etc. The modifying agents are heat, acids, bases, and other chemicals. Nevertheless, most of the studies are limited to batch tests only. Future research should be carried out on the extension of batch tests to column study for the large-scale treatment of contaminated water, and the cost of modification procedures and their impact on the environment should also be assessed.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Rabia Baby ◽  
Bullo Saifullah ◽  
Mohd Zobir Hussein

AbstractHeavy metal contamination in water causes severe adverse effects on human health. Millions of tons of kernel shell are produced as waste from oil palm plantation every year. In this study, palm oil kernel shell (PKS), an agricultural waste is utilized as effective adsorbent for the removal of heavy metals, namely; Cr6+, Pb2+, Cd2+ and Zn2+ from water. Different parameters of adsorptions; solution pH, adsorbent dosage, metal ions concentration and contact time were optimized. The PKS was found to be effective in the adsorption of heavy metal ions Cr6+, Pb2+, Cd2+ and Zn2+ from water with percentage removal of 98.92%, 99.01%, 84.23% and 83.45%, respectively. The adsorption capacities for Cr6+, Pb2+, Cd2+ and Zn2+ were found to be 49.65 mg/g, 43.12 mg/g, 49.62 mg/g and 41.72 mg/g respectively. Kinetics of adsorption process were determined for each metal ion using different kinetic models like the pseudo-first order, pseudo-second order and parabolic diffusion models. For each metal ion the pseudo-second order model fitted well with correlation coefficient, R2 = 0.999. Different isotherm models, namely Freundlich and Langmuir were applied for the determination of adsorption interaction between metal ions and PKS. Adsorption capacity was also determined for each of the metal ions. PKS was found to be very effective adsorbent for the treatment of heavy metal contaminated water and short time of two hours is required for maximum adsorption. This is a comprehensive study almost all the parameters of adsorptions were studied in detail. This is a cost effective and greener approach to utilize the agricultural waste without any chemical treatment, making it user friendly adsorbent.


2002 ◽  
Vol 20 (9) ◽  
pp. 849-864 ◽  
Author(s):  
Sameer Al-Asheh ◽  
Fawzi Banat ◽  
Dheaya‘ Al-Rousan

Certain industries often produce mixtures of heavy metal ions in their waste products. Because of the nature of heavy metal ions and the adsorption process, such metal ions can compete with each other for the sorption sites on an adsorbent during adsorption processes. In the present work, binary systems composed of copper, zinc and nickel ions were selected as examples of heavy metal ion mixtures and tested via batch adsorption processes using chicken feathers as an adsorbent. The uptake of individual metal ions was depressed by the presence of another. Thus, the uptake of copper ions from an initial copper ion solution of 20 ppm concentration was reduced from 0.042 mmol/g to ca. 0.019 mmol/g by the presence of a similar concentration of nickel ions. The Freundlich, Langmuir and Sips multi-component adsorption models were employed to predict the uptake of metal ions from binary metal ion solutions using constants obtained from adsorption isotherm models applied to single-solute systems.


2019 ◽  
Author(s):  
Chem Int

A study of removal of heavy metal ions from heavy metal contaminated water using agro-waste was carried out with Musa paradisiaca peels as test adsorbent. The study was carried by adding known quantities of lead (II) ions and cadmium (II) ions each and respectively into specific volume of water and adding specific dose of the test adsorbent into the heavy metal ion solution, and the mixture was agitated for a specific period of time and then the concentration of the metal ion remaining in the solution was determined with Perkin Elmer Atomic absorption spectrophotometer model 2380. The effect of contact time, initial adsorbate concentration, adsorbent dose, pH and temperature were considered. From the effect of contact time results equilibrium concentration was established at 60minutes. The percentage removal of these metal ions studied, were all above 90%. Adsorption and percentage removal of Pb2+ and Cd2+ from their aqueous solutions were affected by change in initial metal ion concentration, adsorbent dose pH and temperature. Adsorption isotherm studies confirmed the adsorption of the metal ions on the test adsorbent with good mathematical fits into Langmuir and Freundlich adsorption isotherms. Regression correlation (R2) values of the isotherm plots are all positive (>0.9), which suggests too, that the adsorption fitted into the isotherms considered.


2019 ◽  
Vol 9 (2) ◽  
pp. 151-162
Author(s):  
Shveta Acharya ◽  
Arun Kumar Sharma

Background: The metal ions play a vital role in a large number of widely differing biological processes. Some of these processes are quite specific in their metal ion requirements. In that only certain metal ions, in specific oxidation states, can full fill the necessary catalytic or structural requirement, while other processes are much less specific. Objective: In this paper we report the binding of Mn (II), Ni (II) and Co (II) with albumin are reported employing spectrophotometric and pH metric method. In order to distinguish between ionic and colloidal linking, the binding of metal by using pH metric and viscometric methods and the result are discussed in terms of electrovalent and coordinate bonding. Methods: The binding of Ni+2, Co+2 and Mn+2 ions have been studied with egg protein at different pH values and temperatures by the spectrometric technique. Results: The binding data were found to be pH and temperature dependent. The intrinsic association constants (k) and the number of binding sites (n) were calculated from Scatchard plots and found to be at the maximum at lower pH and at lower temperatures. Therefore, a lower temperature and lower pH offered more sites in the protein molecule for interaction with these metal ions. Statistical effects seem to be more significant at lower Ni+2, Co+2 and Mn+2 ions concentrations, while at higher concentrations electrostatic effects and heterogeneity of sites are more significant. Conclusion: The pH metric as well as viscometric data provided sufficient evidence about the linking of cobalt, nickel and manganese ions with the nitrogen groups of albumin. From the nature and height of curves in the three cases it may be concluded that nickel ions bound strongly while the cobalt ions bound weakly.


Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 685
Author(s):  
Ai-Huei Chiou ◽  
Jun-Luo Wei ◽  
Ssu-Han Chen

A novel surface-enhanced Raman scattering (SERS)-based probe to capture heavy metal ion (Zn2+) by bovine serum albumin (BSA) using Si-nanowire (SiNW) arrays with silver nanoparticles (AgNPs) was developed. A layer with AgNPs was deposited on the SiNW surface by RF magnetron sputtering for enhancement of SERS signals. Using a high-resolution transmission electron microscope (HRTEM), the observation reveals that the AgNP layer with depths of 30–75 nm was successfully deposited on SiNW arrays. The Ag peaks in EDS and XRD spectra of SiNW arrays confirmed the presence of Ag particles on SiNW arrays. The WCA observations showed a high affinity of the Ag–SiNW arrays immobilized with BSA (water contact angle (WCA) = 87.1°) and ZnSO4 (WCA = 8.8°). The results of FTIR analysis illustrate that the conjugate bonds exist between zinc sulfate (ZnSO4) and –OH groups/–NH groups of BSA. The resulting SiNWs/Ag NPs composite interfaces showed large Raman scattering enhancement for the capture of heavy metal ions by BSA with a detection of 0.1 μM. BSA and ZnSO4 conjugations, illustrating specific SERS spectra with high sensitivity, which suggests great promise in developing label-free biosensors.


2012 ◽  
Vol 12 (2/3/4) ◽  
pp. 318 ◽  
Author(s):  
Ali Ahmadpour ◽  
Tahereh Rohani Bastami ◽  
Masumeh Tahmasbi ◽  
Mohammad Zabihi

2014 ◽  
Vol 625 ◽  
pp. 889-892 ◽  
Author(s):  
Safoura Daneshfozoun ◽  
Bawadi Abdullah ◽  
Mohd Azmuddin Abdullah

This study developed an effective and economical physical pretreatment of OPEFB to be used as biosorbent for the removal of heavy metal ions such as Cu+2, Zn+2and Pb2+. The effects of fibres sizes, metal ions concentration (100-1000 ppm), initial pH (4-10) and contact time (20-150 min) were investigated in batch system. Samples were characterized with Atomic Absorption Spectrometry (AAS), Transmission Electron Microscopy (TEM) and Fourier Transmission Infra-red Spectroscopy (FTIR). Results showed pH-dependence adsorption efficiency and increased adsorption with initial metal concentrations where more than 92% adsorption efficiency achieved. We have successfully developed an eco-friendly, low cost adsorbent without any chemical modification or excessive energy disposal.


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