scholarly journals pH-Regulated Carbon Dots Fluorescence Sensor Array Detection of Multiple Heavy Metal Ions Under Stepwise Prediction

Author(s):  
Zijun Xu ◽  
Yuying Liu ◽  
Jiao Chen ◽  
Xiyuan Wang ◽  
Hao Liu ◽  
...  

Abstract As a large amount of heavy metals leaches into water sources from industrial effluents, heavy metal pollution has become an important factor affecting water quality. To enable the detection of multiple heavy metals, we constructed a pH-regulation fluorescence sensor array. Firstly, by adding a metal chelating agent as receptor, metal ions and carbon quantum dots (CDs) were connected to distinguish between Cr6+, Fe3+, Fe2+, and Hg2+ ions. Thus, the lack of affinity between the indicator functional groups and the analyte was solved. Secondly, by adjusting the pH environment of the solution system, an economical and simple array sensing platform is established, which effectively simplified the array construction. In this study, the SX-model was used in the field of fluorescence sensor array detection for metal ion recognition. Based on the strategy of stepwise prediction, combined with the classification and concentration models, the bottleneck of the unified model in previous studies was broken. This sensor array demonstrated sensitive detection of four heavy metal ions within a concentration range from 1 to 50 µM, with an accuracy of 95.45%. Moreover, it displayed the ability to efficiently identify binary mixed samples with an accuracy of 95.45%. Furthermore, metal ions in 15 real samples (lake water) were effectively discriminated with 100% accuracy. A chelating agent was used to improve the sensitivity of heavy metal ion detection and eventually led to high-precision prediction using the SX-model.

2019 ◽  
Vol 11 (1) ◽  
pp. 17-20 ◽  
Author(s):  
Li Li ◽  
Bing Liu ◽  
Zhengbo Chen

In this work, we developed a facile and extensible colorimetric sensor array based on different interactions between methylene blue (MB) and single-stranded DNA (ssDNA) for the discrimination of heavy metal ions.


2013 ◽  
Vol 67 (5) ◽  
pp. 773-779 ◽  
Author(s):  
Ivana Kostic ◽  
Tatjana Andjelkovic ◽  
Ruzica Nikolic ◽  
Tatjana Cvetkovic ◽  
Dusica Pavlovic ◽  
...  

The complexation of humic acid with certain heavy metal ions (Co(II), Ni(II), Cu(II), Zn(II) and Pb(II)) was investigated. The stability constants of humate complexes were determined by method which is based on distribution of metal ions between solution and resin in the presence and the absence of ligand, known as Schubert?s ion exchange method. Experiments were performed at 25 ?C, at pH 4.0 and ionic strength of 0.01 mol dm-3. It was found that the 1:1 complexes were formed between metal ions and humic acid. Obtained results of the stability constants, log ?mn, of complexes formed between the metal ions and humic acid follow the order Co(II) < Ni(II) < Cu(II) > Zn(II) which is the same like in the Irving-Williams series for the binding strength of divalent metal ion complexes. Stability constant of complex between Pb(II) ions and humic acid is greater than stability constants of other investigated metal-humate complexes. The investigation of interaction between heavy metal ions and humics is important for the prediction of the distribution and control of the migration of heavy metals in natural environment.


2019 ◽  
Vol 70 (9) ◽  
pp. 3167-3175
Author(s):  
Claudia Maria Simonescu ◽  
Daniela Cristina Culita ◽  
Virgil Marinescu ◽  
Christu Tardei ◽  
Dorinel Talpeanu

Mining activities have a high negative impact on the environment and on human health. Environmental impacts can result in contamination of surface water, groundwater, soil and air. Large volumes of wastewater produced by mining activities have to be remediated before being discharged into the environment. Due to the complex composition of wastewater coming from the mining industry and because their negative impacts, numerous remediation techniques have been applied. Adsorption is one of the most extensively used ways to remediate mining wastewater as a consequence of its low cost, easiness to be performed, and also due to the wide variety of materials (natural and synthetic) that can be use as adsorbents. Hydroxyapatite (HAP, Ca10(PO4)6(OH)2), a naturally occurring form of calcium phosphate has a good capacity to remove heavy metal ions from aqueous solutions due to its excellent properties. By preparing hydroxyapatite using different synthesis methods, its properties can be manipulated in order to increase the adsorption properties and reactivity. Herein, we reported synthesis of hydroxyapatite (HAP) samples using different synthesis conditions to establish the effect of synthesis conditions onto HAP properties. The HAP samples prepared have been characterized by the use of X-ray diffraction, FT-IR spectroscopy, specific surface measurements, Scanning Electron Microscopy (SEM). The stoichiometric compounds with high degree of crystallinity, low average particle diameter values, and low specific surface have been prepared by the solid state reaction and high calcination temepratures. The addition of surfactant (dispersant) has resulted in an increase in the specific surface area, which will result in an increase in the retention capacity of heavy metal ions in wastewater. The adsorbents prepared were used to remediate mine water. Results showed that non-calcinated HAP samples have a higher heavy metals adsorption capacity compared to HAP samples calcinated at 600 �C and 900 �C. The HAP samples prepared in presence of surfactant exhibit a higher heavy metals adsorption capacity than samples prepared in absence of surfactant. The values of the retention capacity differ depending on the nature of the metal ion: QMn(II) ] QFe(III) ] QZn(II) ] QPb(II) ] QNi(II). A change in the pH of mine water from 2.6 to 5.5 has occur that means that the metal ion retention mechanism goes through chemical reactions. The metal ions retention capacity suggests application of hydroxyapatite for remediation of mining wastewater.


Author(s):  
Gharde A. D. ◽  
Gharde B. D.

This work reports the characterization of intensive industrial and agricultural activity is the basic reason of enormous pollution of the environment. Heavy metals generally occur in water in low concentration as a result of metal industries and partly through geological processes, but these cause direct toxicity both to human and other living beings. Due to their presence obeyed the specified limit. Heavy metals in wastewater has emerged as focus of environment remediation efforts of industrialization, urbanization with new technological advantages. The natural bodies of water are polluted by means of different contaminant like organic refractories, heavy metal ions etc. The significant concentration of some of the heavy metal ions in water are toxic to human being, animals as well as aquatic organisms. Some heavy metal ions even at the trace level has been recognized toxic to the public health. Many metals have been evaluated toxic to aquatic life certain to threshold toxicity level. The effect of tree bark for Cu(II) from copper sulphate on the metal content of industrial wastewater was investigated in the pH of 4-6. It is observed that the method of binding follows the first order adsorption rate expression such as effect of pH, agitation time, doses of bark substrate, initial metal ion concentration, effect of varying temperature were also studied.


2013 ◽  
Vol 726-731 ◽  
pp. 2585-2588
Author(s):  
Xiu Yan Zhou ◽  
Xiang Xin Xue

In this study, the sorption of heavy metals (Cu2+, Pb2+, Zn2+ and Cd2+) from simulated metallurgical wastewater by sepiolite under different dosage, pH, adsorption time and temperature conditions was investigated. The results showed that adsorption increased with the increase of adsorbent dosage until the adsorption equilibrium was reached. When the pH is 6, adsorption of heavy metal ions by sepiolite was in the order of Cu2+ > Zn2+ > Pb2+ > Cd2+ and removal rates of the metal ion were 91%, 90%, 91%, 84%, respectively. The effect of adsorption time on adsorption was not significant. At room temperature, with the adsorption time 45 min, the adsorption of metal ions is almost saturated, adsorption of Cu2+, Pb2+, Cd2+ and Zn2+ was 13.05mg/g, 85.47mg/g, 62.36mg/g and 15.67mg/g, respectively.


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.


2021 ◽  
Vol 904 (1) ◽  
pp. 012009
Author(s):  
A W Abd Byty ◽  
M A Gharbi ◽  
A H Assaf

Abstract Toxic metal pollutants in groundwater should be identified to prevent future health risks. In this paper, the presence of heavy metals in groundwater in the western region of Iraq was investigated. The heavy metals concentrations, including Ni2+, Co2+, Zn2+, Pb2+, Cr3+, Cd2+, As3+ and Hg2+ were explored in twenty selected aquifers near Rutba City and the results were presented as spatial distribution maps. Findings indicate that contamination with the investigated heavy metal ions possesses a serious threat to the study area’s groundwater quality when compared to WHO and IEPA guideline values. Thus, a new approach to remove or adsorb heavy metal ions can be developed for large-scale production and the safe use of these aquifers water. Results revealed that the highest concentrations in mg/L1 of 2.312 in w19, 1.098 in w2, 5.78 in w17, 0.292 in w9, 3.349 in w5, 0.32 in w13, 0.074 in w11 and 5.622 in w1 for Zn2+, Cr3+, As3+, Pb2+, Ni2+, Co2+, Cd2+ and Hg2+ were recorded, respectively.


2021 ◽  
Author(s):  
Rongrong Si ◽  
Daiqi Wang ◽  
Yehong Chen ◽  
Dongmei Yu ◽  
Qijun Ding ◽  
...  

Abstract Heavy metal ion pollutions are of serious threat for our human health, and advanced technologies on removal of heavy metal ions in water or soil are in the focus of intensive research worldwide. Nanocellulose based adsorbents are emerging as an environmentally friendly appealing materials platform for heavy metal ions removal as nanocellulose has higher specific surface area, excellent mechanical properties and good biocompatibility. In this review, we briefly compare the differences of three kinds of nanocellulose and their preparation method. Then we cover the most recent work on nanocellulose based adsorbents for heavy metal ions removal, and present an in-depth discussion of the modification technologies for nanocellulose in assembling high performance heavy ions adsorbent process. By introducing functional groups, such as amino, carboxyl, phenolic hydroxyl, and thiol, the nanocellulose based adsorbents not only remove single heavy metal ions through ion exchange, chelation/complexation/coordination, electrostatic attraction, hydrophobic actions, binding affinity and redox reactions, but also can selectively adsorb multiple heavy ions in water. Finally, some challenges of nanocellulose based adsorbents for heavy metal ions are also prospected. We anticipate that the review supplies some guides for nanocellulose based adsorbents applied in heavy metal ions removal field.


2018 ◽  
Vol 70 ◽  
pp. 11-23 ◽  
Author(s):  
Oleg Marenkov ◽  
Mykola V. Prychepa ◽  
Julia Kovalchuk

In the experiment with marbled crayfishProcambarusvirginalis(Lyko, 2017), chronic effects of various concentrations of heavy metal ions on the physiological state and enzyme activity were investigated. The obtained results showed that among the investigated heavy metals nickel ions influenced the weight indexes and mortality of crustaceans the most negatively. According to the results of the research, significant changes were noted in the individual biochemical parameters of marbled crayfish under the influence of manganese, lead and nickel ions. The most significant changes in the activity of lactate dehydrogenase were detected in muscle tissues affected by manganese and nickel ions. A significant decrease in the activity of succinate dehydrogenase in muscle of marbled crayfish was determined after the action of heavy metal ions. Investigation of changes in the activity of alkaline phosphatase under the influence of the ions of manganese, lead and nickel has its own characteristics, which indicates certain violations in the tissues of cell membranes. Changes in the activity of enzymes were also reflected in the overall protein content. Changes in these parameters may indicate a rapid biochemical response of crustaceans to the toxic effects of heavy metals.


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