scholarly journals COMPLEX FORMATION BETWEEN HEAVY METALS AND THIOLACETIC ACID IN ELECTRON MICROSCOPIC HISTOCHEMISTRY

1965 ◽  
Vol 13 (7) ◽  
pp. 566-570 ◽  
Author(s):  
NIELS HAUGAARD ◽  
ROBERT S. HORN ◽  
GEORGE B. KOELLE
Keyword(s):  
Heavy Metals ◽  
Complex Formation ◽  
Metal Ions ◽  
Metal Ion ◽  
Bathochromic Shift ◽  
Ultraviolet Spectrum ◽  
Lead Ions ◽  
Electron Microscopic ◽  
Tissue Sections ◽  
Thiolacetic Acid

Evidence for the formations of complexes of aurous and lead ions with thiolacetic acid was obtained by two methods. (1) It was demonstrated that the addition of the metal ions to solutions of thiolacetic acid at pH 6.2 caused a bathochromic shift of the ultraviolet spectrum of this compound characteristic of those observed on combination of metal ions with an organic resonator. The experiments indicated that aurous ions form a coordinate complex with thiolacetic acid containing one metal ion and two thiolacetate residues. (2) It was observed that aurous and lead ions inhibited the reaction of thiolacetic acid with N-ethylmaleimide. Complex formation of the heavy metals with thiolacetic acid may be of importance in preventing their binding at nonspecific sites and in facilitating their penetration into tissue sections in the adaptation for electron microscopy of the thiolacetic acid method for cholinesterases.

scholarly journals Batch Sorption Experiments: Langmuir and Freundlich Isotherm Studies for the Adsorption of Textile Metal Ions onto Teff Straw (Eragrostis tef) Agricultural Waste

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mulu Berhe Desta
Keyword(s):  
Heavy Metals ◽  
Metal Ions ◽  
Contact Time ◽  
Metal Ion ◽  
Low Cost ◽  
Agricultural Waste ◽  
Equilibrium Concentration ◽  
Eragrostis Tef ◽  
Batch Adsorption ◽  
Textile Effluents

Adsorption of heavy metals (Cr, Cd, Pb, Ni, and Cu) onto Activated Teff Straw (ATS) has been studied using batch-adsorption techniques. This study was carried out to examine the adsorption capacity of the low-cost adsorbent ATS for the removal of heavy metals from textile effluents. The influence of contact time, pH, Temperature, and adsorbent dose on the adsorption process was also studied. Results revealed that adsorption rate initially increased rapidly, and the optimal removal efficiency was reached within about 1 hour. Further increase in contact time did not show significant change in equilibrium concentration; that is, the adsorption phase reached equilibrium. The adsorption isotherms could be fitted well by the Langmuir model. The value in the present investigation was less than one, indicating that the adsorption of the metal ion onto ATS is favorable. After treatment with ATS the levels of heavy metals were observed to decrease by 88% (Ni), 82.9% (Cd), 81.5% (Cu), 74.5% (Cr), and 68.9% (Pb). Results indicate that the freely abundant, locally available, low-cost adsorbent, Teff straw can be treated as economically viable for the removal of metal ions from textile effluents.

Adsorption of Cu2+ Metal Ions on Dithizone-Immobilized Natural Bentonite

2020 ◽  
Vol 840 ◽  
pp. 64-70
Author(s):  
Dian Mira Fadela ◽  
Mudasir Mudasir ◽  
Adhitasari Suratman
Keyword(s):  
Adsorption Isotherm ◽  
Complex Formation ◽  
Metal Ions ◽  
Electrostatic Interaction ◽  
Metal Ion ◽  
Synthesis And Characterization ◽  
Optimum Conditions ◽  
Initial Concentration ◽  
Activated Bentonite

The research of adsorption of Cu2+ metal ion on dithizone-immobilized natural bentonite (DNB) had been carried out. The experiment was begun by the activation of natural bentonite with HCl 4 M and dithizone-immobilized on activated bentonite surface. This study included synthesis and characterization of dithizone-immobilized bentonite and its application in adsorption of Cu2+ metal ions. The type of interaction occurred in the adsorption was tested by sequential desorption. The result showed that dithizone successfully immobilized on activated natural bentonite (ANB). The optimum conditions for Cu2+ metal ions adsorption using dithizone-immobilized natural bentonite are at pH 5; 0.1 g mass of adsorbent, with interaction time 60 min, and the initial concentration of ion at 80 ppm. Kinetics and adsorption isotherm studies suggest that the capacity, of the dithizone-immobilized natural bentonite in adsorbing Cu2+ metal ion is significantly improved compared to activated natural bentonite. The adsorption of Cu2+ metal ions by activated natural bentonite was through several interactions dominated by electrostatic interaction (82%). Otherwise, the interaction of dithizone-immobilized natural bentonite with Cu2+ metal ions in the sequence were dominated by the mechanism of complex formation of (75%). The result shows that the immobilization of dithizone changes the type of electrostatic interaction into complex formation.

scholarly journals Plant-Based Tacca leontopetaloides Biopolymer Flocculant (TBPF) Produced High Removal of Heavy Metal Ions at Low Dosage

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 37
Author(s):  
Nurul Shuhada Mohd Makhtar ◽  
Juferi Idris ◽  
Mohibah Musa ◽  
Yoshito Andou ◽  
Ku Halim Ku Hamid ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Metal Removal ◽  
Test Procedure ◽  
Synthetic Wastewater ◽  
Leachate Treatment ◽  
Low Concentration ◽  
Removal Of Heavy Metals

High removal of heavy metals using plant-based bioflocculant under low concentration is required due to its low cost, abundant source, and nontoxicity for improved wastewater management and utilization in the water industry. This paper presents a treatment of synthetic wastewater using plant-based Tacca leontopetaloides biopolymer flocculant (TBPF) without modification on its structural polymer chains. It produced a high removal of heavy metals (Zn, Pb, Ni, and Cd) at a low concentration of TBPF dosage. In our previous report, TBPF was characterized and successfully reduced the turbidity, total suspended solids, and color for leachate treatment; however, its effectiveness for heavy metal removal has not been reported. The removal of these heavy metals was performed using a standard jar test procedure at different pH values of synthetic wastewater and TBPF dosages. The effects of hydroxide ion, pH, initial TBPF concentration, initial metal ion concentration, and TBPF dosage were examined using one factorial at the time (OFAT). The results show that the highest removal for Zn, Pb, Ni, and Cd metal ions were 98.4–98.5%, 79–80%, 97–98%, and 92–93%, respectively, using 120 mg/L dosage from the initial concentration of 10% TBPF at pH 10. The final concentrations for Zn, Pb, Ni, and Cd metal ions were 0.043–0.044, 0.41–0.43, 0.037–0.054, and 0.11–0.13 mg/L, respectively, which are below the Standard B discharge limit set by the Department of Environment (DOE), Malaysia. The results show that TBPF has a high potential for the removal of heavy metals, particularly Zn, Pb, Ni, and Cd, in real wastewater treatment.

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

2022 ◽  
Author(s):  
Zijun Xu ◽  
Yuying Liu ◽  
Jiao Chen ◽  
Xiyuan Wang ◽  
Hao Liu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Heavy Metal Ions ◽  
Sensor Array ◽  
Chelating Agent ◽  
Fluorescence Sensor ◽  
Array Detection ◽  
Multiple Heavy Metals

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.

scholarly journals Adsorption of Cr(VI) Ions using Activated Carbon Produced from Indian Water Chestnut (Trapa natans) Peel Powder

2020 ◽  
Vol 32 (4) ◽  
pp. 876-880
Author(s):  
Maninder Singh ◽  
D. P. Tiwari ◽  
Mamta Bhagat
Keyword(s):  
Heavy Metals ◽  
Metal Ions ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Metal Ion ◽  
Ion Concentration ◽  
Solution Ph ◽  
Indian Water ◽  
Trapa Natans

The indiscriminate discharge of heavy metals into water and soil from anthropogenic practices is becoming prominent threat to the environment. Heavy metals like chromium, cadmium, lead, arsenic, nickel etc. are heavily toxic and carcinogenic in nature. This study emphasizes the adequacy of activated water chest nut (Trapa natans) peel powder as a new adsorbent material for removal of chromium(VI) metal ions. Adsorption experiments were performed in batch process. Various process parameters like contact time, temperature, solution pH, dose of adsorbent, metal ion concentration etc. were optimized. The physico-chemical properties of adsorbent material were characterized by FTIR and XRD. The morphology, topology of adsorbent surface was characterized by scanning electron microscopy (SEM) and Brunauer, Emmett and Teller (BET) which revealed a highly porous structure and available specific surface area. The adsorption capacity (maximum) was counted as 59.17 mg/g and specific surface area was found 23.467 m2/g at a pH 7. The adsorption process for Cr(VI) ions was in a good agreement with Langmuir isotherm. The process also followed pseudo second order kinetics. The obtained result shows that activated water chest nut (Trapa natans) peel powder (AWCPP) can be a hopeful low-cost and eco-friendly bio-adsorbent for removal of Cr(VI) metal ions and also better adsorbent than other various reported adsorbents.

scholarly journals Pelletized ponderosa pine bark for adsorption of toxic heavy metals from water

BioResources ◽  
2007 ◽  
Vol 2 (1) ◽  
pp. 66-81
Author(s):  
Miyoung Oh ◽  
Mandla A. Tshabalala
Keyword(s):  
Heavy Metals ◽  
Metal Ions ◽  
Adsorption Capacity ◽  
Ponderosa Pine ◽  
Metal Ion ◽  
Value Added ◽  
Freundlich Isotherm ◽  
Toxic Heavy Metals ◽  
Adsorption Affinity ◽  
Column Adsorption

ark flour from ponderosa pine (Pinus ponderosa) was consolidated into pellets using citric acid as cross-linking agent. The pellets were evaluated for removal of toxic heavy metals from synthetic aqueous solutions. When soaked in water, pellets did not leach tannins, and they showed high adsorption capacity for Cu(II), Zn(II), Cd(II), and Ni(II) under both equilibrium and dynamic adsorption conditions. The experimental data for Cd(II) and Zn(II) showed a better fit to the Langmuir than to the Freundlich isotherm. The Cu(II) data best fit the Freundlich isotherm, and the Ni(II) data fitted both Freundlich and Langmuir isotherms equally. According to the Freundlich constant KF, adsorption capacity of pelletized bark for the metal ions in aqueous solution, pH 5.1 ± 0.2, followed the order Cd(II) > Cu(II) > Zn(II) >> Ni(II); according to the Langmuir constant b, adsorption affinity followed the order Cd(II) >> Cu(II) ≈ Zn(II) >> Ni(II). Although data from dynamic column adsorption experiments did not show a good fit to the Thomas kinetic adsorption model, estimates of sorption affinity series of the metal ions on pelletized bark derived from this model were not consistent with the series derived from the Langmuir or Freundlich isotherms and followed the order Cu(II) > Zn(II) ≈ Cd(II) > Ni(II). According to the Thomas kinetic model, the theoretical maximum amounts of metal that can be sorbed on the pelletized bark in a column at influent concentration of ≈10 mg/L and flow rate = 5 mL/min were estimated to be 57, 53, 50, and 27 mg/g for copper, zinc, cadmium, and nickel, respectively. This study demonstrated the potential for converting low-cost bark residues to value-added sorbents using starting materials and chemicals derived from renewable resources. These sorbents can be applied in the removal of toxic heavy metals from waste streams with heavy metal ion concentrations of up to 100 mg/L in the case of Cu(II).

scholarly journals Comparative study of binding strengths of heavy metals with humic acid

2013 ◽  
Vol 67 (5) ◽  
pp. 773-779 ◽  
Author(s):  
Ivana Kostic ◽  
Tatjana Andjelkovic ◽  
Ruzica Nikolic ◽  
Tatjana Cvetkovic ◽  
Dusica Pavlovic ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Humic Acid ◽  
Metal Ions ◽  
Stability Constants ◽  
Metal Ion ◽  
Heavy Metal Ions ◽  
Exchange Method ◽  
Divalent Metal Ion ◽  
The Stability

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.

Hydroxyapatite Nanoparticles for Acidic Mine Waters Remediation

2019 ◽  
Vol 70 (9) ◽  
pp. 3167-3175
Author(s):  
Claudia Maria Simonescu ◽  
Daniela Cristina Culita ◽  
Virgil Marinescu ◽  
Christu Tardei ◽  
Dorinel Talpeanu
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Specific Surface ◽  
Metal Ion ◽  
Heavy Metal Ions ◽  
Mining Activities ◽  
Retention Capacity ◽  
Synthesis Conditions ◽  
Mining Wastewater

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.

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