scholarly journals Removal of mercury (II) from aqueous solutions by multiwalled carbon nanotubes coated with manganese oxide

2019 ◽  
Vol 21 (6) ◽  
pp. 258-264
Author(s):  
Abbas Khodabakhshi ◽  
Hassan Asgarian
Keyword(s):  
Heavy Metals ◽  
Carbon Nanotubes ◽  
Aqueous Solutions ◽  
Contact Time ◽  
Structural Characteristics ◽  
Initial Density ◽  
High Concentration ◽  
Nano Composite ◽  
Mn Oxide ◽  
The Impact

Background and aims: Water pollution by heavy metals is one of the most important environmental problems. Among the heavy metals, mercury (Hg) is a very toxic metal and its high concentration can lead to impaired pulmonary and renal dysfunction. The aim of this study was to determine the amount of Hg removal by carbon nanotubes coated with manganese (Mn) oxide from aqueous solutions. Methods: In this study, multi-walled carbon nanotubes coated with Mn oxide were prepared and used to remove Hg from aqueous environments. In addition, the physical and structural characteristics of the nanotubes were determined by the X-ray diffraction (XRD). The impact of diverse variables was further investigated, including the initial concentration of Hg, the initial pH of the solution, contact time, mixing rate, as well as the amount of nano-composite and the impacts of confounders (nitrate and chloride). Finally, optimum conditions for each of these parameters were obtained by the Taguchi statistical method. Results: The XRD analysis showed that the nanotubes were properly coated with Mn oxide. Furthermore, the results demonstrated that under pH 7, the rate of mixing of 150 rpm, the contact time of 60 minutes, the amount of nano-composite of 60 mg, and the initial density of Hg 80 mg/L can be achieved by removing 95% Hg. Moreover, the confounder factors of nitrate and chloride reduced the amount of Hg removal by 4 and 5%, respectively. Conclusion: Based on the results, the nanotubes coated with Mn oxide can be used as easy and strong absorbents for the rapid absorption of Hg from drinking water and industrial wastewater.

scholarly journals Comparative Adsorptive Removal of Selected Heavy Metals from Battery Wastewater by Purified and Polyethylene Glycol Modified Carbon Nanotubes

2021 ◽  
Author(s):  
Abdulkareem AS ◽  
Hamzat WA ◽  
Tijani JO ◽  
Bankole MT ◽  
Titus Egbosiuba ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Carbon Nanotubes ◽  
Polyethylene Glycol ◽  
Toxic Metals ◽  
Contact Time ◽  
Batch Adsorption ◽  
Adsorption Effect ◽  
Adsorbent Dosage ◽  
Modified Carbon Nanotubes ◽  
Nano Adsorbent

Abstract Comparative adsorption study of some toxic metals (Ni, Fe, Cu, Cd, and Pb) from battery industrial effluent by purified and polyethylene glycol-modified carbon nanotubes (CNTs) is reported. The as-prepared CNTs via chemical vapour deposition method (A-CNTs), its acid purified form (P-CNTs), and polyethylene glycol functionalized form (PEG-CNTs) were characterized by HRTEM, BET, HRSEM, FTIR and XRD. The HRSEM and HRTEM micrograph revealed the formation of multi-walled tubular network structures of different inner and outer diameter. The BET study of PEG-CNTs and purified CNTs showed surface areas of 970.81 m2/g and 781.88 m2/g, respectively. The nanomaterials batch adsorption effect of various parameters such as contact time, nano-adsorbent dosage and temperature was conducted. The optimum equilibrium to achieve maximum removal of Cd (83.41 %), Ni (92.79 %), Fe (95.93%), Pb (97.16 %) Cu (99.9 9%) using PEG-CNTs was 90 min of contact time, 0.3 g of nano-adsorbent dosage and 60 oC temperature. While the maximum percentage removal efficiencies accomplished using P-CNTs under the same applied conditions were Cd (78.64 %), Ni (76.12 %), Fe (92.87 %), Pb (90.7 2%) Cu (99.09 %). PEG-CNTs was seen as more effective than P-CNTs. Adsorption data of Ni on P-CNTs followed Langmuir isotherm while the adsorption equilibrium model (Freundlich isotherm) of Ni, Fe, Cu and Pb on PEG-CNTs were fitted well. However, in both cases, the sorption kinetic study followed the pseudo-second-order model. The thermodynamics showed that the removal of toxic metals from battery wastewater was spontaneous and endothermic irrespective of the nano-adsorbents. The study found that surface modification of CNTs by polyethylene glycol adequately improved the nanotubes, thus leading to relatively adsorption capacities of heavy metals from industrial battery effluent.

Modification of Multilayer Carbon Nanotubes for the Removal of Arsenate

2016 ◽  
Vol 16 (4) ◽  
pp. 3835-3840
Author(s):  
Libing Liao ◽  
Gin-Lung Liu ◽  
Jiin-Shuh Jean ◽  
Wei-Teh Jiang ◽  
Zhaohui Li
Keyword(s):  
Carbon Nanotubes ◽  
Contact Time ◽  
Carbon Adsorbent ◽  
Superior Performance ◽  
Solution Ph ◽  
Nano Composite ◽  
X Ray ◽  
Multilayer Carbon Nanotubes ◽  
Removal Of Arsenic ◽  
Composite Carbon

The aim of this study was to explore a new nano-composite carbon adsorbent material for the removal of arsenic from water. The multilayer carbon nanotubes (MCNTs) were treated with different acids and/or modified with iron to create more surface COOH sites or Fe-impregnated MCNTs for the enhanced uptake of As(V). Tests were conducted as a function of initial As(V) concentrations, contact time, and solution pH. The coverage of ferric hydroxides on MCNTs and the uptake of As on Fe-MCNTs were independently confirmed by field emission scanning electron microscope and energy dispersive X-ray spectroscopy analyses. With an As(V) uptake capacities of 27 mg/g on Fe-MCNTs and 14 mg/g on acid-MCNTs, the material showed superior performance for As(V) removal.

scholarly journals Quality Assessment of Akinbo River Sediment around Lafarge Cement Wapco, Ewekoro, Nigeria

2017 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Heavy Metals ◽  
Extraction Procedure ◽  
Aquatic Organisms ◽  
Organic Load ◽  
Sampling Point ◽  
High Concentration ◽  
Chemical Index ◽  
Sediment Ph ◽  
The Impact

A study was conducted to assess the impact of industrial discharge on the quality of sediment obtained from River Akinbo around Lafarge Cement WAPCO, Ewekoro. Four locations were chosen along the water course (River Akinbo) to reflect a consideration of all industrial activities that are capable of changing the quality of sediments. Sediment samples were collected in three monthsbetween (October 2015 - June 2016) at the four sampling points. The physicochemical parameters determined were sediment pH, moisture content, sulphate (mg/l), nitrate (mg/l), phosphate (mg/l) and chloride (mg/L) using standard methods. Sequential Extraction Procedure (SEP) was used to determine the concentration of heavy metals to include (Pb, Cr, Cd, Mn, Ni, Fe) while XRF was used to determine the geo-chemical index of the sediment. Sediment pH is between slightly alkaline, the bioavailability of the metal followed a trend Ni > Cr >Mn> Cd>Pb> Fe with a little interchange at some sampling point. Percentage by weight trend for the XRF were in the order of major metals Al > Fe >Ca> K > Na and in the order of minor metals Mn> Cr > Zn. The concentration of cadmium, chromium and iron were above the permissible limit WHO and FEPA. The high concentration of heavy metals in sediment is most likely as a result of the amount of effluents (dust and waste water) discharged into the river from the factory. To prevent mass extinction of aquatic organisms due to anoxic conditions, proper regulations should be implemented to reduce the organic load the river receives.

scholarly journals Polyaniline Modified with Cobalt-Hexacyanoferrate (PmCH) as an Adsorbent for Removal of Heavy Metals from Aqueous Solutions

2018 ◽  
Vol 51 ◽  
pp. 03004
Author(s):  
Nima Moazezi ◽  
Mohammad Ali Moosavian
Keyword(s):  
Heavy Metals ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Contact Time ◽  
Ion Concentration ◽  
Adsorption Capacities ◽  
Cobalt Hexacyanoferrate ◽  
Optimum Ph ◽  
Removal Of Heavy Metals

In this study, polyaniline modified with cobalt-hexacyanoferrate (PmCH) composite was synthesized and characterized for removal of Rb+, Cd2+, Zn2+, Pb2+, and Ni2+ by FTIR and XRD. The effect of pH, adsorbent dosage, ionic strength, contact time, initial ion concentration, and temperature were studied. The competition adsorption experiments between metal ions were investigated. Batch desorption was also conducted to evaluate the reusability of PmCH. The maximum adsorption capacities were 96.15, 27.17, 17.85, 19.15, and 4.76 mg g-1 of Rb+, Cd2+, Zn2+, Pb2+, and Ni2+, respectively. The optimum pH was determined at natural pH of each solution.

scholarly journals Comparing the Adsorption Performance of Multiwalled Carbon Nanotubes Oxidized by Varying Degrees for Removal of Low Levels of Copper, Nickel and Chromium(VI) from Aqueous Solutions

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 723 ◽  
Author(s):  
Marko Šolić ◽  
Snežana Maletić ◽  
Marijana Kragulj Isakovski ◽  
Jasmina Nikić ◽  
Malcolm Watson ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Carbon Nanotubes ◽  
Aqueous Solutions ◽  
Multiwalled Carbon Nanotubes ◽  
Electrostatic Interactions ◽  
Positive Impact ◽  
Molar Ratio ◽  
Multiwalled Carbon ◽  
Removal Of Heavy Metals ◽  
Low Levels

Functionalized multiwalled carbon nanotubes (MWCNTs) have drawn wide attention in recent years as novel materials for the removal of heavy metals from the aquatic media. This paper investigates the effect that the functionalization (oxidation) process duration time (3 h or 6 h) has on the ability of MWCNTs to treat water contaminated with low levels of Cu(II), Ni(II) and Cr(VI) (initial concentrations 0.5–5 mg L−1) and elucidates the adsorption mechanisms involved. Adsorbent characterization showed that the molar ratio of C and O in these materials was slightly lower for the oxMWCNT6h, due to the higher degree of oxidation, but the specific surface areas and mesopore volumes of these materials were very similar, suggesting that prolonging the functionalization duration had an insignificant effect on the physical characteristics of oxidized multiwalled carbon nanotubes (oxMWCNTs). Increasing the Ph of the solutions from Ph 2 to Ph 8 had a large positive impact on the removal of Cu(II) and Ni(II) by oxMWCNT, but reduced the adsorption of Cr(VI). However, the ionic strength of the solutions had far less pronounced effects. Coupled with the results of fitting the kinetics data to the Elowich and Weber–Morris models, we conclude that adsorption of Cu(II) and Ni(II) is largely driven by electrostatic interactions and surface complexation at the interface of the adsorbate/adsorbent system, whereas the slower adsorption of Cr(VI) on the oxMWCNTs investigated is controlled by an additional chemisorption step where Cr(VI) is reduced to Cr(III). Both oxMWCNT3h and oxMWCNT6h have high adsorption affinities for the heavy metals investigated, with adsorption capacities (expressed by the Freundlich coefficient KF) ranging from 1.24 to 13.2 (mg g−1)/(mg l−1)n, highlighting the great potential such adsorbents have in the removal of heavy metals from aqueous solutions.

scholarly journals Impact of Brewery Waste Sludge on Sorghum (Sorghum bicolor L. Moench) Productivity and Soil Fertility in Harari Regional State, Eastern Ethiopia

2017 ◽  
Vol 5 (4) ◽  
pp. 366 ◽  
Author(s):  
Nano Alemu Daba ◽  
Abduletif Ahmed ◽  
Muktar Mohammed
Keyword(s):  
Heavy Metals ◽  
Soil Fertility ◽  
Block Design ◽  
Mineral Fertilizer ◽  
High Concentration ◽  
Eastern Ethiopia ◽  
Waste Sludge ◽  
Regional State ◽  
The Impact ◽  
Sludge Application

The study was conducted on farmers' field in sofi district of Harari Regional State during 2013/2014 main cropping season, eastern Ethiopia, to investigate the impact of brewery sludge on sorghum production and soil fertility. The treatments comprised seven levels of brewery sludges (0, 2.5, 5.0, 7.5, 10.0, 12.5 and 15.0 t ha-1) and NP inorganic fertilizer at recommended rate, arranged in randomized complete block design with four replications. Application of brewery sludge at 15 t ha-1 significantly increased the yield and biomass yield of sorghum by 79 and 85% over control and by 57 and 67% over NP application, respectively. There was no effect of brewery sludge application on heavy metals concentrations in soil after crop harvest, compared to international standard tolerable level. Co and Se levels were high in the control as well as in the soils treated with brewery sludge indicating the already high concentration of these heavy metals in the soils of the area. Plots, which received higher brewery sludge application, resulted in decreased or less percentage of grain nitrogen content showing the independence of grain protein content on lower brewery sludge level. The nitrogen uptake by sorghum grain, straw and the total was maximum (52.68, 44.25 and 79.03 kg ha-1, respectively) with the application of brewery waste sludge at 10 and 15 t ha-1 which were significantly higher than the other brewery sludge and NP mineral fertilizer applications.

scholarly journals Application of Polyaniline Nano Composite for the Adsorption of Acid Dye from Aqueous Solutions

2012 ◽  
Vol 9 (3) ◽  
pp. 1266-1275 ◽  
Author(s):  
J.Raffiea Baseri ◽  
P.N. Palanisamy ◽  
P. Sivakumar
Keyword(s):  
Aqueous Solutions ◽  
Contact Time ◽  
Langmuir Model ◽  
Batch Adsorption ◽  
Adsorption System ◽  
Acid Dye ◽  
Order Model ◽  
Nano Composite ◽  
Pseudo Second Order ◽  
Acid Violet

In this research, Polyaniline coated sawdust (Polyaniline nano composite) was synthesized via direct chemical polymerization and used as an adsorbent for the removal of acid dye (Acid Violet 49) from aqueous solutions. The effect of some important parameters such as pH, initial concentration of dye, contact time and temperature on the removal efficiency was investigated in batch adsorption system. The adsorption capacity of PAC was high (96.84 %) at a pH of 3-4. The experimental data fitted well for pseudo second order model. Langmuir model is more appropriate to explain the nature of adsorption with high correlation coefficient. The Energy of activation from arrehenius plot suggested that the adsorption of AV49 onto PAC involves physisorption mechanism.

scholarly journals Mining Activities and the Chemical Composition of R. Modonkul, Transbaikalia

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 979
Author(s):  
Zinaida Ivanovna Khazheeva ◽  
Aleksey Maksimovich Plyusnin ◽  
Olga Konstantinovna Smirnova ◽  
Elena Georgievna Peryazeva ◽  
Dashima Ivanovna Zhambalova ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Chemical Composition ◽  
Manganese Oxides ◽  
High Concentration ◽  
Catchment Basin ◽  
Industry Waste ◽  
Major Cations ◽  
Calcium Magnesium ◽  
Physical And Chemical ◽  
The Impact

The Dzhidinsky orefield is located in the Zakamensky district of Buryatia. It is characterized by a high concentration of mineralization in a small area. The ores of the Dzhidinsky economic deposits are complex. This ore field includes Pervomaiskoye Mo, Kholtosonskoe W, and Inkurskoe W deposits. The catchment basin of the river Modonkul is located in the Dzhidinsky orefield. Mineral resource industry waste is a real threat to the city Zakamensk. Currently, the waste of deposits is located at the floodplain terrace and the watershed of the river Modonkul. In this work, the impact of the drainage mine and tributary Inkur on the formation chemical composition of the river Modonkul is studied. The 80 samples of water and suspended matter were taken from a surface of 0–0.5 m on seven sites. Physical and chemical parameters were measured at the sampling sites, and chemical composition was analyzed in the laboratory. In the natural background of the river, the major cations are, in decreasing order, Ca2+ > Mg2+ > Na+ + K+, and major anions are, also in decreasing order, HCO3− > SO42− > Cl−. Along the river, the chemical type of water changes from bicarbonate to sulfate across the sulfate-bicarbonate or bicarbonate-sulfate class and from calcium-magnesium across sodium-calcium-magnesium reverse calcium-magnesium group. Total dissolved solids (TDS) increase by a factor of 4.0–4.7 between the upper and mouth of the river. The dissolved and suspended loads were studied in the mixing zone of acid mine and river water. The different hydrochemistry characteristics may result from Fe, Al, and Mn hydroxide precipitation. The pH values and dissolved oxygen cycles could change the uptake of heavy metals on suspended iron and manganese oxides, and the mechanism of removing it in water. River particulates have the potential of regulating heavy metal inputs to aquatic systems from pollution. The ore elements or the heavy metals are removed from the water in two ways: by the runoff of Modonkul and the sedimentation of suspended material at the bottom. The inflow of mine water into the Modonkul river leads to the rare earth elements (REEs) composition with negative cerium and positive europium anomalies.

Removal of Mercury From Aqueous Solutions by ETS-4 Microporous Titanosilicate: Effect of Contact Time, Titanosilicate Mass and Initial Metal Concentration

2007 ◽  
Author(s):  
C. B. Lopes ◽  
M. Otero ◽  
Z. Lin ◽  
E. Pereira ◽  
C. M. Silva ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Aqueous Solutions ◽  
Contact Time ◽  
Sorption Process ◽  
Exchange Equilibrium ◽  
Toxic Heavy Metals ◽  
Experimental Conditions ◽  
Freundlich Isotherms ◽  
Pseudo Second Order ◽  
Microporous Titanosilicate

Mercury is one of the most toxic heavy metals present in the environment and therefore is extremely important develop new, simple and reliable techniques for its removal from aqueous solutions. A recent line of research within this context is the application of microporous materials. The use of these materials for removing heavy metals from solutions may become a potential clean-up technology in the field of wastewater treatment. In this work it is reported the application of microporous titanosilicate ETS-4 as ion exchanger to remove Hg2+ from aqueous solution. Under batch conditions, we studied the effect of contact time, titanosilicate mass and initial Hg2+ concentration. Only 5 mg of ETS-4 are required to purify 2 litres of water with 50 μg L−1 of metal. Under the experimental conditions, the initial Hg2+ concentration and ETS-4 mass have strong influence on the sorption process, and it is proved that 24 h are almost always sufficient to attain ion exchange equilibrium. Langmuir and Freundlich isotherms were used to fit equilibrium experimental results. The kinetics of mercury removal was reliably described by a pseudo second-order model. On the whole, ETS-4 shows considerable potential to remove Hg2+ from wastewaters.

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