scholarly journals Application of electrokinetic in controlling heavy metals migration in sand: A feasibility study

2014 ◽  
Vol 5 (2) ◽  
pp. 8-15
Author(s):  
Cindy Liew ◽  
Leonard L. P. Lim
Keyword(s):  
Heavy Metals ◽  
Environmental Quality ◽  
Human Activities ◽  
Water Velocity ◽  
Operating Conditions ◽  
Carbon Anode ◽  
Initial Concentration ◽  
Electrical Gradient ◽  
Potential Use ◽  
Land Filling

 Uncontrolled migration of heavy metals from human activities in the subsurface can lead to the degradation of environmental quality and potential use of soil and groundwater. This paper studies the feasibility of using electrokinetics in controlling the migration of heavy metals in sand. Copper and iron (initial concentration of 100 mgL-1) are the target heavy metals in this study as they are the most commonly found heavy metals from human activities such as mining and land filling. The performance of electrokinetic in controlling the migration of these heavy metals is tested in a sand tank at combination of water velocity and electrical gradient of 1.3 cm h-1, 0.5 V cm-1 and 0.88 cm h-1, 1 V cm-1, respectively. The formation of gas at electrodes, scouring on carbon anode and corrosion of crocodile clips during experiment (0.88 cm h-1, 1 V cm-1) showed the occurrence of electrokinetics. Further studies need to be conducted to optimize the operating conditions for effective application of electrokinetic in controlling heavy metals migration in sand.

Application of a bio-electrochemical reactor process to direct treatment of metal pickling wastewater containing heavy metals and high strength nitrate

2004 ◽  
Vol 50 (8) ◽  
pp. 111-118 ◽  
Author(s):  
T. Watanabe ◽  
H.W. Jin ◽  
K.J. Cho ◽  
M. Kuroda
Keyword(s):  
Heavy Metals ◽  
Electric Current ◽  
Ph Value ◽  
Electrochemical Reactor ◽  
Hydrogen Gas ◽  
Operating Conditions ◽  
Synthetic Wastewater ◽  
Carbon Anode ◽  
Lead Removal ◽  
Direct Treatment

The fundamental performance of a bio-electrochemical reactor for the direct treatment of metal ickling wastewater was investigated experimentally. In the reactor, carbon anode and cathode were installed. On the cathode, denitrifying microorganisms were immobilized. Continuous experiments were carried out by feeding a synthetic wastewater containing nitrate and binary heavy metal ions, copper and lead, under different operating conditions. Acetate as well as the electric current was supplied at the minimum amount for stoichiometry of the dissimilatory denitrification reaction. The results indicated that the dissolved copper and lead removal, denitrification and neutralization could be achieved simultaneously in a single bio-electrochemical reactor. The dissolved heavy metals were removed by electrochemical deposition on cathode and by the other phenomena such as the formation of insoluble suspensions and the sorption on suspended bacterial sludge. Denitrification proceeded effectively with the utilization of both added acetate and hydrogen gas generated by electrolysis of water. The pH value increased up to around neutral due to the occurrence of denitrification in the reactor, although the influent pH was less than 3. The removal efficiencies of heavy metals and nitrate increased with increasing the current density. The applied electric current was indispensable for sustaining the stable treatment in the reactor.

RESPONSE SURFACE METHODOLOGY FOR OPTIMIZATION OF HEAVY METAL ADSORPTION IN A MULTIMETAL SOLUTION BY BENTONITE-KAOLIN-ZEOLITE PELLETS

2021 ◽  
Vol 17 (37) ◽  
pp. 57-75
Author(s):  
Dalia Elisa CARBONEL-RAMOS ◽  
Hugo David CHIRINOS ◽  
Mery Cecilia GOMÉZ-MARROQUÍN ◽  
Madhu AGARWAL
Keyword(s):  
Heavy Metals ◽  
Metal Ions ◽  
Adsorption Capacity ◽  
Response Surface ◽  
Contact Time ◽  
Operating Conditions ◽  
Order Model ◽  
Initial Concentration ◽  
Clay Pellets ◽  
Adsorbent Dose

Background: Heavy metals contamination of surface and groundwater is a major environmental problem. Clay minerals are porous and are efficient to adsorb metal ions. Amongst the available treatment technologies, adsorption is the most cost-effective, easy to operate, scalable, and replicable to remediate heavy metals from water solution. Aim: This study aimed to assess the adsorption performance of clay pellets of natural aluminosilicates, bentonite (29%), kaolin (4%) and zeolite (67%) to remove heavy metals from aqueous solutions. Methods: The effect of optimal operating conditions like contact time, adsorbent dose, pH, and heavy metals initial concentration has been studied. Kinetic and equilibrium studies were also performed. Adsorbents were characterized using FTIR analysis. Results and Discussion: Optimum values for contact time, adsorbent dose, pH, and initial concentration of lead, copper, and cadmium were; 240 min; 25 g/L; 4.3; and 4mg/L, 7 mg/L and 2 mg/L, respectively. The Langmuir isotherm was the best-fitted isotherm model for the three metals. Adsorption kinetics showed that the lead and copper adsorption followed the pseudo-second-order model while cadmium suited with the pseudo-first-order model. The selectivity of the pellets towards the metal ions was in the order of Pb > Cu > Cd. Conclusions: The new combination of bentonite-kaolinite-zeolite pellets worked well in tertiary wastewater treatment and successfully utilized as a natural adsorbent in multimetal solution. The results confirmed that the used clay pellets have better adsorption capacity than many other reported studies. Maximum adsorption capacity can be further increased by adjusting the calcination temperature and applying chemical treatments to the clay pellets before extrusion. The response surface analysis evaluated the predicted optimal values for the four operating factors.

scholarly journals RESPONSE SURFACE METHODOLOGY FOR OPTIMIZATION OF HEAVY METAL ADSORPTION IN A MULTIMETAL SOLUTION BY BENTONITE-KAOLIN-ZEOLITE PELLETS

2021 ◽  
Vol 18 (37) ◽  
pp. 57-75
Author(s):  
Dalia Elisa CARBONEL-RAMOS ◽  
Hugo David CHIRINOS ◽  
Mery Cecilia GOMÉZ-MARROQUÍN ◽  
Madhu AGARWAL
Keyword(s):  
Heavy Metals ◽  
Metal Ions ◽  
Adsorption Capacity ◽  
Response Surface ◽  
Contact Time ◽  
Operating Conditions ◽  
Order Model ◽  
Initial Concentration ◽  
Clay Pellets ◽  
Adsorbent Dose

Background: Heavy metals contamination of surface and groundwater is a major environmental problem. Clay minerals are porous and are efficient to adsorb metal ions. Amongst the available treatment technologies, adsorption is the most cost-effective, easy to operate, scalable, and replicable to remediate heavy metals from water solution. Aim: This study aimed to assess the adsorption performance of clay pellets of natural aluminosilicates, bentonite (29%), kaolin (4%) and zeolite (67%) to remove heavy metals from aqueous solutions. Methods: The effect of optimal operating conditions like contact time, adsorbent dose, pH, and heavy metals initial concentration has been studied. Kinetic and equilibrium studies were also performed. Adsorbents were characterized using FTIR analysis. Results and Discussion: Optimum values for contact time, adsorbent dose, pH, and initial concentration of lead, copper, and cadmium were; 240 min; 25 g/L; 4.3; and 4mg/L, 7 mg/L and 2 mg/L, respectively. The Langmuir isotherm was the best-fitted isotherm model for the three metals. Adsorption kinetics showed that the lead and copper adsorption followed the pseudo-second-order model while cadmium suited with the pseudo-first-order model. The selectivity of the pellets towards the metal ions was in the order of Pb > Cu > Cd. Conclusions: The new combination of bentonite-kaolinite-zeolite pellets worked well in tertiary wastewater treatment and successfully utilized as a natural adsorbent in multimetal solution. The results confirmed that the used clay pellets have better adsorption capacity than many other reported studies. Maximum adsorption capacity can be further increased by adjusting the calcination temperature and applying chemical treatments to the clay pellets before extrusion. The response surface analysis evaluated the predicted optimal values for the four operating factors.

Comparative Bio-sorption of Cadmium and Nickel Ions from Aqueous Solution onto Fibers of Date Palm using Fluidized Bed Column

2019 ◽  
Vol 70 (5) ◽  
pp. 1507-1512
Author(s):  
Baker M. Abod ◽  
Ramy Mohamed Jebir Al-Alawy ◽  
Firas Hashim Kamar ◽  
Gheorghe Nechifor
Keyword(s):  
Aqueous Solution ◽  
Heavy Metal ◽  
Metal Ions ◽  
Fluidized Bed ◽  
Removal Efficiency ◽  
Heavy Metal Ions ◽  
Date Palm ◽  
Operating Conditions ◽  
Initial Concentration ◽  
Bed Height

The aim of this study is to use the dry fibers of date palm as low-cost biosorbent for the removal of Cd(II), and Ni(II) ions from aqueous solution by fluidized bed column. The effects of many operating conditions such as superficial velocity, static bed height, and initial concentration on the removal efficiency of metal ions were investigated. FTIR analyses clarified that hydroxyl, amine and carboxyl groups could be very effective for bio-sorption of these heavy metal ions. SEM images showed that dry fibers of date palm have a high porosity and that metal ions can be trapped and sorbed into pores. The results show that a bed height of 6 cm, velocity of 1.1Umf and initial concentration for each heavy metal ions of 50 mg/L are most feasible and give high removal efficiency. The fluidized bed reactor was modeled using ideal plug flow and this model was solved numerically by utilizing the MATLAB software for fitting the measured breakthrough results. The breakthrough curves for metal ions gave the order of bio-sorption capacity as follow: Cd(II)]Ni(II).

scholarly journals Levels, Inventory, and Risk Assessment of Heavy Metals in Wetland Ecosystem, Northeast China: Implications for Snow Cover Monitoring

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2161
Author(s):  
Fuxiang Zhang ◽  
Bo Meng ◽  
Shang Gao ◽  
Rupert Hough ◽  
Peng Hu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Snow Cover ◽  
Environmental Quality ◽  
Regional Scale ◽  
Class Ii ◽  
Sanjiang Plain ◽  
Preliminary Evaluation ◽  
Monitoring Method ◽  
The Sanjiang Plain ◽  
Water Pollution Index

Snow cover is a unique environmental medium in cold regions that can cause potential risks to the ecological environment, due to the release of pollutants that are stored in it. In this study, the Qixing River wetland, located in the Sanjiang Plain of China, was taken as the target research area. Heavy metals in snow cover, including Cu, Ni, Cr, Cd, Pb, and Zn were measured at 19 sampling sites. The results showed that the average concentrations of heavy metals were: Zn (103.46 ± 39.16) > Pb (13.08 ± 4.99) > Cr (11.97 ± 2.82) > Ni (9.55 ± 4.96) > Cu (6.19 ± 1.79) > Cd (0.55 ± 0.25) μg·L−1. Cr and Zn were between Class I and Class II in the “Environmental Quality Standards for Surface Water” of China (GB3838-2002). Pb in snow exceeded the upper limit of Class II, and was significantly higher than concentrations measured in water samples from the Qixing River wetland (p < 0.05), indicating that atmospheric deposition during winter was the major source of Pb. The water pollution index (WPI) indicated that 61.0% of samples could be considered of “clean” status, while the contribution of Zn, Pb, and Cr to WPI were 33.3%, 21.0%, and 19.3%, respectively. A preliminary evaluation of heavy metal inventory in snow cover showed that the residue level of Zn was the highest (2313.57 ± 1194.67 μg·m−2), while Cd was the lowest (13.91 ± 10.45 μg·m−2). The areas with high residues of heavy metals were all located near the buffer zone of the wetland (except for Zn), where snow depth tended to be greatest. Exposure analysis indicated that the risks to winter resident birds from snow ingestion was minimal, but it should be noted that the exposure risk was higher in birds with lower bodyweights. This study provides important information and scientific knowledge on the pollution characteristics and residue inventory of heavy metals in wetland ecosystems, while the results can also provide a monitoring method, reflecting atmospheric environmental quality at a local or regional scale.

scholarly journals Copper and Lead Ions Removal by Electrocoagulation: Process Performance and Implications for Energy Consumption

2021 ◽  
Vol 10 (3) ◽  
pp. 415-424
Author(s):  
Aji Prasetyaningrum ◽  
Dessy Ariyanti ◽  
Widayat Widayat ◽  
Bakti Jos
Keyword(s):  
Heavy Metals ◽  
Energy Consumption ◽  
Removal Efficiency ◽  
Current Density ◽  
High Current Density ◽  
Energy Requirement ◽  
Lead Ions ◽  
Initial Concentration ◽  
Electroplating Wastewater ◽  
Electrocoagulation Process

Electroplating wastewater contains high amount of heavy metals that can cause serious problems to humans and the environment. Therefore, it is necessary to remove heavy metals from electroplating wastewater. The aim of this research was to examine the electrocoagulation (EC) process for removing the copper (Cu) and lead (Pb) ions from wastewater using aluminum electrodes. It also analyzes the removal efficiency and energy requirement rate of the EC method for heavy metals removal from wastewater. Regarding this matter, the operational parameters of the EC process were varied, including time (20−40 min), current density (40−80 A/m2), pH (3−11), and initial concentration of heavy metals. The concentration of heavy metals ions was analyzed using the atomic absorption spectroscopy (AAS) method. The results showed that the concentration of lead and copper ions decreased with the increase in EC time. The current density was observed as a notable parameter. High current density has an effect on increasing energy consumption. On the other hand, the performance of the electrocoagulation process decreased at low pH. The higher initial concentration of heavy metals resulted in higher removal efficiency than the lower concentration. The removal efficiency of copper and lead ions was 89.88% and 98.76%, respectively, at 40 min with electrocoagulation treatment of 80 A/m2 current density and pH 9. At this condition, the specific amounts of dissolved electrodes were 0.2201 kg/m3, and the energy consumption was 21.6 kWh/m3. The kinetic study showed that the removal of the ions follows the first-order model.

scholarly journals Determination of metal content and an assessment of the potential use of waste cashew nut ash (CNSA) as a source for potash production

BioResources ◽  
2010 ◽  
Vol 6 (1) ◽  
pp. 529-536
Author(s):  
Mary B. Ogundiran ◽  
Joshua O. Babayemi ◽  
Chima G. Nzeribe
Keyword(s):  
Metal Content ◽  
Dry Matter ◽  
Wood Ash ◽  
Ash Content ◽  
Cashew Nut ◽  
Open Dumping ◽  
Cashew Nut Shell ◽  
Potential Use ◽  
Land Filling

The potential use of waste cashew nut shell (CNS) ash as a source for potash production was investigated in this study. Managing waste ash generated from cashew nut processing is a major challenge, as land filling and open dumping of the waste ashes have been the main options in management of the ash in Nigeria. Economically viable ways of using waste ash rather than having to dispose of it have to be investigated. The CNS was air-dried for 4 weeks and combusted to ashes; the resulting ash was extracted with water for its potash content. Some parameters of the CNS, including moisture, dry matter, and ash content, were determined. Potash yield obtained was 33.4% of 150 g CNS ash used; analysis of the potash gave it a percentage purity of 78%, while purity on recrystalization increased to 86%. Potash yield from CNS ash was comparable to those reported for wood ash, plantain peels, and other agro-wastes. Also, the results showed that the CNS shared similar lignocellulosic properties and characteristics with hardwood biomass.

scholarly journals URBAN ENVIRONMENTAL QUALITY ASSESSMENT BY SHAPE AND SPECTRAL INDICES OF MULBERRY LEAVES

2019 ◽  
Vol 7 (3) ◽  
pp. 184-205
Author(s):  
Snejana Dineva ◽  
Zlatin Zlatev
Keyword(s):  
Quality Assessment ◽  
Environmental Quality ◽  
Principal Components ◽  
Latent Variables ◽  
Support Vector ◽  
Mulberry Leaves ◽  
Environmental Quality Assessment ◽  
Mulberry Leaf ◽  
Vector Machines ◽  
Potential Use

In this paper, an analysis of the potential use of the surface and geometric characteristics of mulberry leaves as parameters for environmental quality assessment is made. Methods have been used to reduce the amount of data of latent variables, linear and kernel variants of principal components. It has been found that a kernel variant of the principal components, combined with nonlinear separating functions of discriminant analysis and a method of support vector machines, are an appropriate methods for distinguishing the degree of air pollution from the mulberry leaf data. The results obtained could be used as preliminary baseline data for future evaluations and studies related to remote monitoring of urban air quality.

scholarly journals Use of Sewage Sludge in Agriculture

2011 ◽  
Vol 68 (2) ◽  
Author(s):  
Daniela CIUPEANU CĂLUGĂRU
Keyword(s):  
Waste Water ◽  
Heavy Metals ◽  
Wastewater Treatment ◽  
Sewage Sludge ◽  
Environmental Protection ◽  
Environmental Quality ◽  
Wastewater Treatment Plants ◽  
Biological Sludge ◽  
The Law ◽  
High Degree

For turning to a high degree of favorability of sludge from wastewater treatment plants, currently the reintroduction in the natural circuit of this waste is an urgent priority. Knowing precisely the composition of chemical and biological sludge from waste water in accordance with the law and the rules of their application, along with modern wastewater treatment appropriate technologies play a key role on environmental protection. Involvement by precise rules, the content of heavy metals in relation to the maximum permitted by law, translate in to particularly advantageous results in terms of environmental quality.

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