scholarly journals Efficiency of biochars in the removal of heavy metals

2019 ◽  
Vol 3 (3) ◽  
pp. 131 ◽  
Author(s):  
Denise Domingos dos santos Martins ◽  
Juan Carlos Valdés Serra ◽  
Joel Carlos Zukowski Junior ◽  
Marcelo Mendes Pedroza
Keyword(s):  
Heavy Metals ◽  
Effective Treatment ◽  
Membrane Separation ◽  
Chemical Precipitation ◽  
Production Costs ◽  
High Rate ◽  
Oxidation Reduction ◽  
Removal Of Heavy Metals ◽  
Exchange Membrane ◽  
Copper Lead

Toxic metals are naturally present in the environment even if there is no anthropic action. Several methods are used for the removal of these metals from water and effluents, such as: chemical precipitation, oxidation/reduction, filtration, ion exchange, membrane separation, and adsorption. Biosorption stands out as an effective treatment because it has a high rate of renewal in nature, low production costs, and high removal of metals due to the possibility of recovery of the contaminant, either by incinerating the biomass or by desorbing it. Thus, this study identified some biochars used as adsorbents for the removal of  copper, lead, chromium, and mercury in water. It can be concluded from this study that adsorption is a very efficient technique for removing or recovering heavy metals from the environment. These biocarbons are alternatives that can replace commercial activated carbon because, besides having a low production cost, they have been shown to efficiently remove metal ions, ensuring an effective treatment in compliance with effluent release standards.

scholarly journals Removal of Heavy Metal from Wastewater using Water Chestnut Shell as an Adsorbent

2021 ◽  
Vol 9 (VI) ◽  
pp. 3113-3120
Author(s):  
Girish R. Jangle
Keyword(s):  
Heavy Metals ◽  
Membrane Separation ◽  
Activated Carbons ◽  
Low Cost ◽  
Chemical Activation ◽  
Cost Effective ◽  
Chemical Precipitation ◽  
Chemical Oxidation ◽  
Cost Effective Approach ◽  
Exchange Membrane

The contamination of water resources as a result of industrial activity is on the rise and is a global concern. The heavy metals found in wastewater are long lasting and non-biodegradable. Contamination with heavy metals over acceptable limits could result in major health problems. Chemical precipitation, chemical oxidation, ion exchange, membrane separation, reverse osmosis, electrodialysis, adsorption, and other technologies are used to lessen the influence of heavy metals on water bodies. Some procedures are extremely costly, energy-intensive, and frequently result in the production of harmful by-products. The use of adsorption as a cost-effective approach for removing heavy metals from industrial wastewater has been examined. The usage of Trapa bispinosa peels/shell as a low-cost adsorbent for wastewater treatment is discussed in this paper. Chemical activation was used to make activated carbons from Trapa bispinosa peels and shells. Activated carbons made from a combination of Trapa bispinosa peels/shells and Phosphoric acid with varying impregnation ratios. The results revealed that the activating temperature for the production of Trapa bispinosa-derived activated carbon is 500℃ (AC). CHNS, X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy were used to analyze the activated carbons.

scholarly journals Removal of Heavy Metal (Chromium) From Aqueous Solution using Acacia Arabica Wood (Black Babul)

2019 ◽  
Vol 8 (4) ◽  
pp. 1495-1498
Keyword(s):  
Heavy Metals ◽  
Aqueous Solution ◽  
Membrane Separation ◽  
Chemical Precipitation ◽  
Polluted Water ◽  
Process Time ◽  
Human Beings ◽  
Waste Products ◽  
Ultra Filtration ◽  
Exchange Membrane

Heavy metals become a serious problem to society in the view of water pollution. Polluted water causes many disorders in human beings, animals and plants also. The concentration of heavy metals increases mainly due to the activities like mining, agricultural activities and disposal of industrial waste products. Most of the activities releases heavy metals like Mercury (Hg), chromium(Cr), arsenic(Ar), thallium (Tl), nickel (Ni), lead (Pb), and cadmium (Cd). Separation of these heavy metals from water many treatment methods are available like chemical precipitation, ion exchange, membrane separation, electrodialysis, ultra-filtration, nano filtration, coagulation, flocculation, floatation and adsorption. Adsorption is the best method out of all these methods. Activate carbon is normally used as adsorbent but it is expensive. Black babul wood is the cheapest and abundant available in nature. So treatment of heavy metals black babul wood used as adsorbent. In this article, effect of parameters like process time, initial concentration, adsorbent dosage, adsorbent particle and temperature on separation of Chromium from aqueous solution is studied.

Derivation of Optimum Study Factors for Samples Contaminated with Cd Using Electric/Magnetic Field and ORP

2013 ◽  
Vol 813 ◽  
pp. 519-524
Author(s):  
Sang An Ha ◽  
Jei Pil Wang
Keyword(s):  
Magnetic Field ◽  
Heavy Metals ◽  
Removal Rate ◽  
Underground Water ◽  
Liquid Electrode ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Removal Of Heavy Metals ◽  
High Removal Rate ◽  
Membrane Treatment

A purpose of the present study is to derive optimum study factors for removal of heavy metals using combined alternating current electric/magnetic field and electric membranes for the area contaminated with heavy metals in soil or underground water. ORP (Oxidation Reduction Potential) analysis was conducted to determine an intensity of tendency for oxidation or reduction of the samples contaminated with heavy metals, and electrical membrane treatment was used with adjustment of concentrations and voltages of liquid electrode (Na2SO4) to derive a high removal rate. Removal constants were analyzed to be 0.0417, 0.119, 0.1594 when the voltages were 5V, 10V, 15V, respectively, and treatment efficiency was shown to increase as the liquid electrode concentration was increased. Keywords: heavy metals, electric/magnetic field, ORP, electrical membrane

Enhanced Electrokinetic Removal of Heavy Metals in MSWI Fly Ash Assisted by Cation Exchange Membranes

2011 ◽  
Vol 84-85 ◽  
pp. 626-630 ◽  
Author(s):  
Xi Peng ◽  
Bin Quan Jiao ◽  
Lin Yu ◽  
Dong Wei Li ◽  
Ke Yang
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Cation Exchange ◽  
Electroosmotic Flow ◽  
Metal Extraction ◽  
Mswi Fly Ash ◽  
Assisted Extraction ◽  
Removal Of Heavy Metals ◽  
Trial Test ◽  
Exchange Membrane

Since MSWI fly ash enriches heavy metals and many toxic components and these components would potentially leach when the ashes are land filled, it is regulated as hazardous waste in many countries. Electrokinetic removal, an electrochemically assisted extraction method, has recently been adopted as a new method for removal of heavy metals from MSWI fly ashes. But the generation of metal hydroxide precipitation near the cathode decreased conductivity of electrokinetic removal system and limited metal extraction from the sample area. In this study, cation exchange membrane was used in electrokinetic removal experiment to improve this method. After 192 hours of electrokinetic removal, about 15%Cd,20%Pb, 30% Zn, and 10% As was removed from 2.850kg MSWI fly ash. It showed positive effect compared to the trial test. But there still exists some problems, such as low removal efficiency. Further work should be done to solve it.Moreover, the high conductivity in fly ash limits the current , which in turn causes low electroosmotic flow. While electroosmotic flow is the main factor leting the heavy meatals release from fly ash, it would become the focus in further experiment to look for ways increasing the electroosmotic flow in sample cell.

scholarly journals Magnetic Graphene Oxide Composites are the Solutions for Sustainable Remediation of Ecosystems

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Lakshmi Prasanna Koduru
Keyword(s):  
Heavy Metals ◽  
Graphene Oxide ◽  
Membrane Separation ◽  
Anthropogenic Activities ◽  
Low Cost ◽  
Cost Effective ◽  
Hybrid Nanocomposites ◽  
Magnetic Graphene Oxide ◽  
Removal Of Heavy Metals ◽  
Potential Applications

Heavy metals are one of the primary contaminants in the environment [1]. Exposure to heavy metals, even at trace levels, is believed to be a high health risk for humans [2,3]. Heavy metals are naturally occurring throughout the earth’s crust [4]. But most of the environmental contamination results from the anthropogenic activities such as mining and smelting operations, industry, and domestic and agricultural use of metals and metalcontaining compounds. Migration of these contaminants into non-contaminated areas as dust or leachates through the soil and spreading of heavy metals containing sewage sludge are a few examples of events contributing towards contamination of the ecosystems [5]. Hence, water is the one of the major routes through which heavy metals and radionuclides may enter the human body [6,7]. The sources of water pollution are shown in Figure 1. The conventional wastewater purification techniques including chemical coagulation, photo degradation, precipitation, flocculation, activated sludge, membrane separation and ion exchange are limited to the removal of heavy metals at trace levels [7-9]. However, adsorption is one of the best methods for the purification of water, owing to its low cost and easy handling of materials [7,10-12]. Moreover, adsorption approaches using commercial activated carbon, micro-filtration and membrane techniques are effective, but their use is limited by the complicated installation process involved coupled with the high maintenance costs of the systems [7,13]. Hence, these drawbacks have necessitated the search for an alternative method which is inexpensive, renewable and cost-effective for the removal of heavy metals from aqueous solutions. Many scientific groups have prepared graphene or graphene oxide (GO) based hybrid nanocomposites for various potential applications [14-17]. The study of literature survey and stability of the GO-based nanocomposites prompted us to survey on graphene oxide and reduced graphene oxide-based inverse spinel nickel ferrite nanocomposites for the removal of heavy metals and radionuclides from water with the purpose of reducing their environmental impact

Continuous removal of heavy metals from FGD wastewater in a fluidised bed without sludge generation

1997 ◽  
Vol 36 (2-3) ◽  
pp. 391-397 ◽  
Author(s):  
P. B. Nielsen ◽  
T. C. Christensen ◽  
M. Vendrup
Keyword(s):  
Heavy Metals ◽  
Flue Gas ◽  
Waste Product ◽  
Chemical Precipitation ◽  
Fluidised Bed ◽  
Power Station ◽  
Treatment Processes ◽  
Fluid Bed ◽  
Removal Of Heavy Metals ◽  
Dissolved Heavy Metals

A patent pending fluid-bed process has been developed by Krüger for removal of dissolved heavy metals by adsorption/coprecipitation. The waste product is a very compact granulate with a very low water content of 10-20%. Sludge is not produced. The fluid-bed technique was tested at a coal-fired power station with wastewater from the flue gas desulphurisation (FGD) unit for removal of heavy metals from the wastewater. By dosing only potassium permanganate to the wastewater, the content of dissolved nickel, cadmium and zinc was reduced by respectively 99%, 92% and 97% at optimum treatment in one fluid-bed reactor. The weight of waste product produced will constitute less than 25% of the waste product produced by the present traditional chemical precipitation. Chemical costs are approximately 0.6 US$/m3 which are similar for the fluid-bed and present wastewater treatment processes.

scholarly journals Magnetic Hydroxyapatite for Batch Adsorption of Heavy Metals

2021 ◽  
Vol 287 ◽  
pp. 04005
Author(s):  
Khee Chung Hui ◽  
Norashikin Ahmad Kamal ◽  
Nonni Soraya Sambudi ◽  
Muhammad Roil Bilad
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Removal ◽  
Aqueous Media ◽  
Heavy Metal Removal ◽  
Calcium Nitrate ◽  
Chemical Precipitation ◽  
Batch Adsorption ◽  
Calcium Nitrate Tetrahydrate ◽  
Removal Of Heavy Metals

In this work, magnetic hydroxyapatite or hydroxyapatite-iron (III) oxide (HAp-Fe3O4) composite was used as the adsorbent of heavy metals and the performance was evaluated using the batch test. The presence of heavy metals in the effluent from wastewater discharge can be toxic to many organisms and can even lead to eye burns. Therefore, hydroxyapatite synthesized from the chemical precipitation of calcium nitrate tetrahydrate and diammonium hydrogen phosphate solutions is used to remove heavy metal in aqueous media. Magnetic properties of Fe3O4 can help prevent formation of secondary pollutants caused by the loss of adsorbent. The synthesized HAp-Fe3O4 can remove cadmium, zinc and lead effectively, which is up to 90% removal. Reusability study shows that the adsorbent could retain heavy metal ions even after four cycles. The percentage removal of heavy metals maintains at around 80% after four times of usage. The composite of HAp-Fe3O4 demonstrates good performance and stability which is beneficial for heavy metal removal in the future.

Selection and test of effective chelators for removal of heavy metals from contaminated soils

1995 ◽  
Vol 22 (6) ◽  
pp. 1185-1197 ◽  
Author(s):  
Ting-Chien Chen ◽  
Edward Macauley ◽  
Andrew Hong
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Contaminated Soils ◽  
Chelating Agents ◽  
Heavy Metal Contamination ◽  
Recovery Potential ◽  
Wide Range ◽  
Removal Of Heavy Metals ◽  
Zinc Chelator ◽  
Copper Lead

Heavy metal contamination of soil is a common problem at many hazardous waste sites. Chelating extraction of heavy metals has been proposed as a remediation technique for contaminated soils. A useful method was developed, which assessed 190 ligands for their ability in extraction and recovery of target metals, including cadmium, copper, lead, mercury, nickel, and zinc. Chelator performance was evaluated based on equilibrium calculations with an emphasis on the potential of recovering both the metals and chelating agents. Batch equilibration experiments over 24-h periods were performed to test three chelating agents, S-carboxymethyl-cysteine (SCMC), N-2-acetamidoiminodiacetic acid (ADA), and pyridine-2,6-dicarboxylic acid (PDA), which were deemed suitable for the extraction of cadmium, copper, lead, and zinc from soil. All three chelators demonstrated high extraction capability toward their respective target metals across a wide range of pH, metal, and ligand concentrations. In addition, all three chelators exhibited good recovery potential at moderately elevated pH values. The potential of many chelating agents and their effective pH ranges in the remediation of soils contaminated with heavy metals are reported. Key words: heavy metal, soil, contamination, chelation, remediation.

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