scholarly journals Experimental Study on Solidification of Pb2+ in Fly Ash-Based Geopolymers

2021 ◽  
Vol 13 (22) ◽  
pp. 12621
Author(s):  
Fang Liu ◽  
Ran Tang ◽  
Baomin Wang ◽  
Xiaosa Yuan
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Fly Ash ◽  
Heavy Metal Ions ◽  
Test Results ◽  
Good Resistance ◽  
Domestic Waste ◽  
Before And After ◽  
Better Than ◽  
Solidified Body

Fly ash from the incineration of domestic waste contains heavy metals, which is harmful to the environment. To reduce and prevent their contamination, heavy metal ions need to be sequestered. In this study, the geopolymer prepared by fly ash, a kind of power plant waste, is used to cure the heavy metal Pb2+, and to investigate the effect of different concentrations of Pb2+ on the compressive strength of the solidified body at different ages; the curing effect is judged by the toxic leaching concentration of heavy metals; the resistance of the solidified body to immersion is evaluated by comparing the change in strength before and after leaching; the fly ash-based geopolymer solidified body is compared with the cement solidified body in terms of curing effectiveness; the properties of the geopolymer and its mechanism of curing heavy metals are explored by microscopic tests. The results show that the fly ash-based geopolymer solidified body has good resistance to immersion; the optimum curing concentration of Pb2+ in fly ash-based geopolymers is 2.0%; compared to pure geopolymers, the strength of the solidified body at 28 d decreases by only 13.0%, and the leaching concentration of Pb2+ is 4.73 mg·L−1, which meets the specification requirements; the curing effect of the fly ash-based geopolymer is better than the cement solidified body; the microscopic test results indicate that the curing of Pb2+ by the fly ash-based geopolymer is a combination of both chemical bonding and physical fixation.

scholarly journals Evaluation of the Leachability of Contaminations of Fly Ash and Bottom Ash from the Combustion of Solid Municipal Waste before and after Stabilization Process

2019 ◽  
Vol 11 (19) ◽  
pp. 5384 ◽  
Author(s):  
Monika Czop ◽  
Beata Łaźniewska-Piekarczyk
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Fly Ash ◽  
Bending Strength ◽  
Salt Content ◽  
Bottom Ash ◽  
Municipal Waste ◽  
High Concentration ◽  
Before And After ◽  
Solid Municipal Waste

The aim of this work was to check the possibility of using a concrete matrix to immobilize contaminants from ash (fly and bottom) originating from the combustion of solid municipal waste. This work presents tests of ash from a Polish incineration plant. Nowadays, the management of ash poses a big problem with respect to the high concentration of contaminants that constitutes an environmental nuisance (heavy metals, chlorides, sulfates, etc.). The excessive leaching of contaminants disqualifies ash from being deposited in landfills for hazardous wastes. Bottom ash following the combustion of solid municipal waste mainly contains calcium (23.81%), chlorine (5.44%) and heavy metal (Σ 11.27 g/kg) compounds, while fly ash is characterized by a high content of chlorine (7.22%) and heavy metals (Σ 7.83 g/kg). In the next stage, two concrete mixtures were designed and prepared, containing 30% of ash from combustion of solid municipal waste. The most advantageous physicomechanical properties had concrete mortars that contained 30% of bottom ash: compressive strength—29.48 MPa, bending strength—1678 kN. The performed tests showed that immobilization of dangerous compounds through the C-S-H phase of the concrete significantly decreases the migration of dangerous substance into the environment and minimizes its toxicity. Approximately 97% of the chloride and sulfate salt content was immobilized, and the heavy metal content was immobilized by the C-S-H phase to a degree of 90%. The results obtained provide the option of conveniently managing dangerous wastes with the use of a tight and durable concrete. In many cases, such technology may constitute the best and the cheapest long-term solution in the waste management economy. It may also fill a market gap in this field.

Study on the Mechanical Properties and Heavy Metal Ions Immobilization Capability of Solidified Body for MSWI Fly Ash with Geopolymer

2021 ◽  
Vol 1036 ◽  
pp. 301-308
Author(s):  
Qing Wang ◽  
Xin Rui Wang ◽  
Hai Cao ◽  
Zhao Yang Ding ◽  
De Yong Kong
Keyword(s):  
Heavy Metal ◽  
Compressive Strength ◽  
Fly Ash ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Waste Incineration ◽  
Raw Material ◽  
Polymerization Reaction ◽  
Mswi Fly Ash ◽  
Solidified Body

In this study, municipal solid waste incineration fly ash (hereinafter called MSWI fly ash) was used as a main raw material, and it was prepared into a solidified body for MSWI fly ash with geopolymer by a single-component chemical alkali excitation method. The results were shown that when the content of MSWI fly ash was 50%, SiO2/Al2O3 was between 3.51-4.04, and Na2O/Al2O3 was between 0.24-0.30, with the increasing of SiO2/Al2O3 and Na2O/Al2O3, the 28d compressive strength of the solidified body showed a trend of increasing first and then decreasing, the maximum 28d compressive strength was 17.7MPa. When SiO2/Al2O3 was 4.04 and Na2O/Al2O3 was 0.30, the minimum leaching concentrations of Pb2+ and Cd2+ were 0.018mg/L and 0.027 mg/L. When the content of MSWI fly ash was increasing, the 28d compressive strength of the solidified body gradually decreased, and the heavy metal ions leaching concentration gradually increased. The result of XRD and FTIR indicated that the MSWI fly ash was involved in the polymerization reaction, and the heavy metal ions in MSWI fly ash were also chemically solidified into the geopolymer structure.

Experimental Study on Influence of Fly Ash in Melting Process on Heavy Metal Speciation

2011 ◽  
Vol 347-353 ◽  
pp. 142-146
Author(s):  
Hao Ran Yuan ◽  
Xiao Bo Wang ◽  
Dan Dan Zhao ◽  
Zeng Li Zhao ◽  
Hai Bin Li ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Experimental Study ◽  
Organic Matter ◽  
Fly Ash ◽  
Metal Speciation ◽  
Melting Process ◽  
Heavy Metal Speciation ◽  
Mn Oxide ◽  
Before And After

The influence of melting process on heavy metal speciation was studied. The results show that although there are different changes of heavy metals Cd, Cu, Mn and Zn after melting process, percentage of residue is increasing and others are decreasing. Before melting process, Pb exists mainly in carbonate, Fe-Mn oxide and organic matter bound fractions and in Fe-Mn oxide bound fraction after the process. The percentage distribution of Cr, As, Ba and Ni are not changed obviously before and after melting. In general, the existence forms of all testing heavy metals trend to more stable speciation after melting process.

scholarly journals Synthesis of Zeolite from Fly Ash and Removal of Heavy Metal Ions from Newly Synthesized Zeolite

2010 ◽  
Vol 7 (4) ◽  
pp. 1200-1205 ◽  
Author(s):  
Parag Solanki ◽  
Vikal Gupta ◽  
Ruchi Kulshrestha
Keyword(s):  
Heavy Metal ◽  
Fly Ash ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Coal Fly Ash ◽  
Proximate Analysis ◽  
13X Zeolite ◽  
Alkali Fusion ◽  
Type Zeolite ◽  
The Cost

Coal fly ash was used to synthesize X-type zeolite by alkali fusion followed by hydrothermal treatment. Characteristics of the various Fly ash samples were carried out. Coal proximate analysis was done. Batch experiment was carried out for the adsorption of some heavy metal ions on to synthesized Zeolite. The cost of synthesized zeolite was estimated to be almost one-fifth of that of commercial 13X zeolite available in the market.

scholarly journals Estimation of the Concentration of Some Heavy Metals in Groundwater in Rutba City

2021 ◽  
Vol 904 (1) ◽  
pp. 012009
Author(s):  
A W Abd Byty ◽  
M A Gharbi ◽  
A H Assaf
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Large Scale ◽  
Toxic Metal ◽  
Scale Production ◽  
Future Health ◽  
Distribution Maps ◽  
Guideline Values

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.

scholarly journals The Influence of Heavy Metal Ions on the Viability and Metabolic Enzyme Activity of the Marbled Crayfish Procambarus virginalis (Lyko, 2017)

2018 ◽  
Vol 70 ◽  
pp. 11-23 ◽  
Author(s):  
Oleg Marenkov ◽  
Mykola V. Prychepa ◽  
Julia Kovalchuk
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Enzyme Activity ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Physiological State ◽  
Metabolic Enzyme ◽  
Nickel Ions ◽  
The Individual ◽  
Marbled Crayfish

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.

Research Progress in Removing Heavy Metals from Waste Water via Bio-Sorption

2014 ◽  
Vol 587-589 ◽  
pp. 692-695
Author(s):  
Wei Sun
Keyword(s):  
Waste Water ◽  
Heavy Metals ◽  
Heavy Metal ◽  
Water Treatment ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Waste Water Treatment ◽  
Research Progress ◽  
Traditional Methods ◽  
Sorption Method

Bio-absorption has an unparalleled advantage over other traditional methods in removing and recycling heavy metal ions from waste water. Consequently, it has a promising future. In this paper, the traditional methods and the bio-sorption method via which heavy metals are removed from waste water are compared to summarize the mechanism of bio-sorption, the types of bio-sorbent, the factors that can influence bio-sorption and the state of its application in waste water treatment .

scholarly journals A systematic study for removal of heavy metals from aqueous media using Sorghum bicolor: an efficient biosorbent

2018 ◽  
Vol 77 (10) ◽  
pp. 2355-2368 ◽  
Author(s):  
Khalida Naseem ◽  
Zahoor H. Farooqi ◽  
Muhammad Z. Ur Rehman ◽  
Muhammad A. Ur Rehman ◽  
Robina Begum ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Aqueous Media ◽  
Review Article ◽  
Isotherm Models ◽  
Adsorption Efficiency ◽  
Adsorption Isotherm Models ◽  
Removal Of Heavy Metals

Abstract This review is based on the adsorption characteristics of sorghum (Sorghum bicolor) for removal of heavy metals from aqueous media. Different parameters like pH, temperature of the medium, sorghum concentration, sorghum particle size, contact time, stirring speed and heavy metal concentration control the adsorption efficiency of sorghum biomass for heavy metal ions. Sorghum biomass showed maximum efficiency for removal of heavy metal ions in the pH range of 5 to 6. It is an agricultural waste and is regarded as the cheapest biosorbent, having high adsorption capacity for heavy metals as compared to other reported adsorbents, for the treatment of heavy metal polluted wastewater. Adsorption of heavy metal ions onto sorghum biomass follows pseudo second order kinetics. Best fitted adsorption isotherm models for removal of heavy metal ions on sorghum biomass are Langmuir and Freundlich adsorption isotherm models. Thermodynamic aspects of heavy metal ions adsorption onto sorghum biomass have also been elaborated in this review article. How adsorption efficiency of sorghum biomass can be improved by different physical and chemical treatments in future has also been elaborated. This review article will be highly useful for researchers working in the field of water treatment via biosorption processing. The quantitative demonstrated efficiency of sorghum biomass for various heavy metal ions has also been highlighted in different sections of this review article.

Removing heavy metals from effluents with natural and modified clay-containing sorbents

2021 ◽  
pp. 30-37
Author(s):  
А.К. Стрелков ◽  
С.В. Степанов ◽  
О.Н. Панфилова ◽  
А.В. Арбузов
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Specific Productivity ◽  
Natural Material ◽  
Main Process ◽  
Tertiary Treatment ◽  
Modified Clay ◽  
Cartridge Filter

Представлены результаты исследований сорбции ионов тяжелых металлов глиносодержащими сорбентами из сточных вод гальванического производства. Цель испытаний, проведенных на пилотной установке, – разработка технологической схемы для доочистки сточных вод от ионов тяжелых металлов и извлечения отработанного сорбента с применением намывного патронного фильтра со слоем перлита. В испытаниях использовались: термически модифицированный сорбент на основе природных материалов – модифицированная глина, а также смесевый сорбент, состоящий из монтмориллонита, торфа и доломита в соотношении 5:4:1 без термической обработки. Исследования проводились по восьми ионам тяжелых металлов в диапазоне низких концентраций, характерных для сточных вод, поступающих на доочистку после отстаивания с корректировкой рН. Основные технологические параметры доочистки: pH8; продолжительность контакта сорбента с обрабатываемыми водами 90 мин, доза сорбентов 1–1,6 г/л. Отделение отработанного сорбента от очищенной воды было предусмотрено в две ступени – отстаиванием и фильтрованием на патронном намывном фильтре. Введение коагулянта «Аква-АуратÔ-30» дозой 40 мг/л по Al2O3 позволило снизить концентрацию взвешенных веществ в осветленных сточных водах, подаваемых на намывные фильтры, до 8 мг/л для модифицированной глины и 15 мг/л для смесевого сорбента. Удельная производительность намывного слоя составила 23 м3/(ч×м2), расчетная удельная нагрузка по взвеси на поверхность фильтра составила для модифицированной глины 850 г/м2, для смесевого сорбента – 680 г/м2. Расчетная продолжительность фазы фильтрования намывного слоя при использовании предварительного реагентного отстаивания составила 4,6 и 2 ч для модифицированной глины и смесевого сорбента соответственно. Обеспечена эффективность очистки сточных вод от ионов тяжелых металлов на уровне ПДК для водных объектов рыбохозяйственного значения. The results of studies of the sorption of heavy metal ions by clay-containing sorbents from plating effluents are presented. The purpose of the tests carried out in a pilot plant was developing a process scheme for the removal of heavy metal ions from effluents and extraction of the spent sorbent in a precoat cartridge filter with a layer of perlite. The materials used in the tests were as follows: thermally modified sorbent based on natural material, i. e., modified clay, as well as mixed sorbent consisting of montmorillonite, peat and dolomite in a ratio of 5:4:1 without heat treatment. The studies were carried out on eight ions of heavy metals in the low concentration range typical for the effluent coming for tertiary treatment after sedimentation with pH adjustment. The main process parameters of tertiary treatment were: pH 8; the duration of the sorbent contact with the effluent was 90 min, the dose of sorbents was 1–1.6 g/l. The separation of the spent sorbent from the effluent was executed in two stages – sedimentation and filtration in a precoat cartridge filter. The addition of Aqua-AuratTM-30 coagulant with a dose of 40 mg/l as Al2O3provided for reducing the concentration of suspended solids in the clarified effluent supplied to the precoat filters to 8 mg/l for modified clay and 15 mg/l for the mixed sorbent. The specific productivity of the alluvial layer was 23 m3/(h‧m2), the specific load of the suspension on the filter surface was 850 g/m2for modified clay, and 680 g/m2 for mixed sorbent. The estimated duration of the filtration phase of the alluvial layer while using preliminary chemical sedimentation was 4.6 and 2 h for the modified clay and mixed sorbent, respectively. The efficiency of removing heavy metal ions from effluents was provided at the level of the maximum permissible concentration for fishery water bodies.

Mechanism of Heavy Metal ATPase (HMA2, HMA3 and HMA4) Genes

2020 ◽  
pp. 104-117
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Heavy Metal Ions ◽  
Metal Tolerance ◽  
Heavy Metal Tolerance ◽  
Land Plant ◽  
Signaling Mechanism ◽  
Metal Transporter ◽  
Metals Tolerance ◽  
Environmentally Sound

Heavy metals are the most important pollutants that are non-biodegradable and increasingly accumulate in the environment. Phytoremediation can be defined as the use of plants for the extraction, immobilization, containment, or degradation of contaminants. It provides an ecologically, environmentally sound and safe method for restoration and remediation of contaminated land. Plant species vary in their capacity of hyper-accumulation of heavy metals. The chapter reviews the current findings on the molecular mechanism involved in heavy metals tolerance, which is a valuable tool for phytoremediation. The heavy metal tolerance genes help in the hyper-accumulation trait of a plant. Heavy metal transporter ATPases (HMAs) genes help in the refluxing of heavy metal ions from the cytosol, either into the apoplast, the vacuole, or other organelles, which help in the hyperaccumulation of metal. Understanding the signaling mechanism of transporter genes will be an important tool to understand the genetics of hyperaccumulation.

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