scholarly journals A Feasibility Study on Production of Concrete Blocks Using Treated Municipal Solid Waste Leachate

2021 ◽  
Author(s):  
Negar Esmaeili ◽  
Nima Heidarzadeh
Keyword(s):  
Heavy Metals ◽  
Setting Time ◽  
Control Sample ◽  
Cement Matrix ◽  
Distilled Water ◽  
Complete Replacement ◽  
Acceptable Range ◽  
The World ◽  
Concrete Blocks ◽  
Cement Setting

Abstract Population growth and development have increased the need for drinking water all over the world. Hence, it is required to find an alternative to water in different industries. Concrete represents a remarkable water-consuming industry. The present study investigates whether the treated leachate of municipal landfills can be employed as a substitute for water in the concrete mixing scheme. For this purpose, concrete samples fabricated at different concentrations of treated leachates were compared to the control sample containing distilled water in terms of unconfined compressive strength (UCS) at the ages of 7 and 28 days. The experimental results revealed treated leachate accelerated the cement setting time by nearly 15 min and increased concrete slumping by 16%. The complete replacement of distilled water with treated leachate decreased UCS by 25% (from 50 to 38 MPa). The scanning electron microscope (SEM) and ultrasonic results showed that a rise in the treated leachate content of concrete increased porosity. Increased porosity would reduce UCS. The presence of heavy metals and leaching from the cement matrix are important characteristics of leachates. The toxicity characteristic leaching procedure (TCLP) revealed that the leaching of heavy metals in all the samples was in the acceptable range.

scholarly journals THE EFFECT OF TUNGSTEN CARBIDE NANOPOWDER AGGLOMERATES ON THE PROPERTIES OF CEMENT MATERIALS

2021 ◽  
Vol 6 (7) ◽  
pp. 8-16
Author(s):  
T. Chayka
Keyword(s):  
Tungsten Carbide ◽  
Bending Strength ◽  
Economic Effect ◽  
Setting Time ◽  
Control Sample ◽  
Maximum Growth ◽  
Cement Matrix ◽  
Cement Stone ◽  
Production Wastes ◽  
Powder Addition

The object of the research is cement samples modified by agglomerates of tungsten carbide nanopowders obtained from carbide waste. The paper considers the influence of tungsten carbide nanopowder on the change in the main cement characteristics (density, water demand, setting time, kinetics of strength gain, compressive strength, bending strength). The optimum additive content in cement materials is 3%. This parameter is estimated by the maximum growth of compressive and flexural strength at all stages of hardening. The effect of WC powder additive on the structure of the cement matrix has been shown. Due to the high dispersibility of WC nanopowder, its particles act as additional crystallization centers, fill in the micropores of the cement stone and create a denser and stronger structure. The results of studying the microstructure of the cement stone with additions of WC powder indirectly confirm the results of strength characteristics. The cement-sand samples with the modifier are found to have a denser crystallized cement-sand stone compared to the control sample (without WC powder addition). The conducted researches have shown perspectivity of application of WC nanoparticles agglomerates as modifying additives for cement materials, which can be used in production of special purpose concrete (hydraulic, radioprotective, etc.). The economic effect of the use of WC nanoadditives obtained from hard-alloy production wastes can be obtained due to a reduction in costs at the stages of construction and operation of structures, buildings, structures based on it.

River Soil & Sand Solidified Blocks as Ballast in Beach Protection

2013 ◽  
Vol 779-780 ◽  
pp. 323-326 ◽  
Author(s):  
Jing Min Mao ◽  
Da Feng Gao
Keyword(s):  
Yangtze River ◽  
Setting Time ◽  
Experimental Studies ◽  
Curing Agent ◽  
The Yangtze River ◽  
Environment Protection ◽  
Time Stability ◽  
Alternative Materials ◽  
Concrete Blocks ◽  
Protection Engineering

This paper deals with the feasibility of beach protection project alternative materials - the Yangtze River soil and sand, applies PCSB curing agent to solidify it and to produce beach protection blocks. Experimental studies on the performance of strength, setting time, stability and anti-erosion have been carried out to inquire into the regularity of solidification. Using soil and sand curing blocks instead of concrete blocks in the application of Yangtze River beach protection engineering has advantages of technology, economy and environment protection etc.

X-Ray Microanalysis of Art Glass Surfaces

2010 ◽  
Vol 18 (5) ◽  
pp. 28-31
Author(s):  
R.B. Simmons
Keyword(s):  
Heavy Metals ◽  
Low Cost ◽  
Metallic Surfaces ◽  
High Quality ◽  
X Ray ◽  
Skin Contact ◽  
Work Area ◽  
The World ◽  
Glass Surfaces ◽  
Glass Workers

In recent years there has been a virtual explosion in the world of art glass. New glass formulations have brought a host of new colors into the marketplace, and the availability of low-cost, high-quality torches and other tools has brought art glass to the hobbyist. In addition to burn risks and possible cutting injury, there are a number of less obvious hazards that should be known to novice glass workers. One of these is the presence of heavy metals in or on glass surfaces and possibly in the atmosphere immediately surrounding the work area, presenting both potential skin contact and inhalation hazards. This study examines the metallic surfaces generated on five glass colors commonly used in art glass jewelry.

The Influence of Purification of Ethyl Acrylate on the Properties of Cement Matrix

2010 ◽  
Vol 150-151 ◽  
pp. 1143-1151
Author(s):  
Chau Lee ◽  
Nian Fu Wang ◽  
Meng Xun Xiem
Keyword(s):  
Hydrogen Peroxide ◽  
Early Stage ◽  
Setting Time ◽  
Ethyl Acrylate ◽  
Cement Matrix ◽  
Strength Development ◽  
Final Setting Time ◽  
Before And After ◽  
Analysis Of Performance ◽  
Acrylate Polymer

This research mainly probes into the analysis of performance and assessment that ethyl acrylate polymer is applied to the cement matrix. The result shows that, before and after the purification, ethyl acrylate can increase the flowability of modified mortar, and with the increasing the dosage of polymer, the flowability is getting better. But if the dosage of hydrogen peroxide used to remove the residua alcohol is excessive, it is easy to cause high mortar viscosity, and that is unfavorable to the flowability. According to the setting time of the mortar under normal consistency, the result shows that the ethyl acrylate before the purification, has retarding effects on both initial and final setting time. With the increasing the dosage of polymer, it takes longer for both setting time. Besides, because hydrogen peroxide has accelerative effect, the purified ethyl acrylate can shorten the setting time of initial and final setting time. However, over dosage of hydrogen peroxide can easily lead to poor strength development in later stage. Using purified ethyl acrylate can overcome the shortcoming of lower strength of 3、7- day early stage. when hydrogen peroxide consumption is 0.5% of the total amount of acid and alcohol, the ethyl acrylate has the positive effect on improving the compressive strength. Finally, among the comprehensive assessments of the mortar testing results, EH0.5-0.1 has the significant effect of modification.

scholarly journals Application areas of phosphogypsum in production of mineral binders and composites based on them: a review of research results

2018 ◽  
Vol 149 ◽  
pp. 01012 ◽  
Author(s):  
Leonid Dvorkin ◽  
Nataliya Lushnikova ◽  
Mohammed Sonebi
Keyword(s):  
Mechanical Properties ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Setting Time ◽  
Industrial Wastes ◽  
Cement Clinker ◽  
Complete Replacement ◽  
Slaked Lime ◽  
The Impact ◽  
Furnace Slag

The increase of the consumption of gypsum products in construction industry with a limited amount of natural gypsum deposits requires alternative sources of gypsum-containing raw materials. In some countries which have fertilizers industry plants, the problem can be solved using industrial wastes, e.g. phosphorgypsum – a byproduct of fertilizers’ production. Kept in dumps over decades, phosphorgypsum is subjected to the chemical changes due to washing out impurities with rain and other natural factors. However, there are observed deviations of harmful impurities in dumped PG depending on its age., Phosphorgypsum of any age requires chemical treatment to neutralize remains of phosphorus and sulfuric acids, fluorine compounds. According to our researches one of the most simple and effective method of neutralization the impurities is using lime-containing admixtures. The paper presents results of laboratory tests of phosphorgypsum as a component of clinker and non-clinker binders. There were investigated the impact of phosphorgypsum as admixture for clinker binders to substitute natural gypsum. Neutralized phosphorgypsum can be applied as mineralizing admixture in calcination of Portland cement clinker. Adding 2 to 2.5% of phosphorgypsum as setting time regulator resulted in a similar physical and mechanical properties compared to mix made with natural gypsum. Another important area of phosphorgypsum application is sulphate activatoion of low-clinker blast-furnace slag cement (clinker content is less than 19%). According to results, the incorporation of phosphorgypsum as sulphate activator in cement has the better effect as natural gypsum. Other development has been carried out to modify the phosphorgypsum binder properties. Complex additive consisted of polycarboxylate-based superplasticizer and slaked lime permitted an increase mechanical properties of hardened phosphorgypsum binder due to significant a reduction of water consumption. Such modified binder can be used as partial or complete replacement of gypsum binder for filling cements and finishing plasters. It can substitute gypsum in non-clinker binders like supersulphated cements. There were also developed compositions of supersulphated cements based on low-alumina blast furnace slag and phosphorgypsum. Supersulphated cements were tested in normal-weight and light-weight concrete.

scholarly journals Cost-effective Method of Analysis for the Determination of Cadmium, Copper, Nickel and Zinc in Cocoa Beans and Chocolates

2014 ◽  
Vol 4 (1) ◽  
pp. 193 ◽  
Author(s):  
Gideon Ramtahal ◽  
Ivan Chang Yen ◽  
Isaac Bekele ◽  
Frances Bekele ◽  
Lawrence Wilson ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Reference Materials ◽  
Certified Reference Materials ◽  
Control Sample ◽  
Cost Effective ◽  
Cocoa Beans ◽  
Copper Nickel ◽  
Flame Atomic Absorption

<p>The determination of heavy metals in cocoa beans and chocolates is of great importance, due to increasingly stringent regulations being implemented by international legislative bodies and chocolate manufacturers, to protect the health of their consumers. While various techniques exist for heavy metal analyses in cocoa, this study developed a cost-effective, accurate and precise method capable of processing up to 120 samples per batch for the determination of cadmium, copper, nickel and zinc. For sample extractions, a normal laboratory hot plate and locally fabricated high-capacity digestion blocks were used, instead of dedicated block digestion or microwave digestion systems. In addition, only concentrated nitric acid was used, instead of mixed reagents used in standardized methods, for metal extractions from samples, with a sample: extractant ratio of 0.5 g : 10 mL, digestion at 130 ºC, followed by filtration and analysis by flame atomic absorption spectrophotometry. The method was validated with Certified Reference Materials, with heavy metal recoveries generally &gt;95%. Additionally, an in-house quality control sample of ground cocoa nib analyzed together with the Certified Reference Materials was used to monitor the consistency of analyses of heavy metals in cocoa bean samples.</p>

scholarly journals Remediation of Pb and Cd Polluted Soils with Fulvic Acid

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1608
Author(s):  
Aslihan Esringü ◽  
Metin Turan ◽  
Asli Cangönül
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Fulvic Acid ◽  
Ornamental Plants ◽  
Polluted Soil ◽  
Green Technology ◽  
Zinnia Elegans ◽  
Fresh Weight ◽  
Polluted Soils ◽  
The World

Heavy metal pollution is among the important environmental problems in the world. Many techniques have already been used to remove the heavy metals such as lead (Pb) and cadmium (Cd). Among them, the phytoremediation method is an environmentally friendly and green technology. This study was carried out to determine the efficiency of fulvic acid (FA) application in removing Pb and Cd from polluted soil using Tagetes eracta L. and Zinnia elegans Jacq. ornamental plants. The results indicated that, FA application, number of flower per plants, and plant fresh weight of Tagetes eracta plants and Zinnia elegans plants increased 187.5%, 104.5% and 155.5%, 57.7%, respectively with application of 7000 mg L−1 FA at 100 mg kg−1 Pb pollution condition, whereas 42.85%, 16.5%, and 44.4–36.1% with application of 7000 mg L−1 FA at 30 mg kg±1 Cd pollution condition, respectively. With the FA application in the Zinnia elegans plant, the root part has accumulated 51.53% more Pb than the shoot part. For Cd, the shoot part accumulated 35.33% more Cd than the root. The effect of FA application on superoxide dismutase (SOD), peroxidase (POD) and, catalase (CAT) of the Tagetes eracta were decreased as 32.7%, 33.1%, and 35.1% for Pb, 21.2%, 25.1%, and 26,1%, for Cd, and 15.1%, 22.7%, and 37.7% for Pb, and 7.55%, 18.0%, and 18.8% for Cd were in Zinnia elegans respectively. In conclusion, Tagetes eracta and Zinnia elegans can not be recommended for remediation of Pb and Cd polluted area, but FA can be recommended for Pb and Cd stabilization in polluted soil.

scholarly journals Use of Non-Traditional Types of Flour in the Flour Culinary Production (Pancakes)

Food Industry ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 33-37
Author(s):  
Vladislav Tiunov ◽  
Olga Chugunova ◽  
Aleksandr Arisov
Keyword(s):  
Wheat Flour ◽  
Raw Materials ◽  
Food Additives ◽  
Control Sample ◽  
Food Products ◽  
Biologically Active ◽  
Optimal Dosage ◽  
Soya Flour ◽  
Complete Replacement ◽  
Biological Value

Currently, Strategy for Improving the Food Products Quality in the Russian Federation until 2030 identifies the need to develop new food products as one of the important state tasks; the quality improvement of raw materials used, the nutritional and biological value of finished products and expanding its range are an urgent area of scientific research. Flour culinary products are no exception. These products made from traditional wheat flour of the highest grade have low nutritional value, high calorie, lack of vitamins and minerals. In order to increase the biological value of flour culinary products, a man adds food additives and biologically active substances; uses non-traditional raw materials for the production. The article considers the possibility of using non-traditional flour types mixtures instead of wheat flour of the highest grade in the production of flour culinary products (pancakes). The researchers developed the optimal dosage for adding mixtures of rice and corn, rice and amaranth, rice and soya flour to the product formulations. They studied comprehensively the regulated indicators of product quality and safety: organoleptic, physical and chemical, microbiological; run the comparative analysis of samples from non-traditional types of flour with a control sample. The authors developed the pancakes technology in the form of baking it in a convection steamer with a complete replacement of wheat flour with a mixture of rice and corn, rice and amaranth, rice and soya flour. They compiled technological maps and formulated a technical document package on the products range.

scholarly journals CONCENTRATION OF HEAVY METALS IN THE SOIL AND PLANTS AROUND WASTE DUMPSITES IN ENUGU METROPOLIS, NIGERIA

2019 ◽  
Vol 3 (1) ◽  
pp. 13
Author(s):  
M. N. Okeke ◽  
Paul Chukwuka Eze ◽  
C. N. Eze
Keyword(s):  
Heavy Metals ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Control Sample ◽  
Control Site ◽  
Soil Samples ◽  
Control Measures ◽  
Plant Sample ◽  
Solid Waste Disposal ◽  
Dump Site

<strong>Aims:</strong> The purpose of this project is to find the concentration of heavy metals (Cu, Zn, Pb, As, Cr, Ni, Cd, Fe and Mn) in the top soil and the plant around the waste dumpsite from Enugu municipal solid waste disposal sites. <strong>Methodology and results: </strong>This was done through collection of soil samples from four designated public municipal solid waste dump sites (Ngwo Umueze, Presidential, New-market and Emene) in Enugu metropolis. The soil samples were collected at 10 metres intervals away from the centre location point of each dump site at constant depth (0 - 15 cm were mixed together and sample picked from it). The samples collection design are as follows: centre (0m) of the dump sites, 10 metres, 20 metres, 30 metres and the control sample which measured 65 metres away from the centre of dumpsites at the same depth. Plant samples were taken just at the centre (0m) and control measures which is at 65 meters distance away from each dump sites. The Goat grasses harvested were taken to the lab to check and analyse its heavy metals intake from the soil. These samples were analysed using atomic absorption spectrophotometer (AA320N) model. On the average, high concentrations of Zn, Fe, Mn, Cu, and Pb were found in the soil samples collected at the centre of the dump sites as 141.70, 121.5, 75.53, 70.33 and 64.53mg/kg respectively. The lower concentrations were obtained in the soil samples taken at the control site which 65 metres distance away from the centre of the four dump sites as 12.00, 81.55, 8.70, 9.56 and 6.51mg/kg for Zn, Fe, Mn, Cu, and Pb respectively. In the plant sample, concentration of Fe (98.00 mg/kg) was found to be the highest in the root at New market dumpsites, while Nil concentration of as (Nil mg/kg) was the least value at Emene from the control distance. <strong>Conclusion, significance and impact study:</strong> SPSS statistical package was used to find out the significant differences between the treatments mean (heavy metals). The result shows that the heavy metals analyses were within the acceptable or permissible limit by WHO/FAO.

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