scholarly journals Effect of co-existing ions on lead leaching behaviour from hardened cement paste

2018 ◽  
Vol 195 ◽  
pp. 01007
Author(s):  
Takumi Nishiwaki ◽  
Shaojun Zhou ◽  
Masaharu Yamasaki ◽  
Yuko Ogawa ◽  
Kenji Kawai
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Cement Paste ◽  
Heavy Metal Ions ◽  
Chloride Solution ◽  
Hardened Cement ◽  
Leaching Tests ◽  
Cement Pastes ◽  
Lead Leaching ◽  
Cacl2 Solution

Recently, in the concrete field, the use of industrial wastes for concrete materials is expected for environmental reasons. However, these wastes may contain hazardous heavy metals. It is well known that cement paste has an ability to fix heavy metal ions, whereas it was also found that absorbed heavy metal ions can easily leach from cement paste in the presence of a CaCl2 solution. The present study aims to investigate the lead leaching behaviours from hardened cement pastes in various chloride solutions by tank leaching tests. The water-to-cement ratios of the cement paste specimens were 0.40 and 0.55. Lead was added to the cement pastes at 1 mass% of cement. Each chloride solution for the tank leaching test had three kinds of concentrations (5%, 10%, and 20%). After the tank leaching tests, the chemical changes of the specimens were analysed to discuss the effect of co-existing ions in the solutions. The results indicate that the cumulative lead leaching amount is related to the types of chloride solution as well as the concentrations of the solutions. The lead leaching amount in the CaCl2 solution was much higher than that in other solutions.

Properties of Cement Paste Using Mine Tailing and Polymer Materials

2009 ◽  
Vol 620-622 ◽  
pp. 623-626 ◽  
Author(s):  
Kyung Nam Kim ◽  
Jin Ho Kim ◽  
Dae Yong Shin ◽  
Beom Goo Lee ◽  
Hyun Park
Keyword(s):  
Heavy Metal ◽  
Compressive Strength ◽  
Metal Ions ◽  
Mine Tailings ◽  
Heavy Metal Ions ◽  
Fluorescence Analysis ◽  
Polymer Materials ◽  
Distilled Water ◽  
Cement Pastes ◽  
X Ray

In this study, mine tailings obtained in a region near to Youngwol Sangdong(Korea) was used to investigate the contamination of heavy metal ions. Some amount of mine tailings and lignin(AE agent) were added in the general cement pastes, of which the compressive strength and leaching rate were investigated. X-ray fluorescence analysis shows that the major constituents of mine tailings are 56.9wt% of SiO2, 10.8wt% of Fe2O3, 11.2wt% of CaO and 11.4wt% of Al2O3, and the major phases are quartz and calcite. In the content of heavy metal ions, the concentration of As ion is the highest as 257.261mg/ℓ. When mine tailings and lignin were added in cement pastes, the compressive strength was higher in the cement pastes adding only lignin. Lignin addition significantly improved the compressive strength of cement pastes by approximately 15% when being cured in distilled water. The compressive strength was lower in the cement pastes adding mine tailings than in the cement pastes not adding. The leaching rates of Cr, Pb and As ion in distilled water were decreased in the cement pastes adding lignin, compared to in the cement pastes not adding. The leaching rates of all heavy metal ions in the cement pastes curing for 28 days were within the maximum permitted limits in KSLT and EPT method. Therefore, it is thought that mine tailings can be used as an ecological material.

scholarly journals Analysis of sorption capacity of natural sorbents in relation to aqueous solutions of heavy metal compounds

2021 ◽  
pp. 111-119
Author(s):  
O. M. Khomenko ◽  
O. V. Yehorova ◽  
O. O. Mysliuk
Keyword(s):  
Heavy Metal ◽  
Wastewater Treatment ◽  
Surface Water ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Sorption Capacity ◽  
Heavy Metal Ions ◽  
Chloride Solution ◽  
Bentonite Clay ◽  
Chemical Processing

The main preconditions emergence of an environmental crisis in the country due to surface water pollution include irrational use of water resources in violation of the environmental requirements, discharge of untreated and insufficiently treated industrial and municipal wastewater into water bodies and inflow of polluting substances from agricultural lands as a result of surface water drainage. The whole set of considered factors leads to depletion and pollution of surface water of Ukraine, reduction of their self-cleaning capacity, degradation, impoverishment and collapse of aquatic ecosystems. Excessive content of heavy metal ions in surface water has a negative impact on the environment, causing acute and chronic diseases. Ingress of such pollutants into surface water is almost entirely due to anthropogenic economic activity. Wastewater from chemical, ferrous and nonferrous metallurgy brings a great amount of such pollutants. Among various methods used for removing heavy metal ions from aqueous media, sorption methods remain one of the most effective and popular, mainly due to the fact that they ensure a high degree of purification at relatively low costs. Along with the adsorbents traditionally involved in these processes, a number of studies and practical implementations with use of natural dispersed minerals as adsorbents were conducted lately. The research aims at studying the sorption capacity and efficiency of natural and modified sorbent such as bentonite clay for purification of aqueous solutions containing heavy metal ions in the form of dissolved compounds and justifying its potential application. It studies the efficiency of wastewater treatment aimed at removing heavy metal ions by the natural clay sorbent of bentonite clays of the Cherkaskyi Deposit (Dashukovskyi deposit). The paper presents a technique for modification of bentonite clay in order to increase its adsorption capacity for heavy metal ions using the following three methods: physical (thermal), chemical (processing with application of Iron(III) chloride solution) and combined (thermal processing of the original sorbent followed by processing with application of Iron(III) chloride solution). It has been experimentally proved that a natural sorbent modified via thermal and chemical processing is characterized by a high absorption capacity to heavy metal ions contained in water solutions, in particular to chromium(VI) ions, copper(II) ions and aluminum(III) ions with the purification degree ranging from 5% to 83%. The highest adsorption rate, 83%, is demonstrated by the combined method of bentonite clay modification, therefore proving the effectiveness of application of environmentally friendly natural sorbents for wastewater treatment processes aimed at removing heavy metal ions. The paper indicates the advantages of wastewater treatment sorption methods allowing removal of pollutants of different origin and any concentration.

Bioadsorption of Multiple Heavy Metal Ions by Rhizophora Apiculate sp. and Elaesis Guineensis sp.

2017 ◽  
Vol 14 (1) ◽  
pp. 15
Author(s):  
M.B. Nicodemus Ujih ◽  
Mohammad Isa Mohamadin ◽  
Milla-Armila Asli ◽  
Bebe Norlita Mohammed
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Removal Efficiency ◽  
Heavy Metal Ions ◽  
Agricultural Waste ◽  
Living Organism ◽  
Heavy Metal Concentration ◽  
Industrial Area ◽  
Electrochemical Treatment ◽  
Chemical Oxidation

Heavy metal ions contamination has become more serious which is caused by the releasing of toxic water from industrial area and landfill that are very harmful to all living organism especially human and can even cause death if contaminated in small amount of heavy metal concentration. Currently, peoples are using classic method namely electrochemical treatment, chemical oxidation/reduction, chemical precipitation and reverse osmosis to eliminate the metal ions from toxic water. Unfortunately, these methods are costly and not environmentally friendly as compared to bioadsorption method, where agricultural waste is used as biosorbent to remove heavy metals. Two types of agricultural waste used in this research namely oil palm mesocarp fiber (Elaesis guineensis sp.) (OPMF) and mangrove bark (Rhizophora apiculate sp.) (MB) biomass. Through chemical treatment, the removal efficiency was found to improve. The removal efficiency is examined based on four specification namely dosage, of biosorbent to adsorb four types of metals ion explicitly nickel, lead, copper, and chromium. The research has found that the removal efficiency of MB was lower than OPMF; whereas, the multiple metals ions removal efficiency decreased in the order of Pb2+ > Cu2+ > Ni2+ > Cr2+.

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).

Utilization of Polysaccharides and their Derivatives in the Removal of Metal Ions: Role and Recent Advancement

2020 ◽  
Vol 13 ◽  
Author(s):  
Rishabha Malviya ◽  
Pramod Sharma ◽  
Akanksha Sharma
Keyword(s):  
Waste Water ◽  
Heavy Metal ◽  
Metal Ions ◽  
Industrial Waste ◽  
Heavy Metal Ions ◽  
Environmental Hazards ◽  
Industrial Waste Water ◽  
Recent Advancement ◽  
Removal Of Metal ◽  
Removal Of Metal Ions

: Manuscript discussed about the role of polysaccharides and their derivatives in the removal of metal ions from industrial waste water. Quick modernization and industrialization increases the amount of various heavy metal ions in the environment. They can possess various disease in humans and also causes drastic environmental hazards. In this review the recent advancement for the adsorption of heavy metal ions from waste water by using different methods has been studied. Various natural polymers and their derivatives are act as effective adsorbents for the removal of heavy metal ions from the waste water released from the industries and the treated water released into the environment can decreases the chances of diseases in humans and environmental hazards. From the literature surveys it was concluded that the removal of heavy metal ions from the industrial waste water was important to decrease the environmental pollution and also diseases caused by the heavy metal ions. Graft copolymers were acts as most efficient adsorbent for the removal of heavy metal ions and most of these followed the pseudo first order and pseudo second order model of kinetics.

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