scholarly journals Study on Solidification of Chromium-Containing Sludge With Alkali Slag Combined With Attapulgite

2021 ◽  
Author(s):  
Huirong Lin ◽  
Linghao Zeng ◽  
Pengpeng Zhang ◽  
Bingquan Jiao ◽  
YanChyuan Shiau ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Compressive Strength ◽  
Cementitious Materials ◽  
Ftir Analysis ◽  
Chemical Immobilization ◽  
Heavy Metal Leaching ◽  
Orthogonal Experiments ◽  
Leaching Toxicity ◽  
Solidified Body

Abstract In order to solve the harm of hazardous waste chromium-containing sludge to humans and the environment, this paper uses attapulgite to strengthen alkali slag to prepare cementitious materials to solidify/stabilize chromium-containing sludge. Single-factor and orthogonal experiments were used to optimize the preparation parameters of alkali slag cementitious materials. The compressive strength, heavy metal leaching toxicity, and microscopic characterization of chromium-containing sludge solidified body were tested to investigate the solidification effect and mechanism of chromium-containing sludge. The results show that: The best content of attapulgite is 4%. The compressive strength of the solidified body decreased with the increase of chromium sludge content, and the leaching concentration of Cr and Cu increased with the rise of chromium-sludge content. The addition of attapulgite enhanced the compressive strength. Compared with the original chromium-containing sludge, the leaching concentration of heavy metals in the solidified body is significantly reduced. The XRD and FTIR analysis showed that the solidified body might solidify/stabilize heavy metals by physical encapsulation of amorphous form and chemical immobilization. This research realizes the use of waste to treat waste and provides the possibility for the application of solidified products in construction.

scholarly journals Recycling of Oily Sludge as a Roadbed Material Utilizing Phosphogypsum-Based Cementitious Materials

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Wei Xiao ◽  
Xiao Yao ◽  
Fuyang Zhang
Keyword(s):  
Heavy Metals ◽  
Compressive Strength ◽  
Pore Structure ◽  
Cementitious Materials ◽  
Solid Particles ◽  
Oily Sludge ◽  
Water Stability ◽  
Volume Stability ◽  
Freeze Thaw ◽  
Stability Performance

Oily sludge is a hazardous waste containing emulsified petroleum hydrocarbons, water, heavy metals, and solid particles. The objective of this work is to employ solidification/stabilization (S/S) techniques to utilize oily sludge as a roadbed material with ordinary Portland cement (OPC), fly ash (FA), and silica fume (SF) as binders and phosphogypsum (PG) as a stabilizer. The efficacy of the S/S process is assessed mainly through an unconfined compressive strength (UCS) test and a toxicity leaching test. Road performance, including water stability, freeze-thaw resistance, and volume stability, is also tested on the solidified samples. The mineralogical compositions, microstructures, and pore structure are characterized through X-ray diffractometry (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP). The results show that the addition of 20% binders (OPC : FA : SF = 1 : 0.7 : 0.8) in combination with phosphogypsum to the oily sludge not only increases the 28-day compressive strength of the solidified samples and remarkably decreases the release of heavy metals but also refines the pore structure and compacts the microstructure. The solidified body had sufficient strength and good water stability performance, freeze-thaw resistance, and volumetric stability. This solidification/stabilization (S/S) process, which combines oily sludge treatment and phosphogypsum resource utilization, significantly enhances environmental protection and renders the solidified product economically profitable.

Immobilization of MSWI Fly Ash with Geopolymers

2010 ◽  
Vol 150-151 ◽  
pp. 1564-1569 ◽  
Author(s):  
Man Tong Jin ◽  
Cai Ju Huang ◽  
Liang Chen ◽  
Xin Sun ◽  
Lian Jun Wang
Keyword(s):  
Heavy Metals ◽  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Silicate Solution ◽  
Waste Incineration ◽  
Silicate Solution ◽  
Hazardous Wastes ◽  
Municipal Solid Waste Incineration ◽  
Mswi Fly Ash ◽  
Solidified Body

The geopolymer was chosen to immobilize the municipal solid waste incineration (MSWI) fly ash because of its strong fixing capacity for heavy metals. The fly ash-based geopolymer was synthesized from metakaolinite with MSWI fly ash under activation of sodium silicate solution, and then cured at relative humidity (RH) between 40% and 90% at 20°C. The ability of immobilization of heavy metals in MSWI fly ash with the geopolymer was evaluated in terms of the compressive strength and leaching concentration. The experimental results confirmed that the compressive strength of the resulting solidified body could achieve 35.13 MPa after 7 days of curing. Meanwhile, the leaching concentrations of Pb, Zn, Cu and Cr were 0.0230 mg/kg, 0.186 mg/kg, 0.231 mg/kg, and 6.56 mg/kg, respectively. We confirm that geopolymerisation is an effective alternative in the disposal of various hazardous wastes containing heavy metals.

Effects of Basicity (CaO/SiO2) on the Behavior of Heavy Metals from Sludge Incineration Ash by Vitrification Treatment

2014 ◽  
Vol 878 ◽  
pp. 284-291 ◽  
Author(s):  
Zhi Kun Zhang ◽  
Ai Min Li ◽  
Xuan Ye Liang
Keyword(s):  
Heavy Metals ◽  
Extraction Procedure ◽  
Residual Fraction ◽  
Test Results ◽  
Bcr Sequential Extraction ◽  
Heavy Metal Leaching ◽  
Sludge Incineration ◽  
Leaching Toxicity ◽  
Regulatory Standard ◽  
Strong Capacity

Heavy metals are one of the important factors that need to be considering for the disposal of sludge incineration ash. Vitrification by melting has been identified as a potentially effective tool that can solidify the heavy metals into the glass matrix structure. In this paper, the characteristics of heavy metals in sludge incineration ash (SIA) were studied by using Community Bureau of Reference (BCR) sequential extraction procedure. Fractions extracted by the BCR sequential procedure were acid soluble/exchangeable, reducible, oxidizable and residual fraction, respectively. The total contents of Cu were the highest, followed by then Zn, Cr and Ni, and the content of Pb was the least. The effects of basicity (CaO/SiO2) on the solidification efficiency of heavy metals and the leaching toxicity of obtained molten slag were investigated. The molten slags demonstrated strong capacity on the stabilization/ solidification of heavy metals. With the basicity value increasing from 0.4 to 0.8, the solidification efficiency of Cu, Zn, Pb and Ni decreased first and then increased, while that of Cr decreased straightly. The heavy metal leaching test results of the molten slags were far lower than the limits required by the regulatory standard of EPA, confirming the possibility of engineering and construction applications.

scholarly journals Residual and ecological risk assessment of heavy metals in fly ash from co-combustion of excess sludge and coal

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yao Tang ◽  
Jingshi Pan ◽  
Biqing Li ◽  
Suying Zhao ◽  
Liguo Zhang
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Ecological Risk ◽  
Fine Particles ◽  
Total Concentration ◽  
Excess Sludge ◽  
Leaching Toxicity ◽  
Main Fraction ◽  
Total Concentrations

AbstractCo-combustion of municipal excess sludge (ES) and coal provides an alternative method for disposing ES. The present study aims to investigate the residual and ecological risk of heavy metals in fly ash from co-combustion of ES and coal. The total concentration and speciation distribution of heavy metals, characterization of SEM, EDX, XRD and leaching test were carried out to assess the fly ash in this study. The results showed that the total concentrations of Cu, Zn and Mn were higher than others in fly ash, and most heavy metals were concentrated in fine particles. For Cd, Cr and Pb, the percentages of speciation of F4 and F5 were all over 90%, suggesting the relatively lower leaching toxicity. The leaching percent of all heavy metals was lower than 5% by two diluted HNO3 solutions for fly ash. The potential ecological risks increased with the decrease of particle size of fly ash, and Cd accounted for the main fraction for ecological risk despite of lower concentration in comparison to other measured heavy metals.

scholarly journals Immobilization of Heavy Metals in Boroaluminosilicate Geopolymers

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 214
Author(s):  
Piotr Rożek ◽  
Paulina Florek ◽  
Magdalena Król ◽  
Włodzimierz Mozgawa
Keyword(s):  
Mechanical Properties ◽  
Heavy Metals ◽  
Heavy Metal ◽  
Compressive Strength ◽  
Phase Composition ◽  
Molar Ratio ◽  
Metal Leaching ◽  
Heavy Metal Leaching ◽  
Composition Structure ◽  
Structure And Microstructure

Boroaluminosilicate geopolymers were used for the immobilization of heavy metals. Then, their mechanical properties, phase composition, structure, and microstructure were investigated. The addition of borax and boric acid did not induce the formation of any crystalline phases. Boron was incorporated into the geopolymeric network and caused the formation of N–B–A–S–H (hydrated sodium boroaluminosilicate) gel. In the range of a B/Al molar ratio of 0.015–0.075, the compressive strength slightly increased (from 16.1 to 18.7 MPa), while at a ratio of 0.150, the compressive strength decreased (to 12 MPa). Heavy metals (lead and nickel) were added as nitrate salts. The loss of the strength of the geopolymers induced by heavy metals was limited by the presence of boron. However, it caused an increase in heavy metal leaching. Despite this, heavy metals were almost entirely immobilized (with immobilization rates of >99.8% in the case of lead and >99.99% in the case of nickel). The lower immobilization rate of lead was due to the formation of macroscopic crystalline inclusions of PbO·xH2O, which was vulnerable to leaching.

scholarly journals Portland blended cements: demolition ceramic waste management

2017 ◽  
Vol 67 (325) ◽  
pp. 114 ◽  
Author(s):  
M. A. Trezza ◽  
S. Zito ◽  
A. Tironi ◽  
E. F. Irassar ◽  
V. F. Rahhal
Keyword(s):  
Compressive Strength ◽  
Cementitious Materials ◽  
Pozzolanic Activity ◽  
Supplementary Cementitious Materials ◽  
Early Age ◽  
Blended Cements ◽  
Ceramic Waste ◽  
Materials Used ◽  
Potential Use

Demolition ceramic wastes (DCWs) were investigated in order to determine their potential use as supplementary cementitious materials in Portland Blended Cements (PBCs). For this purpose, three ceramic wastes were investigated. After characterization of the materials used, the effect of ceramic waste replacement (8, 24 and 40% by mass) was analyzed. Pozzolanic activity, hydration progress, workability and compressive strength were determined at 2, 7 and 28 days. The results showed that the ground wastes behave as filler at an early age, but as hydration progresses, the pozzolanic activity of ceramic waste contributes to the strength requirement.

scholarly journals Production and Characterization of Paper Board Mill ETP Sludge Derived Hydrochar

2021 ◽  
pp. 1-8
Author(s):  
K. Sabarish ◽  
S. Paul Sebastian ◽  
M. Maheswari ◽  
P. Balasubramaniam ◽  
J. Ejilane
Keyword(s):  
Heavy Metals ◽  
Hydrothermal Carbonization ◽  
Sem Analysis ◽  
Molecular Surface ◽  
Point Of Zero Charge ◽  
Ftir Analysis ◽  
Porous Network ◽  
Structural Morphology ◽  
Zero Charge

Hydrothermal Carbonization an emerging technology for the conversion of biomass into carbon rich materials called as hydrochar. In this study, the paper board mill ETP sludge has been used for the production of hydrochar. The characterization of point of zero charge, Heavy metals, proximate and ultimate constituents, structural morphology (SEM), and molecular surface functionalities (FTIR) were also analysed. The results of Hydrochar showed slightly acidic pH (6.40), EC (1.33), and the pHPZC (point of zero charge) of 7.8 and the heavy metals content were found to be below detectable limit. FTIR analysis revealed that, the produced hydrochar have oxygen containing functional groups (-OH, C-O-C, -C=O). SEM analysis has the morphological features such as spongy, fuzzy and fluffy porous network on surfaces. These results of hydrochar can be act as an active adsorbent with further activation.

scholarly journals Waste-Based One-Part Alkali Activated Materials

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2911
Author(s):  
Margarida Gonçalves ◽  
Inês Silveirinha Vilarinho ◽  
Marinélia Capela ◽  
Ana Caetano ◽  
Rui Miguel Novais ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Microstructural Analysis ◽  
Construction Materials ◽  
Sodium Metasilicate ◽  
High Compressive Strength ◽  
Hardened State ◽  
First Time ◽  
Furnace Slag ◽  
Alkali Activated

Ordinary Portland Cement is the most widely used binder in the construction sector; however, a very high carbon footprint is associated with its production process. Consequently, more sustainable alternative construction materials are being investigated, namely, one-part alkali activated materials (AAMs). In this work, waste-based one-part AAMs binders were developed using only a blast furnace slag, as the solid precursor, and sodium metasilicate, as the solid activator. For the first time, mortars in which the commercial sand was replaced by two exhausted sands from biomass boilers (CA and CT) were developed. Firstly, the characterization of the slag and sands (aggregates) was performed. After, the AAMs fresh and hardened state properties were evaluated, being the characterization complemented by FTIR and microstructural analysis. The binder and the mortars prepared with commercial sand presented high compressive strength values after 28 days of curing-56 MPa and 79 MPa, respectively. The mortars developed with exhausted sands exhibit outstanding compressive strength values, 86 and 70 MPa for CT and CA, respectively, and the other material’s properties were not affected. Consequently, this work proved that high compressive strength waste-based one-part AAMs mortars can be produced and that it is feasible to use another waste as aggregate in the mortar’s formulations: the exhausted sands from biomass boilers.

scholarly journals Stormwater Runoff Treatment Using Pervious Concrete Modified with Various Nanomaterials: A Comprehensive Review

2021 ◽  
Vol 13 (15) ◽  
pp. 8552
Author(s):  
Vahid Alimohammadi ◽  
Mehdi Maghfouri ◽  
Delaram Nourmohammadi ◽  
Pejman Azarsa ◽  
Rishi Gupta ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Compressive Strength ◽  
Adsorption Capacity ◽  
Removal Rate ◽  
Stormwater Runoff ◽  
Infiltration Rate ◽  
Stormwater Treatment ◽  
Adsorption Mechanisms ◽  
Wide Range ◽  
Adsorption Processes

Clean water is a vital need for all living creatures during their lifespan. However, contaminated stormwater is a major issue around the globe. A wide range of contaminants, including heavy metals, organic and inorganic impurities, has been discovered in stormwater. Some commonly utilized methods, such as biological, physical and chemical procedures, have been considered to overcome these issues. However, these current approaches result in moderate to low contaminant removal efficiencies for certain classes of contaminants. Of late, filtration and adsorption processes have become more featured in permeable concretes (PCs) for the treatment of stormwater. As nanoparticles have vast potential and unique characterizations, such as a higher surface area to cure polluted stormwater, employing them to improve permeable concretes’ capabilities in stormwater treatment systems is an effective way to increase filtration and adsorption mechanisms. The present study reviews the removal rate of different stormwater contaminants such as heavy metals, organic and other pollutants using nanoparticle-improved PC. The application of different kinds of nanomaterials in PC as porous media to investigate their influences on the properties of PC, including the permeability rate, compressive strength, adsorption capacity and mix design of such concrete, was also studied. The findings of this review show that different types of nanomaterials improve the removal efficiency, compressive strength and adsorption capacity and decrease the infiltration rate of PC during the stormwater treatment process. With regard to the lack of comprehensive investigation concerning the use of nanomaterials in PC to treat polluted stormwater runoff, this study reviews 242 published articles on the removal rate of different stormwater contaminants by using PC improved with nanoparticles.

Sign in / Sign up

Export Citation Format

Share Document