scholarly journals Application Research on Stabilizing Treatment of Dredged Sediment

2018 ◽  
Vol 38 ◽  
pp. 02008
Author(s):  
Shi Yannan ◽  
Zhang Chaojie ◽  
Yu Jiongqi ◽  
Tang Mingli
Keyword(s):  
Fly Ash ◽  
Polyvinyl Alcohol ◽  
Sodium Silicate ◽  
Sodium Carbonate ◽  
Water Retention ◽  
Kaolin Clay ◽  
Application Research ◽  
Copper Loss ◽  
Accumulation Index ◽  
Geo Accumulation Index

In order to improve water quality, to ensure the capacity of normal flood discharge and river transport, it carried out a lot of dredging work across the country recently. For harmful sediment’s second pollution and recycling use, this study selected five kinds of sediment. And point A was determined as the research object by using the geo-accumulation index to evaluate the heavy metal. Then the sediment was mixed with lime, fly ash, kaolin clay, sodium silicate, sodium carbonate and polyvinyl alcohol as mud stabilizing materials. Experimental research shows that, copper loss of stabilized soil’s toxicity leaching agent reaches more than 95%, and the permeability coefficient was 10-5 cm/s orders of magnitude. In this paper, it ensures GW7 as the best choice of plants experiments, which are 5% fly ash, 1% lime, 3% kaolin clay, 3% sodium silicate, 3% sodium carbonate and 1% polyvinyl alcohol, through the ways of permeability, water retention, SEM and XRD. The scheme effectively stabilizes copper, and keeps the plants as better form than others. But it has different effect on different plants. Thus it should consider planting varieties optimization in actual applications.

Study on the antiseepage mechanism of the PBFC slurry for landfill site

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744087 ◽  
Author(s):  
Guozhong Dai ◽  
Weicheng Shi ◽  
Xiaoshu Jiang ◽  
Guicai Shi ◽  
Yaxing Zhang
Keyword(s):  
Heavy Metal ◽  
Compressive Strength ◽  
Fly Ash ◽  
Polyvinyl Alcohol ◽  
Metal Ions ◽  
Sodium Carbonate ◽  
Heavy Metal Ions ◽  
Landfill Site ◽  
Low Permeability ◽  
Coefficient Of Permeability

In order to develop a kind of slurry with low permeability which has some adsorption and retardation to the pollutants in leachate to be used in antiseepage engineering of leachate for landfill site, experiments based on orthogonal method were performed. The optimal PBFC slurry was selected: bentonite 18–26%, cement 16–24%, fly ash 18–20%, TOJ800-10 water reducing agent 0.01–0.03%, polyvinyl alcohol 0.2–0.8%, sodium carbonate 0.8–1.5% and water 680–780/1000 mL seriflus. The material has good groutability and a concretion stone ratio which is greater than 99.6%. The coefficient of permeability of 28-day concretion body is 0.53 × 10[Formula: see text]–1.86 × 10[Formula: see text] cm/s and the compressive strength is 0.64–1.04 MPa. The slurry has good adsorption and retardation properties. The block rate of NH4-N and phosphorus reached 98.28%, and the block rate of CODCr and BOD5 reached 85.67%. The block rate of Hg, Pb and other heavy metal ions reached 99.8%. The PBFC slurry improved the retardation capability of the pollutants of the leachate at the landfill site by its infiltration sedimentation and adsorption fixation.

scholarly journals Relationship between Moisture Transportation, Efflorescence and Structure Degradation in Fly Ash/Slag Geopolymer

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5550
Author(s):  
Shuaikang Zhou ◽  
Suhua Zhou ◽  
Jiuchang Zhang ◽  
Xin Tan ◽  
Deng Chen
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Sodium Carbonate ◽  
Strength Loss ◽  
Absorption Capacity ◽  
Curved Surface ◽  
Capillary Absorption ◽  
Structure Degradation

The relationship between moisture transportation and efflorescence in sodium hydroxide- or sodium silicate-activated fly ash/slag geopolymers was investigated. The results show that the efflorescence products are sodium carbonate hydrates, mainly composed of natron, heptahydrate, trona and sodium carbonate. The efflorescence induces compressive strength loss, water absorption increases and pore structure degradation in the geopolymer. When the curved surface of a geopolymer cylinder is covered with plastic film, the moisture transportation drives the free alkalis to the top surface to initiate efflorescence. In comparison, the efflorescence occurring on the curved surface of an uncovered geopolymer cylinder results in a more intensive alkalinity loss. For the uncovered geopolymers prepared with sodium hydroxide activator, efflorescence deposits are formed on the lower half of cylinder. A low capillary absorption capacity developed in the pore structure can only drive the moisture to the middle of cylinder, which is confronted with the drying front. More efflorescence products are formed on the upper half of the uncovered geopolymer cylinder prepared with sodium silicate activator. A relatively higher capillary absorption capacity, developed in the more compact pore structure, transports the moisture from the bottom to the top of cylinder, so no drying line is observed in the cylinder.

The Effect of Dry Mix Sodium Hydroxide onto Workability and Compressive Strength of Geopolymer Paste

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
A. Z. Mohd Ali ◽  
◽  
N. A. Jalaluddin ◽  
N. Zulkiflee ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
High Emission ◽  
New Material ◽  
Curing Regime ◽  
Solid Form ◽  
Geopolymer Paste

The production of ordinary Portland cement (OPC) consumes considerable amount of natural resources, energy and at the same time contribute in high emission of CO2 to the atmosphere. A new material replacing cement as binder called geopolymer is alkali-activated concrete which are made from fly ash, sodium silicate and sodium hydroxide (NaOH). The alkaline solution mixed with fly ash producing alternative binder to OPC binder in concrete named geopolymer paste. In the process, NaOH was fully dissolved in water and cooled to room temperature. This study aims to eliminate this process by using NaOH in solid form together with fly ash before sodium silicate liquid and water poured into the mixture. The amount of NaOH solids were based on 10M concentration. The workability test is in accordance to ASTM C230. Fifty cubic mm of the geopolymer paste were prepared which consists of fly ash to alkaline solution ratio of 1: 0.5 and the curing regime of 80℃ for 24 hours with 100% humidity were implemented. From laboratory test, the workability of dry method geopolymer paste were decreased. The compressive strength of the dry mix of NaOH showed 55% and the workability has dropped to 58.4%, it showed strength reduction compared to the wet mix method.

Distribution and Contamination Status of Heavy Metals in the Surface Sediments along Western Coast of Bali Strait, Banyuwangi

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Defri Yona ◽  
Syarifah Hikmah Julinda Sari ◽  
Anedathama Kretarta ◽  
Citra Ravena Putri Effendy ◽  
Misba Nur Aini ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Pollution ◽  
Contamination Factor ◽  
Pollution Index ◽  
Western Coast ◽  
Sampling Locations ◽  
Accumulation Index ◽  
Geo Accumulation Index ◽  
Geo Accumulation

This study attempted to analyze the distribution and contamination status of heavy metals (Cu, Fe and Zn) along western coast of Bali Strait in Banyuwangi, East Java. Bali Strait is one of the many straits in Indonesia with high fisheries activities that could potentially contributed to high heavy metal pollution. There were five sampling areas from the north to south: Pantai Watu Dodol, Pantai Kalipuro, Ketapang Port, Pantai Boom and Muncar as the fish landing area. Heavy metal pollution in these locations comes from many different activities such as tourism, fish capture and fish industry and also domestic activities. Contamination factor (CF), geo-accumulation index (Igeo) and enrichment factor (EF) of each heavy metal were calculated to obtain contamination status of the research area. The concentrations of Fe were observed the highest (1.5-129.9 mg/kg) followed by Zn (13.2-23.5 mg/kg) and Cu (2.2-7.8 mg/kg). The distribution of Cu, Fe and Zn showed variability among the sampling locations in which high concentrations of Cu and Zn were higher in Ketapang Port, whereas high concentration of Fe was high in almost all sampling locations. According to the pollution index, contamination factors of Cu, Fe and Zn were low (CF < 1 and Igeo < 1). However, high index of EF (> 50) showed high influence of the anthropogenic activities to the contribution of the metals to the environment. This could also because of the high background value used in the calculation of the index due to the difficulties in finding background value from the sampling areas.Keywords: heavy metals, pollution index, contamination factor, geo-accumulation index, Bali Strait

Geo-Accumulation Index of Heavy Metals in Pond Water Sediment of Raipur

2019 ◽  
Vol 12 (3) ◽  
pp. 733-736 ◽  
Author(s):  
Vinod Jena ◽  
Sanjay Ghosh ◽  
Aditi Pande ◽  
Kresimir Maldini ◽  
Natalija Matic
Keyword(s):  
Heavy Metals ◽  
Pond Water ◽  
Accumulation Index ◽  
Geo Accumulation Index ◽  
Geo Accumulation

Baseline Values for Heavy Metals in Soils on Ny-Alesund, Spitsbergen Island, Arctic: The Extent of Anthropogenic Pollution

2013 ◽  
Vol 779-780 ◽  
pp. 1260-1265 ◽  
Author(s):  
Zhi Ling Hao ◽  
Feng Wang ◽  
Hai Zhen Yang
Keyword(s):  
Heavy Metals ◽  
Principal Component ◽  
Anthropogenic Pollution ◽  
Anthropogenic Contamination ◽  
Index Method ◽  
Metal Contents ◽  
Accumulation Index ◽  
Baseline Values ◽  
Geo Accumulation Index ◽  
Cumulative Sums

Heavy metal contents (Cr, Ni, Cu, Zn, As, Cd, Hg, Pb) have been measured in 40 surface soils on Ny-Alesund, Spitsbergen Island, Arctic, which were in concentrations (in milligrams kilogram1) of 13.3-127 (Cr), 1.72-38.8 (Ni), 7.84-47.3 (Cu), 26.5-123 (Zn), 2.17-9.22 (As), 0-2.4 (Cd), 0.21-0.38 (Hg), 0-129 (Pb). Relative cumulative sums analysis and relative cumulative frequency analysis were used to determine the baseline values for the 8 metals, yielding values of Cr (24.7 mg/kg), Ni (6.24 mg/kg) , Cu (11.5 mg/kg) , Zn (77.3 mg/kg) , As (2.60 mg/kg) , Hg (0.27 mg/kg) , Pb (4.38mg/kg). Geo-accumulation index method was applied in order to determine the extent of anthropogenic contamination. Principal component analysis was put into use aiming to identify the sources of these heavy metals. The results showed that Pb, Cr, Cd and Hg have been significantly elevated in concentration by human activities.

Sodium silicate activated slag-fly ash binders: Part I - Processing, microstructure, and mechanical properties

2018 ◽  
Vol 101 (6) ◽  
pp. 2228-2244 ◽  
Author(s):  
Kaushik Sankar ◽  
Peter Stynoski ◽  
Ghassan K. Al-Chaar ◽  
Waltraud M. Kriven
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Sodium Silicate ◽  
Microstructure And Mechanical Properties ◽  
Activated Slag
Sign in / Sign up

Export Citation Format

Share Document