Heavy Metal Removal and Leaching from Pervious Concrete Filter: Influence of Operating Water Head and Reduced Graphene Oxide Addition
01 Sep 2019-Journal of the Environmental Engineering Division (American Society of Civil Engineers (ASCE))-Vol. 145, Iss: 9, pp 04019049
TL;DR: In this paper, the effects of an operating water head (OWH) and reduced graphene oxide (RGO) addition on the pervious concrete filter (PCF) and heavy metals interaction were investigated.
Abstract: The effects of an operating water head (OWH) and reduced graphene oxide (RGO) addition on the pervious concrete filter (PCF) and heavy metals interaction were investigated in the present st...
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TL;DR: In this paper , the effects of initial concentration, contact time and competing ions on heavy metal removal using porous concrete are discussed and the effect of decalcification, atmospheric carbonation, acid influent and acid-influent on heavy metals removal is reviewed.
15 citations
TL;DR: In this paper , new enhanced infiltration materials (construction waste brick, coal gangue, activated carbon, multilayer carbon nanotube, multi-layer graphene) were applied in PPS and the control efficiency and mechanism of typical heavy metals (HMs, Mn2+, Pb2+, Zn2+, Cu2+, Cd2+, Ni2+) was investigated in runoff.
1 citations
TL;DR: In this paper , the properties of metakaolin (MK) based cement paste coating and the effects of the metakolin on removing methylene blue in water were investigated, and the results showed that the fluidity of the cement paste decreased and the cohesiveness increased with increase of the content of MK.
1 citations
TL;DR: In this paper , the impact of aggregate gradation band width and cement to aggregate ratio on the performance of conventional PC and recycled aggregate based pervious concrete (RPC) was analyzed.
Abstract: The present research particularly focuses to understand the synergistic effect of aggregate gradation band width and cement to aggregate ratio on the performance of conventional PC (CPC) and recycled aggregate based pervious concrete (RPC). Four various aggregate gradation bands, such as GB (22.5–4.75 mm), GB (22.5–10.0 mm), GB (22.5–12.5 mm) and GB (22.5–16.0 mm), and two different cement to aggregate ratios, such as 0.33 and 0.20, were used in this study. The research outcome inferences that the aggregate gradation band width and cement aggregate ratios have a great effect on the compressive strength, density, permeability and macroscopic pore characteristics of conventional PC and RPC. When using low cement to aggregate ratio of 0.20 along with these gradation bands, the compressive strength of CPC and RPC was found in the range of 6.34–12.89 MPa and 5.49–12.97 MPa, at the same while, the permeability of CPC and RPC was found in the range of 0.35–1.27 cm/s and 0.60–1.29 cm/s respectively and these values were also satisfied with in the limits as prescribed by ACI-522R-10. This paper elucidates the consensus behaviour of CPC and RPC from the material perspective that would enhance the utilization of CPC and RPC in the construction sector.
TL;DR: In this paper , the heavy metal removal in permeable concrete samples based on geopolymer and Portland cement was examined in a study, and their performance when exposed to strong acids and turbid water were also investigated.
Abstract: The permeable pavement efficiently manages stormwater, which is acidic and contains fine sediments and heavy metals exhausted by vehicles driving on this material. The heavy metal removal in permeable concrete samples based on geopolymer and Portland cement was examined in this study. Their performance when exposed to strong acids and turbid water were also investigated. They were able to infiltrate 28 litres of water in 60 min and gained a compressive strength greater than 25 MPa in 2 weeks after casting. However, it was found that its porous structure was clogged with fine sediments when water containing bentonite clay passed through them for multiple cycles. To evaluate their metal removal capacity, a concentration of 10 mg/l of cadmium-containing solution was passed through such samples for a continuous period of 8 hours. They were able to trap nearly 95% of the cadmium ions from the simulated wastewater during the column experiment. Their adsorption behaviour fits well with the pseudo-second-order kinetic and Langmuir isotherm models, implying that the main removal mechanism is chemisorption. To examine their acid resistance capacities, cement- and geopolymer-based mortar samples were exposed to acids for 2 weeks. The acid-exposed samples were severely degraded, as the mass loss in the geopolymer was determined to be 64% lower than that of the cement sample. Geopolymer-based permeable pavements are ecological, harden in moist air, gain higher strength at early ages, are acid resistant, and also remediate groundwater contamination.
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26,456 citations
TL;DR: It is reported that chemically converted graphene sheets obtained from graphite can readily form stable aqueous colloids through electrostatic stabilization, making it possible to process graphene materials using low-cost solution processing techniques, opening up enormous opportunities to use this unique carbon nanostructure for many technological applications.
Abstract: Graphene sheets offer extraordinary electronic, thermal and mechanical properties and are expected to find a variety of applications. A prerequisite for exploiting most proposed applications for graphene is the availability of processable graphene sheets in large quantities. The direct dispersion of hydrophobic graphite or graphene sheets in water without the assistance of dispersing agents has generally been considered to be an insurmountable challenge. Here we report that chemically converted graphene sheets obtained from graphite can readily form stable aqueous colloids through electrostatic stabilization. This discovery has enabled us to develop a facile approach to large-scale production of aqueous graphene dispersions without the need for polymeric or surfactant stabilizers. Our findings make it possible to process graphene materials using low-cost solution processing techniques, opening up enormous opportunities to use this unique carbon nanostructure for many technological applications.
8,534 citations
TL;DR: In this paper, the state of the field of nanotechnology in concrete is reviewed and the impact of recent advances in instrumentation and computational materials science and their use in concrete research is discussed.
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TL;DR: Potential application of GO in analytical chemistry as a solid sorbent for preconcentration of trace elements and in heavy metal ion pollution cleanup results from its maximum adsorption capacities that are much higher than those of any of the currently reported sorbents.
Abstract: The adsorptive properties of graphene oxide (GO) towards divalent metal ions (copper, zinc, cadmium and lead) were investigated GO prepared through the oxidation of graphite using potassium dichromate was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FT-IR) The results of batch experiments and measurements by flame atomic absorption spectrometry (F-AAS) indicate that maximum adsorption can be achieved in broad pH ranges: 3–7 for Cu(II), 5–8 for Zn(II), 4–8 for Cd(II), 3–7 for Pb(II) The maximum adsorption capacities of Cu(II), Zn(II), Cd(II) and Pb(II) on GO at pH = 5 are 294, 345, 530, 1119 mg g−1, respectively The competitive adsorption experiments showed the affinity in the order of Pb(II) > Cu(II) ≫ Cd(II) > Zn(II) Adsorption isotherms and kinetic studies suggest that sorption of metal ions on GO nanosheets is monolayer coverage and adsorption is controlled by chemical adsorption involving the strong surface complexation of metal ions with the oxygen-containing groups on the surface of GO Chemisorption was confirmed by XPS (binding energy and shape of O1s and C1s peaks) of GO with adsorbed metal ions The adsorption experiments show that the dispersibility of GO in water changes remarkably after complexation of metal ions After adsorption, the tendency to agglomerate and precipitate is observed Excellent dispersibility of GO and strong tendency of GO–Me(II) to precipitate open the path to removal of heavy metals from water solution Potential application of GO in analytical chemistry as a solid sorbent for preconcentration of trace elements and in heavy metal ion pollution cleanup results from its maximum adsorption capacities that are much higher than those of any of the currently reported sorbents
690 citations
TL;DR: Graphene oxide (GO) is the product of chemical exfoliation of graphite and is a potential candidate for use as nanoreinforcements in cement-based materials as discussed by the authors.
Abstract: Graphene oxide (GO) is the product of chemical exfoliation of graphite. Due to its good dispersibility in water, high aspect ratio and excellent mechanical properties, GO is a potential candidate for use as nanoreinforcements in cement-based materials. In this paper, GO was used to enhance the mechanical properties of ordinary Portland cement paste. The introduction of 0.05 wt% GO can increase the GO-cement composite compressive strength by 15-33% and the flexural strength by 41-59%, respectively. Scanning electron microscope imaging of the GO-cement composite shows the high crack tortuosity, indicating that the two-dimensional GO sheet may form a barrier to crack propagation. Consequently, the GO-cement composite shows a broader stress-strain curve within the post-peak zone, leading to a less sudden failure. The addition of GO also increases the surface area of the GO-cement composite. This is attributed to increasing the production of calcium silicate hydrate. The results obtained in this investigation suggest that GO has potential for being used as nano-reinforcements in cement-based composite materials.
574 citations