Performance and mechanism of Cr(VI) removal by zero-valent iron loaded onto expanded graphite

Xu, Congbin; Yang, Wenjie; Liu, Weijiang; Sun, Hongliang; Jiao, Chunlei; Lin, Aoxiang

doi:10.1016/j.jes.2017.11.003

Cited by 110 publications

(21 citation statements)

References 41 publications

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“…The tablet was placed in the sample chamber of the Fourier infrared spectrometer (EQUINOX55; Bruker, Germany). The scan range was 400–4,000 cm −1 (Xu et al, ).…”

Section: Methodsmentioning

confidence: 99%

Effect on sludge disintegration by EDTA‐enhanced thermal‐alkaline treatment

Liu

Jin

Liu

et al. 2019

Water Environment Research

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Sludge disintegration is an effective pretreatment to enhance the biodegradability of sludge. At present, the thermal-alkaline is one of the most commonly used methods, but it has a massive consumption of energy and chemical reagents. EDTA-enhanced thermal-alkaline treatment was used to strengthen the dewatered sludge disintegration at mid-low temperature in this study. Results showed that the dissolving-out quantity of soluble chemical oxygen demand and the volatile solid (VS) in residual sludge in the EDTA-added group were 14.7% higher and 7% lower than those in control system without EDTA, respectively, indicating that EDTA addition improved the performance of sludge disintegration. The addition of EDTA loosened the floc structure and enhanced the hydrolyzability of dissolved organic matters (DOM) with a narrower distribution of the relative molecular weight. The membrane damage of microbial cells in EDTA-added group reached 73.3% after 120 min, which was much higher than that in the control group (31.9%). EDTA contains a large number of hydrogen bond acceptors and could form hydrogen bonds with alcohols and phenols in solubilization products and DOM. It was speculated that the mechanism of EDTA-enhanced sludge disintegration was related to the formation of hydrogen bonds between EDTA and organic matter inside and outside the cell. © 2019 Water Environment Federation • Practitioner points• The addition of EDTA facilitated the thermal-alkali cracking of dewatered sludge. • EDTA increased the particle size of sludge and enhanced the hydrolysis of DOM. • The strengthening effect mainly occurred at the beginning of TB-EPS dissolving slowly. • Hydrogen bond played important roles in the enhanced disintegration of sludge by EDTA.

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“…The tablet was placed in the sample chamber of the Fourier infrared spectrometer (EQUINOX55; Bruker, Germany). The scan range was 400–4,000 cm −1 (Xu et al, ).…”

Section: Methodsmentioning

confidence: 99%

Effect on sludge disintegration by EDTA‐enhanced thermal‐alkaline treatment

Liu

Jin

Liu

et al. 2019

Water Environment Research

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“…The band at 1,434 cm À1 , assigned to the symmetric and asymmetric bending of the C-H bond, may be ascribed to the ethanol added for FeON synthesis and storage (Qiu et al 2011;Ayob & Abdullah 2012). The broad peak at 928 cm À1 arises from the bending vibrations of O-Fe-O groups (Jayarathna et al 2015), and the narrow band around 575 cm À1 represents the Fe-O vibrations of magnetite nanoparticles (Xu et al 2018).…”

Section: Ft-ir Analysismentioning

confidence: 99%

Defluoridation of calcium-rich groundwater using iron oxide nanoparticles

Sudasinghe

Jayaweera

Gunawardana

et al. 2019

Water Practice and Technology

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It has been suggested that moderate to high fluoride ion concentrations in the presence of calcium in groundwater can represent human health hazards resulting in possible lesions in tubular cells, leading to chronic kidney disease of unknown etiology (CKDu). This study focuses on fluoride removal in the presence of calcium using iron oxide nanoparticles (FeONs) as an effective adsorbent in single- and multi-solute batch-studies. Fluoride and calcium removal by FeONs in single-solute batch-studies occurred only by adsorption. Both species followed the Langmuir isotherm model and pseudo second-order kinetics, indicating monolayer adsorption and chemisorption, respectively. In multi-solute batch-studies, fluoride removal was attributed to adsorption and chemical precipitation forming CaF2 in almost similar magnitude. For calcium removal in multi-solute studies, adsorption, co-precipitation, and precipitation were the prominent mechanisms, with co-precipitation dominant. Thus, FeONs are effective in fluoride removal by adsorption in both the presence and absence of calcium. FeONs could also be used successfully year-round in tropical climates, where calcium levels vary substantially, to lessen the risk of CKDu.

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“…The removal isotherms were tted using the Langmuir and Freundlich isotherm models. The Langmuir isotherm model is described by eqn (5…”

Section: Isothermal Adsorption Experimentsmentioning

confidence: 99%