Regeneration of spent organoclays after the sorption of organic pollutants: A review

Zhu, Runliang; Zhu, Jianxi; Ge, Fei; Yuan, Peng

doi:10.1016/j.jenvman.2009.06.015

Cited by 70 publications

(36 citation statements)

References 59 publications

(102 reference statements)

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“…The results suggested that once the stable oligomeric and polymeric silicate surface complexes were formed, they could not easily be desorbed by other oxyanions such as As(V) in groundwater. Even during the absorbent regeneration process, the polymeric silicate surface species could not be completely eluted with NaOH or HCl solutions [36]. Due to the large adsorption capacity and polymerization of silicate on surfaces, we deduce the formation of silicate oligomer and polymer could be one of the most important reasons why most of the groundwater As absorbents were exhausted after two or three times of regeneration [5][6][7].…”

Section: As(v) Pre-adsorption Systemmentioning

confidence: 92%

Polymerization of silicate on TiO2 and its influence on arsenate adsorption: An ATR-FTIR study

Yan

Duan

2015

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Section: As(v) Pre-adsorption Systemmentioning

confidence: 92%

Polymerization of silicate on TiO2 and its influence on arsenate adsorption: An ATR-FTIR study

Yan

Duan

2015

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…The understanding of the effect of thermal pre-treatment of organoclays on their capability to interact with organic substances could be also useful for thermal regeneration of organoclays exploited in removal of organic pollutants from water (Zhu et al 2009). So, the thermal treatment of different organoclays in the inert nitrogen atmosphere was shown to result in a high extent of organoclay regeneration after use for sorption of organic pollutants from water (Lin and Cheng 2002).…”

Section: Introductionmentioning

confidence: 99%

Mild pre-heating of organic cation-exchanged clays enhances their interactions with nitrobenzene in aqueous environment

et al. 2010

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Aqueous sorption kinetics and equilibrium isotherms of nitrobenzene were studied on two series of sorbents that were prepared by (i) replacing inorganic exchangeable cations in Wyoming bentonite with tetraethylammonium (TEA) and benzyltrimethylammonium (BTMA) and (ii) heating synthesized complexes in air at different temperatures (between 150 and 420°C). The aim of this work was to examine recently observed enhancement of aqueous sorption of a probe organic sorbate on organoclays after mild thermal pre-treatment of sorbents. Thermal pretreatment of TEA-and BTMA-clays at 150°C results in the maximal enhancement of nitrobenzene-sorbent interactions as compared with treatment of original bentonite and its exchange complexes formed with long-chain quaternary ammonium (n-hexadecyltrimethylammonium, HDTMA). Based on C, N content data and FTIR spectra of TEAand BTMA-clay complexes, no indications of decomposition of organic matter were found in organoclays heated at 250°C (and below this temperature). Suppressed hydration of pre-heated sorbents resulting in a lessening of waterorganic sorbate competition for sorption sites is considered to be responsible for thermally induced enhancement of nitrobenzene-sorbent interactions. In the HDTMA-based organoclays, the long-chain aliphatic groups of the quaternary ammonium can additionally interact with clay surface thus competing with organic sorbate-sorbent surface inter-M. Borisover ( ) · N. Bukhanovsky actions and, in this way, mitigating the enhancement of nitrobenzene sorption on thermally treated sorbents.

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“…However, none of these studies demonstrated the application of these sorbents in filtration columns, which is the most probable mode in which any candidate sorbent will be applied and compared with other sorbents [34]. Furthermore, in many cases, the limiting factor in applying such sorbents is their inefficient reuse [38,39] since the regeneration should selectively remove the pollutant while the polymer must remain intact. Hence, this challenge has yet to be properly resolved [38].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, in many cases, the limiting factor in applying such sorbents is their inefficient reuse [38,39] since the regeneration should selectively remove the pollutant while the polymer must remain intact. Hence, this challenge has yet to be properly resolved [38]. …”

Section: Introductionmentioning

confidence: 99%

Designing a regenerable stimuli-responsive grafted polymer-clay sorbent for filtration of water pollutants

Gardi

Mishael

2018

Science and Technology of Advanced Materials

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A novel, stimuli-responsive composite, based on poly(4-vinylpyridine) (PVP) brushes, end-grafted to montmorillonite clay (GPC), was designed as a regenerable sorbent for efficient removal of pollutants from water. We characterized the novel composite sorbent and its response to pH, employing Fourier transform infrared, X-ray photoelectron spectroscopy, X-ray diffraction, thermogravimetry analysis and zeta potential measurements. In comparison with conventional, electrostatically adsorbed PVP composites (APC), the GPC presented superior characteristics: higher polymer loading without polymer release, higher zeta potential and lower pH/charge dependency. These superior characteristics explained the significantly higher removal of organic and inorganic anionic pollutants by this composite, in comparison with the removal by APC and by many reported sorbents. For example, the filtration (20 pore volumes) of selenate by GPC, APC and a commercial resin column was complete (100%), negligible (0%) and reached 90% removal, respectively. At low–moderate pH, the grafted polymer undergoes protonation, promoting pollutant adsorption, whereas at high pH, the polymer deprotonates, promoting pollutant desorption. Indeed, ‘in-column’ regeneration of the GPC sorbents was achieved by increasing pH, and upon a second filtration cycle, no reduction in filter capacity was observed. These findings suggest the possible applicability of this stimuli-responsive sorbent for water treatment.

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Regeneration of spent organoclays after the sorption of organic pollutants: A review

Cited by 70 publications

References 59 publications

Polymerization of silicate on TiO2 and its influence on arsenate adsorption: An ATR-FTIR study

Polymerization of silicate on TiO2 and its influence on arsenate adsorption: An ATR-FTIR study

Mild pre-heating of organic cation-exchanged clays enhances their interactions with nitrobenzene in aqueous environment

Designing a regenerable stimuli-responsive grafted polymer-clay sorbent for filtration of water pollutants

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