A new route to fabricate high-efficient porous silicate adsorbents by simultaneous inorganic-organic functionalization of low-grade palygorskite clay for removal of Congo red

Dong, Wei; Lu, Yushen; Wang, Wenbo; Zong, Li; Zhu, Yongfeng; Kang, Yuru; Wang, Aiqin

doi:10.1016/j.micromeso.2018.11.013

Cited by 49 publications

(11 citation statements)

References 64 publications

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“…These agglomerates decrease the adsorption efficiency, because a greater amount of interactions between the adsorbate and the absorbent are required for the adsorption to be effective. On the other hand, negatively charged CR molecules interacted electrostatically with the positively charged surface of the adsorbent at low pH, presenting a higher rate of adsorption [94]. In basic pH, OH − ions promote the deprotonation of the surface and generate -Si-O − groups, which favor the adsorption of the positively charged CV [95].…”

Section: Effect Of Adsorbent Dosagementioning

confidence: 99%

Adsorption Behavior of Acid-Treated Brazilian Palygorskite for Cationic and Anionic Dyes Removal from the Water

et al. 2021

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The effect of acid treatment on the adsorptive capacity of a Brazilian palygorskite to remove the crystal violet (CV) and congo red (CR) dyes was investigated. The raw palygorskite was acid-treated by different HCl solutions (2, 4, and 6 mol/L). The modifications on the palygorskite structure were investigated using X-ray diffraction, X-ray fluorescence, Fourier-transform infrared spectroscopy, N2 adsorption/desorption, and thermogravimetric and differential thermal analysis. The efficiency of CV and CR adsorption was investigated, and the effect of the initial concentration, contact time, pH, and adsorbent amount was analyzed. The results revealed that CV adsorption in the acid-treated palygorskite was higher than that of the raw material. A Langmuir isotherm model was observed for the adsorption behavior of CV, while a Freundlich isotherm model was verified for the CR adsorption. A pseudo-second-order model was observed for the adsorption kinetics of both dyes. The higher CV adsorption capacity was observed at basic pH, higher than 97%, and the higher CR removal was observed at acidic pH, higher than 50%. The adsorption parameters of enthalpy (ΔH), entropy (ΔS), and Gibbs energy (ΔG) were evaluated. The adsorption process of the CV and CR dyes on the raw and acid-treated Brazilian palygorskite was predominantly endothermic and occurred spontaneously. The studied raw palygorskite has a mild-adsorption capacity to remove anionic dyes, while acid-treated samples effectively remove cationic dyes.

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Section: Effect Of Adsorbent Dosagementioning

confidence: 99%

Adsorption Behavior of Acid-Treated Brazilian Palygorskite for Cationic and Anionic Dyes Removal from the Water

et al. 2021

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“…EDS analysis is used to reveal the surface chemical compositions of betanin/Pal and betanin/Hal samples ( Figure S1 ), and their atomic percent with different elements is presented in Figure 1 c,d, respectively. The O, Si, Mg, Al, Fe, and Ca elements are derived from Pal and Hal [ 34 , 51 , 52 ]. Furthermore, the presence of C and N demonstrates the successful loading of betanin on Pal and Hal.…”

Section: Resultsmentioning

confidence: 99%

Fabrication of Eco-Friendly Betanin Hybrid Materials Based on Palygorskite and Halloysite

Wang

et al. 2020

Materials

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Eco-friendly betanin/clay minerals hybrid materials with good stability were synthesized by combining with adsorption, grinding, and heating treatment using natural betanin extracted from beetroot and natural 2:1 type palygorskite or 1:1 type halloysite. After incorporation of clay minerals, the thermal stability and solvent resistance of natural betanin were obviously enhanced. Due to the difference in the structure of palygorskite and halloysite, betanin was mainly adsorbed on the outer surface of palygorskite or halloysite through hydrogen-bond interaction, but also part of them also entered into the lumen of Hal via electrostatic interaction. Compared with palygorskite, hybrid materials prepared with halloysite exhibited the better color performance, heating stability and solvent resistance due to the high loading content of betanin and shielding effect of lumen of halloysite.

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“…Therefore, the cationic CV dye adsorption is less efficient, as there is competition between the H + ions and the CV molecules for the adsorption sites and the repulsive force between the surface of the positively charged adsorbent and the CV molecules decreases the removal efficiency [108]. On the other hand, in an acidic medium, the negatively charged CR molecules interact electrostatically with the positively charged palygorskite surface, presenting a higher adsorption rate [109]. In a basic medium, the OH − ions promote the deprotonation of the palygorskite surface and generate -Si-O − groups [110].…”

Section: Effect Of Ph Variationmentioning

confidence: 99%

Adsorption Behavior of Crystal Violet and Congo Red Dyes on Heat-Treated Brazilian Palygorskite: Kinetic, Isothermal and Thermodynamic Studies

et al. 2021

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The effect of heat treatment on the adsorptive capacity of a Brazilian palygorskite to remove the dyes crystal violet (CV) and congo red (CR) was investigated. The natural palygorskite was calcined at different temperatures (300, 500 and 700 °C) for 4 h. Changes in the palygorskite structure were evaluated using X-ray diffraction, X-ray fluorescence, thermogravimetric and differential thermal analysis, N2 adsorption/desorption and Fourier transform infrared spectroscopy. The adsorption efficiency of CV and CR was investigated through the effect of initial concentration, contact time, temperature, pH and dosage of adsorbent. The calcination increased the adsorption capacity of palygorskite, and the greatest adsorption capacity of CV and CR dyes occurred in the sample calcined at 700 °C (Pal-700T). The natural and calcined samples at 300 and 500 °C followed the Freundlich isothermal model, while the Pal-700T followed the Langmuir isothermal model. Adsorption kinetics results were well described by the Elovich model. Pal-700T showed better adsorption performance at basic pH, with removal greater than 98%, for both dyes. Pal-700T proved to be a great candidate for removing cationic and anionic dyes present in water.

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A new route to fabricate high-efficient porous silicate adsorbents by simultaneous inorganic-organic functionalization of low-grade palygorskite clay for removal of Congo red

Cited by 49 publications

References 64 publications

Adsorption Behavior of Acid-Treated Brazilian Palygorskite for Cationic and Anionic Dyes Removal from the Water

Adsorption Behavior of Acid-Treated Brazilian Palygorskite for Cationic and Anionic Dyes Removal from the Water

Fabrication of Eco-Friendly Betanin Hybrid Materials Based on Palygorskite and Halloysite

Adsorption Behavior of Crystal Violet and Congo Red Dyes on Heat-Treated Brazilian Palygorskite: Kinetic, Isothermal and Thermodynamic Studies

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