Removal of methyl violet from aqueous solution using a stevensite-rich clay from Morocco

Elass, K; Laachach, A.; Alaoui, Abdellah; Azzi, M.

doi:10.1016/j.clay.2011.07.019

Cited by 90 publications

(33 citation statements)

References 59 publications

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“…The methyl violet (MV) is a typical example of industrially pertinent toxic cationic dye having a lot of detrimental effects on global lives. It is largely used as a purple dye in textile, leather, paint, in paper industries as tinter to give a visually bright appearance in paper, and testing pH ranges as an acid-base indicator [14,15,[29][30][31]. Most of the reported photocatalytic studies of ZnO are on methylene blue and methyl orange by using UV light of 254 nm radiation.…”

Section: Introductionmentioning

confidence: 98%

Solution grown ZnO rods: Synthesis, characterization and defect mediated photocatalytic activity

Mukhopadhyay

Das

Maity³

et al. 2015

Applied Catalysis B: Environmental

106

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Section: Introductionmentioning

confidence: 98%

Solution grown ZnO rods: Synthesis, characterization and defect mediated photocatalytic activity

Mukhopadhyay

Das

Maity³

et al. 2015

Applied Catalysis B: Environmental

106

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“…The intercept C values of the plots which represent the extent of the boundary layer thickness increased proportionally with the increasing MB concentration, suggesting that the boundary layer effect was greater at higher concentration. The characteristic of this plot has been widely obtained for the adsorption of textile dyes onto suspended clay particles as observed by other workers (Elass et al 2011;Gil et al 2011).…”

Section: Diffusion-based Modelsmentioning

confidence: 69%

Role of bentonite adsorbent sub-layer in the photocatalytic-adsorptive removal of methylene blue by the immobilized TiO2/bentonite system

Ngoh

Nawi

2016

Int. J. Environ. Sci. Technol.

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An immobilized clay composite (BEN-PVAG) on a glass plate (GP) was fabricated using bentonite powder (BEN) and glutaraldehyde cross-linked polyvinyl alcohol (PVAG) as the adsorbent and adhesive, respectively. The immobilized bentonite composite (BEN-PVAG) was characterized using SEM, EDX, FTIR, and BET analysis. The adsorption capacity of BEN-PVAG was examined using methylene blue (MB) as the model pollutant. The results indicated that the adsorption of MB onto BEN-PVAG obeyed pseudo-second-order kinetics. In addition, the adsorption of MB by the immobilized BEN-PVAG was controlled by intra-particle diffusion. In contrast, the adsorption of MB by the suspended BEN-PVAG composite was dominated by film diffusion. The immobilized BEN-PVAG was then applied as the adsorbent sublayer for the fabrication of P-25TiO 2 /BEN-PVAG/GP bilayer system where P-25TiO 2 was deposited as the top layer. The fabricated bilayer system exhibited synergistic photocatalytic-adsorptive removal of MB upon irradiation with a light source, while experiment in the dark yielded only adsorption process. The rate of the synergistic photocatalytic-adsorptive removal of MB by the P-25TiO 2 / BEN-PVAG/GP was 5.3 times faster than the suspended P-25TiO 2 . The result implied the positive impact of the BEN-PVAG adsorbent sub-layer on the immobilized P-25TiO 2 photocatalyst. Most important, the immobilized P-25TiO 2 /BEN-PVAG/GP provided a convenient reuse of the catalyst over time where the treated water could be directly discharged without the need of filtration.

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“…7, a fast rate of adsorption is found in the first 5 min, while equilibrium was attained in about 15 min. Adsorption is higher in the beginning due to the large surface area of adsorbents available for adsorption of the adsorbates; as these sites become occupied, adsorption became less efficient (Elass et al, 2011). Figure 8 shows that an increase in initial caffeine concentration decreases the adsorbed ratio slightly.…”

Section: Resultsmentioning

confidence: 95%

Persimmon Tannin Gel: Formation by Autoxidation and Caffeine Adsorption Properties

Ahmad

Linh

Akimoto

et al. 2013

FSTR

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Water-insoluble gel was prepared from persimmon tannin (PT) solution by the autoxidation process. The gelation reaction proceeded by applying oxygen gas and natural light to the aqueous PT solution, without using harmful reagents or catalysts. Adsorption behavior of the PT gel was assessed using caffeine. Batch adsorption studies were conducted to evaluate the influence of experimental parameters such as contact time, initial concentration of adsorbates, adsorbent dose and temperature. The equilibrium data were analyzed using Freundlich and Langmuir isotherm models. Thermodynamic parameters such as Gibbs free energy, enthalpy, and entropy changes were also calculated, showing that caffeine adsorption on the PT gel is an exothermic process and feasible at lower temperatures. The present results suggest that the PT gel can be used as an effective adsorbent for removing caffeine from solutions.Keywords: adsorption, autoxidation, caffeine, gel, isotherm, persimmon tannin *To whom correspondence should be addressed. E-mail: loahmad@stu.kanazawa-u.ac.jp (L.O. Ahmad) kunimoto@se.kanazawa-u.ac.jp (K. Kimoto) IntroductionTannins are a group of polyphenol compounds that are distributed widely in many plant species, where they serve as defense mechanisms against predators. Persimmon fruits (Diospyros kaki L.) are rich in soluble and non-soluble condensed tannins (proanthocyanidins). Low molecular weight soluble tannins are believed to be responsible for the astringency of the persimmon fruit (Matsuo and Ito, 1978). Tannins are also known to form complexes and precipitates with macromolecules, such as proteins and polysaccharides, alkaloids, and heavy metals (Haslam, 1989).Chemical characterization of persimmon tannin (PT) has long been hampered because of its heterogeneous character and high molecular weight. Matsuo and Ito (1978) first reported on the composition and structure of persimmon condensed tannin. Their proposed structure consists of coupled flavan-3-ols, catechin, catechin-3-O-gallate, gallocatechin, and gallocatechin-3-O-gallate residues as the repeating units, with a molar ratio of 1:1:2:2, respectively. They also showed that the PTs are large molecular weight (ca. 13.8 kDa) polymers belonging to the proanthocyanidin B group, with carbon-carbon interflavan linkages between C-4 of one unit and C-8 (or C-6) of another. According to Xu et al. (2012), the stereochemistry of the flavan-3-ol unit of the PT is mainly 2,3-cis, which corresponds to epi-type catechins as shown in Fig. 1.Kaki-shibu, a fermented product made from the juice of immature astringent persimmons, is an important source of condensed tannins traditionally used in tanning paper (fiber hardening) and fishing nets (corrosion prevention), and for removing protein during the brewing of rice wine "sake" and soy sauce in Japan (Sugiura and Subhadrabandhu, 1996). PT gel was used in all adsorption experiments.A stock solution of caffeine (1,000 mg/L) was prepared by dissolving the required amount of caffeine in ultrapure water. The stock solution was ...

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Removal of methyl violet from aqueous solution using a stevensite-rich clay from Morocco

Cited by 90 publications

References 59 publications

Solution grown ZnO rods: Synthesis, characterization and defect mediated photocatalytic activity

Solution grown ZnO rods: Synthesis, characterization and defect mediated photocatalytic activity

Role of bentonite adsorbent sub-layer in the photocatalytic-adsorptive removal of methylene blue by the immobilized TiO2/bentonite system

Persimmon Tannin Gel: Formation by Autoxidation and Caffeine Adsorption Properties

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