Removal of triclosan by CTAB-modified zeolite-rich tuff from aqueous solutions

MRS Advances ◽  
2020 ◽  
Vol 5 (62) ◽  
pp. 3257-3264
Author(s):  
Sonia Alvarez-García ◽  
Guadalupe Macedo-Miranda ◽  
Sonia Martínez-Gallegos ◽  
Eduardo Ordoñez-Regíl ◽  
Jessica López-Castillo ◽  
...  

AbstractTriclosan (TCS) adsorption behavior by a modified zeolite with Cetyl Trimethyl Ammonium Bromide (CTAB) was evaluated factoring in pH, contact time, and TCS initial concentration in a batch system. Natural clinoptilolite-type zeolite from Sonora, Mexico was conditioned with a sodium chloride solution, and, subsequently, modified with CTAB. All the zeolites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Electron Dispersive Spectroscopy (EDS), and the Zero Point Charge (pHZPC). It was found that the morphological and structural properties of natural zeolite were not affected after treatment with cationic surfactant. Furthermore, adsorption process efficiency was enhanced by the presence of CTAB, obtaining TCS maximum adsorption capacity at an optimal pH of 9.0. In this context, the positively charged surface of the modified zeolite and the anionic triclosan species present were decisive. Kinetics data were well adjusted to a pseudo-second order model with a TCS adsorption capacity of 1.430 ± 0.051 mg g-1 at an equilibrium time of 18 h. Isotherm results were best adjusted to the Langmuir model with a qmax = 2.027 mg g-1 using an initial Co concentration of 18.0 mg L-1, and reaching an equilibrium Ce concentration of 0.559 mg L-1. The mechanism for the adsorption of TCS by CTAB-modified zeolite was proposed to be electrostatic attractions between the group of partial positive charge of CTAB and the anionic species of triclosan. Consequently, CTAB-modified zeolites could be used as effective adsorbents for triclosan removal.

2015 ◽  
Vol 713-715 ◽  
pp. 2889-2892
Author(s):  
Chao Lv ◽  
Gui Fang Zhang ◽  
Xing Tian Liu ◽  
Ying Xi Qin ◽  
Lin Shao ◽  
...  

Poly (vinylidene fluoride)/attapulgite (PVDF/ATP) hybrid membrane was prepared for removal of Cr (VI) ions from wastewater with PVDF as matrix and ATP as adsorbent which was functionalized by cetyl trimethyl ammonium bromide (CTAB) and then modified by tannins (TA). The adsorption kinetics and equilibrium isotherms of the hybrid membranes were particular concerned. The results indicated that the PVDF/ATP membrane displayed a good adsorption capacity for Cr (VI) ions, the adsorption equilibrium could be established within 5 hours and the maximum adsorption capacity was 21.4 mg/g. The adsorption kinetics fit well with Lagergren second-order equation and the adsorption isotherms can be well described by Langmuir and Freundlich models.


2021 ◽  
Vol 5 (1) ◽  
pp. 9
Author(s):  
Muhammad Yusuf Prajitno ◽  
Mohamad Taufiqurrakhman ◽  
David Harbottle ◽  
Timothy N. Hunter

Natural clinoptilolite was studied to assess its performance in removing caesium and strontium ions, using both static columns and an agitated tube reactor (ATR) for process intensification. Kinetic breakthrough curves were fitted using the Thomas and Modified Dose Response (MDR) models. In the static columns, the clinoptilolite adsorption capacity (qe) for 200 ppm ion concentrations was found to be ~171 and 16 mg/g for caesium and strontium, respectively, highlighting the poor material ability to exchange strontium. Reducing the concentration of strontium to 100 ppm, however, led to a higher strontium qe of ~48 mg/g (close to the maximum adsorption capacity). Conversely, halving the column residence time to 15 min decreased the qe for 100 ppm strontium solutions to 13–14 mg/g. All the kinetic breakthrough data correlated well with the maximum adsorption capacities found in previous batch studies, where, in particular, the influence of concentration on the slow uptake kinetics of strontium was evidenced. For the ATR studies, two column lengths were investigated (of 25 and 34 cm) with the clinoptilolite embedded directly into the agitator bar. The 34 cm-length system significantly outperformed the static vertical columns, where the adsorption capacity and breakthrough time were enhanced by ~30%, which was assumed to be due to the heightened kinetics from shear mixing. Critically, the increase in performance was achieved with a relative process flow rate over twice that of the static columns.


2016 ◽  
Vol 75 (1) ◽  
pp. 106-114 ◽  
Author(s):  
Lucas Meili ◽  
Társila Santos da Silva ◽  
Daniely Carlos Henrique ◽  
João Inácio Soletti ◽  
Sandra Helena Vieira de Carvalho ◽  
...  

In this work, the potential of ouricuri (Syagrus coronata) fiber as a novel biosorbent to remove methylene blue (MB) from aqueous solutions was investigated. The fiber was prepared and characterized according to the fundamental features for adsorption. A 23 experimental design was used to evaluate the effects of adsorbent dosage (M), fiber diameter (D) and agitation (A) on the adsorption capacity. In the more adequate conditions, kinetic and equilibrium studies were performed. The experimental design results showed that M = 10 g L−1), D = 0.595 mm and A = 200 rpm were the more adequate conditions for MB adsorption. Based on the kinetic study, it was found that the adsorption process was fast, being the equilibrium was attained at about 5 min, with 90% of color removal. The isotherm was properly represented by the Sips model, and the maximum adsorption capacity was 31.7 mg g−1. In brief, it was demonstrated that ouricuri fiber is an alternative biosorbent to remove MB from aqueous media, taking into account the process efficiency and economic viewpoint.


2006 ◽  
Vol 41 (2) ◽  
pp. 210-215 ◽  
Author(s):  
Ching Yuan ◽  
Hsing-Lung Lien

Abstract Removal of As(V) using nanoscale iron particles was examined in batch reactors. Nanoscale iron particles, utilizing zerovalent iron with a diameter less than 100 nm as reactive materials, have been demonstrated to effectively remediate a wide variety of common environmental contaminants. In this study, characterization of nanoscale iron particles and their corrosion products was conducted using SEM-EDX, XRD, BET surface area analyzer and Laser Zee Meter. SEM-EDX results indicated adsorption of arsenic onto the iron surface, and XRD analysis found the formation of iron corrosion products including lepidocrocite, magnetite and/or maghemite at a reaction period of 7 d. Measurements of zeta potential revealed that the nanoscale iron particles have a zero point of charge at pH 4.4. Increasing adsorption amounts of arsenic with decreasing pH can therefore be attributed to the positive surface charge of the particles at lower pH. The maximum adsorption capacity of nanoscale iron particles determined by the Langmuir equation was about 38.2 mg/g. Normalization of the adsorption capacity to specific surface areas provides insight into the importance of iron types and the contact time of reactions in influencing arsenic uptake.


Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1640 ◽  
Author(s):  
Shimaa M. Ali ◽  
Areej A. Eskandrani

La0.9Sr0.1FeO3 perovskite, prepared by the microwave-assisted method, was capped with cetyl trimethyl ammonium bromide (CTAB) cationic surfactant, and applied as a sorbent for the removal of the anionic Congo red (CR) dye from aqueous solutions. X-ray diffraction (XRD) patterns showed that the perovskite structure was not affected by capping; however, the particle size increased. There was a hipsochromic shift in the value of λmax of the CR absorption spectrum in the presence of CTAB, which indicated the formation of an oppositely charged dye–surfactant complex. The adsorption efficiency of CTAB-capped La0.9Sr0.1FeO3 was independent of the pH of the solution—equilibrium was reached after a few minutes. The value of the maximum adsorption capacity, qm, was 151.52 mg·g−1, which was 10-times higher than that of the pure perovskite. The proposed sorbent maintained its excellent sorption ability in the presence of the sample matrix; therefore, it can be regenerated and reused with unchanged performance.


Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 290
Author(s):  
Jesse Y. Rumbo Morales ◽  
Alan F. Perez Vidal ◽  
Gerardo Ortiz Torres ◽  
Alexis U. Salas Villalobo ◽  
Felipe de J. Sorcia Vázquez ◽  
...  

Adsorption processes are characterized by their kinetics and equilibrium isotherms described by mathematical models. Nowadays, adsorption with molecular sieves is a method used to separate certain elements or molecules from a mixture and produce hydrogen, nitrogen, oxygen, ethanol, or water treatment. This study had two main objectives. The first one was focused on the use of different natural (Clinoptilolite-S.L. Potosi, Clinoptilolite-Puebla, and Heulandite-Sonora) and synthetic (Zeolite Type 3A) adsorbents to separate the mixtures H 2 O / H 2 S O 4 and H 2 O / C 2 H 5 O H . It was determined that both Zeolite Type-3A and Heulandite-Sonora have greater adsorption capacity in a shorter time compared with the Clinoptilolites at different temperatures. The second objective was the simulation of a pressure swing adsorption process to dehydrate ethanol using the parameters obtained from Zeolite Type 3A (with maximum adsorption capacity). Several configurations were considered to calculate the appropriate nominal values for the optimal process. The results illustrate that the purity of ethanol is increased when the following parameters are considered in the adsorption process: a high pressure, a constant temperature between 100 and 120 ° C, a feed composition near the azeotropic point with lower water content, and a purge pressure near the vacuum. Finally, the results show that it is possible to take advantage of the length of the absorber bed in order to reduce the energy costs by increasing the ethanol production as well as complying with the international purity standards.


2014 ◽  
Vol 1065-1069 ◽  
pp. 3123-3126
Author(s):  
Gang Chao Zhu ◽  
Jian Xin Shou ◽  
Jia Wei Qian ◽  
Hua Zheng Xin ◽  
Mu Qing Qiu

In this study, sawdust modified by cetyltimethyl ammonium bromide was applied to adsorb conge red in aqueous solutions. The characteristics of modified sawdust were characterized by Fourier transform infrared spectrum and scanning electron microscopy. The effect of factors, such as pH, contact time, temperature, dosage, and salt concentration, were investigated. The results revealed that the addition of modified sawdust can significantly increase the adsorption capacity of dye. The maximum adsorption capacity of dye on modified sawdust was 109 mg·g-1 at 328K. The adsorption processes were rapid within the first 30 min and reached equilibrium in about 150 min. The adsorption kinetics fitted well with pseudo-second-order model. The pH value of the solution had significant impact on the amount of adsorption. Adsorption isotherm fitted better with the Langmuir model and the adsorption was an endothermic process


Author(s):  
Shailesh R. Sheth ◽  
Jayesh R. Bellare

Specimen support and astigmatism correction in Electron Microscopy are at least two areas in which lacey polymer films find extensive applications. Although their preparation has been studied for a very long time, present techniques still suffer from incomplete release of the film from its substrate and presence of a large number of pseudo holes in the film. Our method ensures complete removal of the entire lacey film from the substrate and fewer pseudo holes by pre-treating the substrate with Gum Arabic, which acts as a film release agent.The method is based on the classical condensation technique for preparing lacey films which is essentially deposition of minute water or ice droplets on the substrate and laying the polymer film over it, so that micro holes are formed corresponding to the droplets. A microscope glass slide (the substrate) is immersed in 2.0% (w/v) aq. CTAB (cetyl trimethyl ammonium bromide)-0.22% (w/v) aq.


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