scholarly journals Zeolites as alcohol adsorbents from aqueous solutions

2006 ◽  
pp. 83-87 ◽  
Author(s):  
Blagica Cekova ◽  
Dragi Kocev ◽  
Elena Kolcakovska ◽  
Daniela Stojanova

The potential usage of zeolites as adsorbents for the removal of organic molecules from water was investigated in a series of experiments with aqueous solutions of lower alcohols. This could represent a simple solution to the problem of cleaning up industrial wastewater as well as recovering valuable chemicals at relatively low costs. Adsorption isotherms of the Langmuir type were applied, and calculations showed that the amount of propanol adsorbed on silicalite corresponded to approximately 70% of the pore volume. The adsorption process is simple, and recovery of the more concentrated products is easily done by heat treatment and/or at lowered pressures. Adsorption experiments with aqueous acetone showed that silicalite had approximately the same adsorption capacity for acetone as for n-propanol. Heats of adsorption were determined calorimetrically.

Proceedings ◽  
2019 ◽  
Vol 16 (1) ◽  
pp. 56
Author(s):  
Jędrys-Wolska ◽  
Korus

Colored industrial wastewater is a threat in many environmental aspects. As such, there is a need to find more effective methods for its purification. This article presents a brief overview of available methods for removing dyes from aqueous solutions, among them the adsorption process, which is the subject of this study. The course of preliminary tests on the process of cleaning dye solutions in the adsorption process is presented. Unmodified magnetite and magnetite modified with polymers were used as adsorbents. The synthesis of particular types of magnetite, the adsorption process, as well as the methods of further analyzes are described. As part of the work, the focus was put on a comparison of the effectiveness of the purification process for different types of adsorbents in relation to selected dyes. The varied conditions of the process were also analyzed. It has been shown that magnetite is an adsorbent that is easy to use, allowing effective separation of dyes of various chemical structures from aqueous solutions. The effectiveness of the process depends on the type of dye and on the pH value and can be increased in relation to some dyes by using magnetite modification with selected polymers.


2019 ◽  
Vol 79 (10) ◽  
pp. 1922-1933 ◽  
Author(s):  
Hee-Jeong Choi

Abstract Hybrid adsorbents (ES) were prepared with mixing of eggshell and sericite as binders, and Pb(II) was removed from aqueous solutions. Sericite has the advantage of not only serving as a binder for hybrid adsorbent but also having a negative charge on the surface to improve the removal efficiency of heavy metals. Various parameters affecting the removal of Pb(II) from aqueous solutions were investigated using the optimal conditions derived. In addition, adsorption kinetics, adsorption isotherms and thermodynamic analyses were performed using the experimental results of each parameter. The ES had a more specific surface area and porosity than sericite or eggshell and contained a large number of OH groups favoring heavy metal adsorption. As a result of the adsorption of Pb(II) using the ES, the adsorption process was physical and suitable for the Freundlich isotherm. In addition, the adsorption process of Pb(II) by the ES was a spontaneous endothermic reaction. The ES can quickly reach the adsorption equilibrium and strong adsorption strength. In addition, the CaOH contained in the ES can neutralize the pH of wastewater, and it is possible to treat heavy metal ions in industrial wastewater and acid mine wastewater without controlling the pH. ES adsorbents using waste eggshells are very economic because they recycle what would otherwise be waste and have great significance in terms of resource reuse.


2017 ◽  
Vol 68 (3) ◽  
pp. 483-486
Author(s):  
Constantin Sorin Ion ◽  
Mihaela Bombos ◽  
Gabriel Vasilievici ◽  
Dorin Bombos

Desulfurisation of atmospheric distillation gasoline and gas oil was performed by adsorption process on Fe/ bentonite. The adsorbent was characterized by determining the adsorption isotherms, specific surface area, pore volume and average pore diameter. Adsorption experiments of atmospheric distillation gasoline and gas oil were performed in continuous system at 280�320oC, 5 atm and volume hourly space velocities of 1�2 h-1. The efficiency of adsorption on Fe / bentonite was better at desulphurisation of gasoline versus gas oil.


2018 ◽  
Vol 69 (5) ◽  
pp. 1233-1239
Author(s):  
Raluca Madalina Senin ◽  
Ion Ion ◽  
Ovidiu Oprea ◽  
Rusandica Stoica ◽  
Rodica Ganea ◽  
...  

In this study, non-irradiated and weathered multiwalled carbon nanotubes (MWCNTs) obtained through irradiation, were studied as adsorbents for BPA, both nanomaterials being characterized before and after the adsorption process. The objectives of our investigation were to compare the characteristics of non-irradiated and irradiated MWCNTs, to evaluate the adsorption capacity of BPA by pristine and irradiated MWCNTs and to determine the variation of the kinetic, sorption and thermodynamic parameters during sorption process using both sorbents.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3655
Author(s):  
Daniele C. da Silva Alves ◽  
Bronach Healy ◽  
Tian Yu ◽  
Carmel B. Breslin

Graphene and its derivatives, especially graphene oxide (GO), are attracting considerable interest in the fabrication of new adsorbents that have the potential to remove various pollutants that have escaped into the aquatic environment. Herein, the development of GO/chitosan (GO/CS) composites as adsorbent materials is described and reviewed. This combination is interesting as the addition of graphene to chitosan enhances its mechanical properties, while the chitosan hydrogel serves as an immobilization matrix for graphene. Following a brief description of both graphene and chitosan as independent adsorbent materials, the emerging GO/CS composites are introduced. The additional materials that have been added to the GO/CS composites, including magnetic iron oxides, chelating agents, cyclodextrins, additional adsorbents and polymeric blends, are then described and discussed. The performance of these materials in the removal of heavy metal ions, dyes and other organic molecules are discussed followed by the introduction of strategies employed in the regeneration of the GO/CS adsorbents. It is clear that, while some challenges exist, including cost, regeneration and selectivity in the adsorption process, the GO/CS composites are emerging as promising adsorbent materials.


2021 ◽  
Author(s):  
Liang Wang ◽  
Peng Gao ◽  
Mengxin Liu ◽  
Ziqing Huang ◽  
Shixia Lan ◽  
...  

Monodisperse polypyrrole/SBA-15 composite (PPy/SBA-15) was fabricated by in-situ polymerization and used for Cr(Ⅵ) adsorption from aqueous solution. PPy/SBA-15 was characterized by numerous approaches. Factors affecting the Cr(Ⅵ) adsorption process included...


2017 ◽  
Vol 76 (8) ◽  
pp. 2242-2253 ◽  
Author(s):  
Z. Yavari ◽  
M. Noroozifar

In this study, black carbon from pine cone (BCPC) and acidic-modified BCPC (MBCPC) powder as a popular agricultural waste in the southeast of Iran were used for cadmium removal from aqueous solutions. The effect of various factors, such as surface chemistry and dosage of adsorbent, contact time, size of particles, initial concentration of cadmium, temperature, and pH of aqueous solutions, was investigated. The results show cadmium removal with usage of the mentioned adsorbents increased after acidic modification. It was noteworthy in this work that the removal percentage of pollutant was above 90% for suggested biosorbents. The obtained experimental data for optimum conditions were selected to model the adsorption behavior of the materials with usage of six isotherm equations via non-linear fitting method and the residual root mean square error estimation for each model. The adsorption of cadmium preferably fitted Khan and Langmuir–Freundlich isotherms for BCPC and MBCPC adsorbents, respectively. The kinetic studies via linear fitting method proved the second-order kinetic was the applicable model for the adsorption process. Thermodynamic studies show the adsorption process of cadmium onto BCPC and MBCPC was spontaneous and endothermic.


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.


Author(s):  
Suiyi Zhu ◽  
Xia Yang ◽  
Gu-Ning Wang ◽  
Lei-Lei Zhang ◽  
He-Feng Zhu ◽  
...  

A kind of P-25 TiO2 films coated nickel foam was synthesized by a facile dip-coating/calcination route, and used to fabricate a continuous-flow three-phase photocatalytic reactor. The morphology, crystal phase structure, surface composition and specific surface area of P-25 films coated nickel foam were investigated by field emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption measurements, respectively. The results indicated that the coated/ calcined P-25 films had the porous surface structure fabricated by nano-sized titanium dioxide consisted of two crystal phases and incorporated with a NiO interlayer. The increase of P-25 contents enhanced the specific surface area; however, 20 percent of initial P-25 sol would result in visible large cracks because of too high P-25 content and consequently cause the peeling of films. The photocatalytic activities of nickel foam with different coating amounts of P-25 for the degradation of quinoline aqueous solutions were investigated with a continuous-flow three-phase photocatalytic reactor based on the P-25 films coated nickel foam. The results suggested that nickel foam coated with 10 percent of P-25 sol had an optimal photocatalytic activity for the degradation of quinoline aqueous solutions. The continuous-flow three-phase photocatalytic reactor fabricated with P-25 films coated nickel foam with an optimal P-25 coating amount shows high photocatalytic activity and stability for the degradation of quinoline aqueous solutions and industrial wastewater. The treated industrial wastewater meets the international discharge standard.


2015 ◽  
Vol 12 (1) ◽  
pp. 148-156
Author(s):  
Baghdad Science Journal

The subject of this research involves studying adsorption to removal herbicide Atlantis WG from aqueous solutions by bentonite clay. The equilibrium concentration have been determined spectra photometry by using UV-Vis spectrophotometer. The experimental equilibrium sorption data were analyzed by two widely, Langmuir and Freundlish isotherm models. The Langmuir model gave a better fit than Freundlich model The adsorption amount of (Atlantis WG) increased when the temperature and pH decreased. The thermodynamic parameters like ?G, ?H, and ?S have been calculated from the effect of temperature on adsorption process, is exothermic. The kinetic of adsorption process was studied depending on Lagergren ,Morris ? Weber and Rauschenberg equations.


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