Adsorption, desorption and oxidation of arsenic affected by clay minerals and aging process

2000 ◽  
Vol 39 (7) ◽  
pp. 753-759 ◽  
Author(s):  
Z. Lin ◽  
R. W. Puls
Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1282
Author(s):  
Jorge Cesar Masini ◽  
Gilberto Abate

Natural and modified clay minerals have been extensively used for the adsorption/desorption of organic substances, especially pesticides, from waters and wastewater, aiming at pollution control and more efficient use of the herbicides through controlled release. While natural clay minerals efficiently remove organic cations such as paraquat and diquat, the adsorption of anionic or neutral species demands surface chemical modification with, for instance, quaternary ammonium salts containing long alkyl chains. Basic pesticides, on the other hand, are better absorbed in clay minerals modified with polycations. Kinetic studies and adsorption/desorption isotherms provide the parameters needed to evaluate the clay mineral’s adsorptive performance towards the pollutant target. However, the direct comparison of these parameters is complicated because the experimental conditions, the analytical techniques, the kinetic and isotherm models, and the numerical fitting method differ among the various studies. The free-energy-related Langmuir constant depends on the degree of site occupation; that is, it depends on the concentration window used to construct the adsorption isotherm and, consequently, on the analytical technique used to quantify the free concentrations. This paper reviews pesticides’ adsorption on natural and modified clay minerals and proposes guidelines for designing batch adsorption/desorption studies to obtain easily comparable and meaningful adsorption parameters. Articles should clearly describe the experimental conditions such as temperature, contact time, total concentration window, the solution to adsorbent ratio, the analytical technique, and its detection and quantification limits, besides the fitting models. Research should also evaluate the competitive effects of humic substances, colloidal inorganic particles, and ionic strength to emulate real-world adsorption experiments.


2019 ◽  
Vol 3 (1) ◽  
pp. 41 ◽  
Author(s):  
Victoria Tobilko ◽  
Larysa Spasonova ◽  
Iryna Kovalchuk ◽  
Borys Kornilovych ◽  
Yurij Kholodko

Silylation of clay minerals from Cherkasy deposit (Ukraine) montmorillonite (layer silicate) and palygorskite (fibrous silicate) was performed using organosilane (3-aminopropyl)triethoxysilane (APTES). Solvents with different polarity (ethanol, toluene) were used in synthesis. The structure of modified minerals was characterized by complex of methods (X-ray powder diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption-desorption at −196 °C and thermal analysis). Studies of adsorption characteristics of APTES-modified clay minerals were carried out in relation to uranium (VI). The results indicated that modified montmorillonite and palygorskite were effective materials for water purification from UO22+.


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Hiroki Mukai ◽  
Atsushi Hirose ◽  
Satoko Motai ◽  
Ryosuke Kikuchi ◽  
Keitaro Tanoi ◽  
...  

Chemosphere ◽  
1994 ◽  
Vol 28 (3) ◽  
pp. 627-638 ◽  
Author(s):  
Yuncong Li ◽  
Gian Gupta

1997 ◽  
Vol 186 (2) ◽  
pp. 234-247 ◽  
Author(s):  
F. Blockhaus ◽  
J.-M. Séquaris ◽  
H.D. Narres ◽  
M.J. Schwuger

2018 ◽  
Vol 15 (2) ◽  
pp. 292-297
Author(s):  
Is Fatimah ◽  
Dwiarso Rubiyanto ◽  
Septian Perwira Yudha ◽  
Gunarti Pratiwi ◽  
Ayu Puspita

Purpose The purpose of this study is to prepare composite of chitosan-modified smectite clays consisting of montmorillonite and saponite clay minerals and their urea adsorption–desorption study. Prepared materials were designed for slow-release fertilizer application. Design/methodology/approach Preparation of the composites was conducted by a simple intercalation of chitosan solution and clay suspension followed by hydrogel beads formation. Physicochemical characterization of materials was performed by X-ray diffraction, gas sorption analysis by using Brunauer–Emmett–Teller surface areas and pore volume, water absorbency and Fourier transform-infrared. Urea adsorption and desorption studies of prepared materials were conducted by using batch method, and the adsorbed and desorbed urea content was analyzed by using high-performance liquid chromatography method. Findings The results revealed that the composites have higher absorptivity and lower absorptivity toward urea from and into water solution compared to raw clay minerals. Adsorption capacity and slow desorption rate of urea from the composites suggested the potential application of the composites as slow urea-releasing agent. Originality/value There are many papers that study the formation of chitosan-clay composites, but the study on the urea adsorption–desorption properties based on chitosan-smectite minerals have not been reported. Intensive study related to physicochemical properties and its related kinetics study is an important basic finding for further applications.


2017 ◽  
Vol 56 ◽  
pp. 180-191 ◽  
Author(s):  
Mahdi Safaei Khorram ◽  
Dunli Lin ◽  
Qian Zhang ◽  
Yuan Zheng ◽  
Hua Fang ◽  
...  

2004 ◽  
Vol 84 (1-3) ◽  
pp. 133-141 ◽  
Author(s):  
M. Soledad Andrades ◽  
M. Sonia Rodríguez-Cruz ◽  
M. Jesús Sánchez-Martín ◽  
Maria Sánchez-Camazano

1994 ◽  
Vol 3 (2) ◽  
pp. 127-135 ◽  
Author(s):  
Yuncong Li ◽  
Gian Gupta

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