scholarly journals Natural clays as effective sorbents of anthropogenic pollutants

2021 ◽  
Vol 885 (1) ◽  
pp. 012060
Author(s):  
S V Badmaeva ◽  
S Ts Khankhasaeva ◽  
M V Ukhinova
Keyword(s):  
Aqueous Media ◽  
Dye Adsorption ◽  
Methyl Green ◽  
Anthropogenic Pollutants ◽  
Pseudo Second Order ◽  
Natural Clays ◽  
Kinetics Of ◽  
Adsorptive Properties ◽  
Effective Sorbent ◽  
Good Agreement

Abstract In this work, the adsorptive properties the Tuldon deposit were studied using the example of the adsorption of the basic dye “Methyl Green” from aqueous solutions. It has been established that the kinetic regularities of the dye adsorption on clay are consistent with the model of the kinetics of the pseudo-second order, characteristic of chemisorption. The isotherm of the dye adsorption is in good agreement with the Langmuir model. The results of the study allow us to conclude that the clay of the Tuldon deposit can be an effective sorbent for removing basic dyes from aqueous media.

scholarly journals Interactions of Cd2+, Co2+ and MoO42− Ions with Crushed Concrete Fines

2021 ◽  
Vol 5 (2) ◽  
pp. 42
Author(s):  
Victoria K. Elmes ◽  
Nichola J. Coleman
Keyword(s):  
Contaminated Soils ◽  
Aqueous Media ◽  
Fine Fraction ◽  
Freundlich Isotherm ◽  
Crushed Concrete ◽  
Pseudo Second Order ◽  
Zero Order Reaction ◽  
Co Precipitation ◽  
Material Accounting ◽  
Effective Sorbent

Construction and demolition activities generate approximately two thirds of the world’s waste, with concrete-based demolition material accounting for the largest proportion. Primary aggregates are recovered and reused, although the cement-rich fine fraction is underutilised. In this study, single metal batch sorption experiments confirmed that crushed concrete fines (CCF) are an effective sorbent for the maximum exclusion of 45.2 mg g−1 Cd2+, 38.4 mg g−1 Co2+ and 56.0 mg g−1 MoO42− ions from aqueous media. The principal mechanisms of sorption were determined, by scanning electron microscopy of the metal-laden CCF, to be co-precipitation with Ca2+ ions released from the cement to form solubility limiting phases. The removal of Co2+ and MoO42− ions followed a zero-order reaction and that of Cd2+ was best described by a pseudo-second-order model. The Langmuir model provided the most appropriate description of the steady state immobilisation of Cd2+ and Co2+, whereas the removal of MoO42− conformed to the Freundlich isotherm. Long equilibration times (>120 h), loose floc formation and high pH are likely to limit the use of CCF in many conventional wastewater treatment applications; although, these properties could be usefully exploited in reactive barriers for the management of contaminated soils, sediments and groundwater.

Mechanism of bromination of a quaternary pyrimidinium cation. Change of rate determining step with acidity

1978 ◽  
Vol 56 (23) ◽  
pp. 2970-2976 ◽  
Author(s):  
Oswald S. Tee ◽  
David C. Thackray ◽  
Charles G. Berks
Keyword(s):  
Kinetic Study ◽  
Rate Constants ◽  
Aqueous Media ◽  
Stopped Flow ◽  
Flow Method ◽  
High Acidity ◽  
Rate Determining Step ◽  
Kinetics Of ◽  
Good Agreement

The kinetics of bromination of the 1,2-dihydro-1,3-dimethyl-2-oxopyrimidinium cation (Q+) in aqueous media (pH 0–5) have been studied using the stopped-flow method. At the higher acidities (pH < 2) the results are consistent with rate determining attack by bromine upon the pseudobase (QOH), whereas at low acidities (pH > 4) it appears that pseudobase formation is rate determining. The change occurs because at high acidity the reversal of the pseudobase QOH to the cation is fast relative to bromine attack, whereas at low acidity the converse is true. Results obtained at intermediate acidities (pH 2–4) are consistent with this interpretation.A separate kinetic study of pseudobase formation (and decomposition) yielded rate constants in good agreement with those derived from the bromination study.

Application of the intra-particle diffusion model for activated carbon fibers in an aqueous medium

2012 ◽  
Vol 1373 ◽  
Author(s):  
Teresa Ramírez-Rodríguez ◽  
Fray de Landa Castillo-Alvarado
Keyword(s):  
Activated Carbon ◽  
Diffusion Model ◽  
Carbon Fibers ◽  
Aqueous Media ◽  
Particle Diffusion ◽  
Activated Carbon Fibers ◽  
Kinetics Of Adsorption ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order ◽  
Kinetics Of

ABSTRACTThe intra-particle diffusion model (IPD), proposed by Weber and Morris has been applied to the analysis of the kinetics of adsorption on activated carbon fibers with phosphate groups in the removal of cadmium ions in aqueous media. It is evident that the removal of cadmium ion kinetic model of pseudo-second order provides a better fit than the model of pseudo-first order and the intra-particle diffusion model provides the best to the sample compared activating solution: grams fibers of 1:3.

Study of the Dye Adsorption Kinetics of Metal–Organic Frameworks in Aqueous Media

2020 ◽  
Vol 41 (8) ◽  
pp. 843-850 ◽  
Author(s):  
Sungjune Kim ◽  
Jihyun Lee ◽  
Younghu Son ◽  
Minyoung Yoon
Keyword(s):  
Adsorption Kinetics ◽  
Metal Organic Frameworks ◽  
Aqueous Media ◽  
Dye Adsorption ◽  
Metal Organic ◽  
Kinetics Of

Native, acidic pre-treated and composite clay efficiency for the adsorption of dicationic dye in aqueous medium

2016 ◽  
Vol 75 (4) ◽  
pp. 753-764 ◽  
Author(s):  
Asma Ehsan ◽  
Haq Nawaz Bhatti ◽  
Munawar Iqbal ◽  
Saima Noreen
Keyword(s):  
Contact Time ◽  
Dye Adsorption ◽  
Industrial Effluents ◽  
Methyl Green ◽  
Order Kinetic ◽  
Adsorption Efficiency ◽  
Adsorption Behaviors ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Adsorbent Dose

Environmental applications of composites have attracted the interests of researchers due to their excellent adsorption efficiency for pollutants. Native, HCl pre-treated clay and MnFe2O4/clay composite were investigated as an adsorbent for removal of methyl green from aqueous solution. The adsorption behaviors of dye onto native, HCl pre-treated and composite clays were studied as a function of contact time, adsorbent dose, pH, initial dye concentration and temperature. Maximum dye adsorption of 44 mg/g was achieved at pH of 8, contact time 40 min, adsorbent dose 0.20 g/L and initial dye concentration of 125 mg/L using clay composite. The Langmuir isotherm and pseudo-second-order kinetic model best explained the methyl green dye adsorption onto clay adsorbents. Thermodynamic parameters revealed the endothermic and spontaneous adsorption nature of dye. From results, it is concluded that clay has potential for adsorbing methyl green and can be used for the removal of dyes from industrial effluents.

scholarly journals Adsorption of Thymol onto Natural Clays of Morocco: Kinetic and Isotherm Studies

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Hamid Ziyat ◽  
Mohammed Naciri Bennani ◽  
Hassan Hajjaj ◽  
Omar Qabaqous ◽  
Said Arhzaf ◽  
...  
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
X Ray Diffraction ◽  
Order Model ◽  
Freundlich Model ◽  
Kinetics Of Adsorption ◽  
Adsorption Capacities ◽  
Pseudo Second Order ◽  
Natural Clays ◽  
Uv Visible ◽  
Kinetics Of

The present work aims to study the affinity of a component of the thyme essential oil “thymol” to natural Moroccan clay “Rhassoul” using the adsorption technique. The physicochemical characterizations of the purified and modified clay were carried out by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), DTA/TGA, and SEM-EDX. Thymol adsorption tests on the purified Rhassoul (Rh-P) and the modified one by CTAB (Rh-CTAB) were followed by UV-visible spectroscopy. They show that the adsorption isotherms can be described by the Freundlich model and that the kinetics of adsorption is in accordance with the pseudo-second-order model for the two clays. Adsorption capacities obtained were of the order of 6 mg/g for the purified Rhassoul and 16 mg/g for the modified Rhassoul by cetyltrimethylammonium bromide (CTAB). These values show that the modified Rhassoul has a better adsorption capacity compared to the purified Rhassoul.

Sorption of thallium(I) ions by peat

2013 ◽  
Vol 68 (10) ◽  
pp. 2208-2213 ◽  
Author(s):  
Artis Robalds ◽  
Maris Klavins ◽  
Liga Dreijalte
Keyword(s):  
Sorption Capacity ◽  
Batch Mode ◽  
Maximum Sorption Capacity ◽  
Maximum Sorption ◽  
Pseudo Second Order ◽  
Copper Zinc ◽  
Industrial Use ◽  
Kinetics Of ◽  
Kinetics Of Sorption ◽  
Effective Sorbent

The increasing industrial use of thallium has raised the need for removal of this highly toxic element from wastewater. Thallium is more toxic than cadmium, copper, zinc, lead and mercury and as it is easily accumulated in humans, animals and plants, it poses a threat to both the environment and human health. Peat has been used as an effective, relatively cheap and easily available sorbent to treat waters containing heavy metals. In this study, peat was characterized and used as sorbent for the removal of Tl(I) ions from aqueous solution. The effect of initial Tl(I) concentration, pH, contact time, temperature and ionic strength was studied in batch mode. The maximum sorption capacity of peat reached 24.14 mg/g at 20 °C and initial Tl(I) concentration of 500 mg/L. Sorption capacity was found to be pH dependent and maximum uptake occurred at pH 10. Kinetic data revealed that sorption was relatively rapid – 82.8% of Tl(I) ions were sorbed in the first 10 min. The kinetics of sorption was analyzed using pseudo-first order and pseudo-second order models. Results show that peat can be used as an effective sorbent to remove Tl(I) ions from aqueous solutions.

scholarly journals Use of Garlic Processing By-Products to Remove Pollutants from Aqueous Media

2021 ◽  
Vol 12 (4) ◽  
pp. 4518-4528
Keyword(s):  
Activated Carbons ◽  
Aqueous Media ◽  
Order Model ◽  
Chemical Reagents ◽  
Adsorption Processes ◽  
Pseudo Second Order ◽  
Sorption Parameters ◽  
Kinetics Of ◽  
By Products ◽  
Sorption Characteristics

The paper summarized the literature data on using ground peels, outer leaves, and garlic roots (Allium sativum L.) as sorption materials to remove various metal ions, dyes, and antibiotics from aqueous media. This paper provides brief information on the amount of waste generated from processing garlic, its chemical composition, and ways of reuse. It gives the adsorption processes parameters and the values of sorption parameters for the studied pollutants. It was shown that garlic residue sorption characteristics for various pollutants could be increased by chemical modification with various chemical reagents. It was determined that the Langmuir model more accurately describes the pollutant’s adsorption isotherms in most cases, and the kinetics of the process more accurately describes the pseudo-second-order model. It was shown that garlic peels and steam are good precursors for activated carbons production.

Effect of Pretreatments on Wettability and Dyeing Property of Cotton Fibers in an Environmentally Friendly Dyeing System

2021 ◽  
Vol 8 (5) ◽  
pp. 1-10
Author(s):  
Wencheng Tang ◽  
Liujun Pei ◽  
Hongjuan Zhang ◽  
Lei Zhu ◽  
Jiping Wang
Keyword(s):  
Cotton Fiber ◽  
Dye Adsorption ◽  
Aqueous System ◽  
Cotton Fibers ◽  
Alkali Pretreatment ◽  
Dyeing Property ◽  
Dyeing Properties ◽  
Pseudo Second Order ◽  
Color Depth ◽  
Kinetics Of

To investigate the influence of cotton wettability on its dyeing properties in a silicone non-aqueous dyeing system, alkali pretreatment was performed before dyeing. The dyeing properties and dyeing kinetics of reactive dyes in the non-aqueous system and a conventional dyeing system were compared. Alkali pretreatment significantly improved the wettability of cotton fiber by removing wax and pectin. The adsorption rate of dye increased with increased cotton fiber wettability using the non-aqueous system, while it barely changed using the conventional system. Pseudo-second-order kinetics fit well with dye adsorption for both systems. Dye fixation improved by 30% at a concentration of 2% owf, along with better levelness and color depth of the dyed cotton fiber, using the silicone non-aqueous system without salts and dispersants.

scholarly journals Adsorption Characteristics of Bixin on Acid- and Alkali-Treated Kaolinite in Aprotic Solvents

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Winda Rahmalia ◽  
Jean-François Fabre ◽  
Thamrin Usman ◽  
Zéphirin Mouloungui
Keyword(s):  
Adsorption Capacity ◽  
Dimethyl Carbonate ◽  
Dye Adsorption ◽  
Aprotic Solvents ◽  
Band Position ◽  
Before And After ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Kinetics Of ◽  
Better Than

The adsorption of bixin in aprotic solvents onto acid- and alkali-treated kaolinite was investigated. Kaolinite was treated three times, for 6 h each, with 8 M HCl or 5 M KOH. The adsorbents were characterized by XRD, FT-IR, EDS, and BET-N2. The effects of contact time and dye concentration on adsorption capacity and kinetics, electronic transition of bixin before and after adsorption, and also mechanism of bixin-kaolinite adsorption were investigated. Dye adsorption followed pseudo-second order kinetics and was faster in acetone than in dimethyl carbonate. The best adsorption results were obtained for KOH-treated kaolinite. In both of the solvents, the adsorption isotherm followed the Langmuir model and adsorption capacity was higher in dimethyl carbonate (qm = 0.43 mg/g) than in acetone (0.29 mg/g). The adsorption capacity and kinetics of KOH-treated kaolinite (qm = 0.43 mg/g,k2 = 3.27 g/mg·min) were better than those of HCl-treated kaolinite (qm = 0.21 mg/g,k2 = 0.25 g/mg·min) and natural kaolinite (qm = 0.18 mg/g,k2 = 0.32 g/mg·min). There are shift in the band position of maximum intensity of bixin after adsorption on this adsorbent. Adsorption in this system seemed to be based essentially on chemisorption due to the electrostatic interaction of bixin with the strong basic and reducing sites of kaolinite.

Sign in / Sign up

Export Citation Format

Share Document