scholarly journals Graphene-Based Materials Immobilized within Chitosan: Applications as Adsorbents for the Removal of Aquatic Pollutants

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3655
Author(s):  
Daniele C. da Silva Alves ◽  
Bronach Healy ◽  
Tian Yu ◽  
Carmel B. Breslin
Keyword(s):  
Mechanical Properties ◽  
Heavy Metal Ions ◽  
Chelating Agents ◽  
Organic Molecules ◽  
Adsorption Process ◽  
Chitosan Hydrogel ◽  
Polymeric Blends ◽  
Aquatic Pollutants ◽  
Immobilization Matrix ◽  
Adsorbent Materials

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.

scholarly journals Adsorption process and mechanism of heavy metal ions by different components of cells, using yeast (Pichia pastoris) and Cu2+ as biosorption models

RSC Advances ◽  
2021 ◽  
Vol 11 (28) ◽  
pp. 17080-17091
Author(s):  
Xinggang Chen ◽  
Zhuang Tian ◽  
Haina Cheng ◽  
Gang Xu ◽  
Hongbo Zhou
Keyword(s):  
Heavy Metal ◽  
Pichia Pastoris ◽  
Metal Ions ◽  
Cell Walls ◽  
Heavy Metal Ions ◽  
Adsorption Process ◽  
Yeast Pichia Pastoris ◽  
Adsorption Sites

The Cu2+ first bound to the outer mannan and finally entered the cytoplasm. During the whole adsorption process, the number of adsorption sites in the outer and middle cell walls was the largest, and then gradually decreased.

scholarly journals An Investigation into the Adsorption of Aniline from Aqueous Solution Using H-Beta Zeolites and Copper-Exchanged Beta Zeolites

2005 ◽  
Vol 23 (3) ◽  
pp. 255-266 ◽  
Author(s):  
J. O'Brien ◽  
T. Curtin ◽  
T.F. O'Dwyer
Keyword(s):  
Aqueous Solution ◽  
Adsorption Process ◽  
Zeolite Beta ◽  
Langmuir Model ◽  
Beta Zeolite ◽  
Copper Leaching ◽  
Beta Zeolites ◽  
The Stability ◽  
Ph Range ◽  
Adsorbent Materials

Zeolite beta, a large-pore zeolite, was investigated in this study with a view to examining it as a potential adsorbent for the removal of aniline from aqueous solutions. Two different metal-loaded zeolites were prepared by exchanging H-beta zeolite (SiO2/Al2O3 = 75:1) with copper. The influence of exchanged copper on the uptake level was assessed. The effect of varying the silica-to-alumina ratio of the H-beta zeolite on the aniline uptake level was also examined, using three different H-beta zeolites with ratios of 25:1, 75:1 and 150:1 as adsorbents. The sorption experiments indicated an uptake level of ca. 110–120 mg/g for each zeolite and this level was also adsorbed by the copper-modified H-beta zeolites (SiO2/Al2O3 = 75:1). In all cases, the adsorption process followed the Langmuir model for adsorption and the level of aniline adsorbed was largely unaffected by a change in temperature or the presence of extra framework copper. The stability of the exchanged copper on these zeolites was then examined by measuring the quantity of copper leached from each zeolite into solution as a function of pH. Minimum copper leaching was observed in the pH range 5–11. This provided a stable pH working range for the adsorbent materials.

scholarly journals Zeolites as alcohol adsorbents from aqueous solutions

2006 ◽  
pp. 83-87 ◽  
Author(s):  
Blagica Cekova ◽  
Dragi Kocev ◽  
Elena Kolcakovska ◽  
Daniela Stojanova
Keyword(s):  
Heat Treatment ◽  
Aqueous Solutions ◽  
Pore Volume ◽  
Industrial Wastewater ◽  
Organic Molecules ◽  
Adsorption Process ◽  
Aqueous Acetone ◽  
Heats Of Adsorption ◽  
Series Of Experiments ◽  
Low Costs

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.

scholarly journals Eco-Friendly Sustainable Fluorescent Carbon Dots for the Adsorption of Heavy Metal Ions in Aqueous Environment

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 315 ◽  
Author(s):  
Musa Yahaya Pudza ◽  
Zurina Zainal Abidin ◽  
Suraya Abdul Rashid ◽  
Faizah Md Yasin ◽  
A. S. M. Noor ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Carbon Dots ◽  
Heavy Metal Ions ◽  
Active Sites ◽  
Adsorption Process ◽  
Coefficient Of Determination ◽  
Aqueous Environment ◽  
Order Kinetic ◽  
Sensing Applications

The materials and substances required for sustainable water treatment by adsorption technique, are still being researched widely by distinguished classes of researchers. Thus, the need to synthesize substances that can effectively clean up pollutants from the environment cannot be overemphasized. So far, materials in bulk forms that are rich in carbon, such as biochar and varieties of activated carbon have been used for various adsorptive purposes. The use of bulk materials for such purposes are not efficient due to minimal surface areas available for adsorption. This study explores the adsorption task at nano dimension using carbon dots (CDs) from tapioca. The properties of carbon structure and its influence on the adsorptive efficacy of carbon nanoparticles were investigated by energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HrTEM), and atomic force microscopy (AFM). The results implied carbon present in CDs are good adsorbents for effective adsorption of heavy metal ions (lead) with removal efficiency of 80.6% in aqueous environment. The adsorption process as explored by both Langmuir and Freundlich isotherms have proven favorability of the adsorption process. Langmuir form two and three have correlation coefficients R2 at 0.9922 and 0.9912, respectively. The Freundlich isotherm confirms CDs as having defined surface heterogeneity and the exponential distribution of active sites. The adsorption of lead unto CDs obeyed the second order kinetic model with coefficient of determination, R2 of 0.9668 and 0.9996 at an initial lead concentration of 20 mg/L and 100 mg/L, respectively. The findings validated the efficiency of CDs derived from tapioca as an excellent material for further utilization in the environmental fields of wastewater pollution detection and clean up, bio-imaging, and chemical sensing applications.

Grain Refining Behavior of Zr, Al2Y and Al4C3 Particles in Magnesium Alloys by the First-Principles Calculations

2015 ◽  
Vol 816 ◽  
pp. 370-374
Author(s):  
Jun Ling Pan ◽  
Qiu Ming Peng ◽  
Jian Xin Guo ◽  
Hui Li
Keyword(s):  
Mechanical Properties ◽  
Structural Optimization ◽  
Magnesium Alloys ◽  
Density Of States ◽  
Adsorption Energy ◽  
First Principles ◽  
Adsorption Process ◽  
Mg Alloys ◽  
Grain Refining ◽  
First Principles Calculations

Grain refining is one of the most important issues in the applications of Mg alloys, which directly determines mechanical properties and deformability. Therefore the understanding of grain refining mechanism during solidification will be benefit to develop new grain refiners. Herein refining role was elucidated by the first principles calculations based on adsorption behavior of a Mg atom on the closest-packed planes of grain refiners (Zr (001), Al2Y(311) and Al4C3(102)). Taking into account different sites, the site with the maximum adsorption energy value generally corresponded to the most possible location. The adsorption energy results show that the possible refining turn follows Al4C3(102)>Zr (001)>Al2Y(311). Meanwhile, the structural optimization confirmed that the Mg atom connected with two C atoms on the top of zig-zag plane of Al4C3(102), three Zr atoms at the hcp position on Zr (001), and two Y atoms and one Al atom at the bottom of zig-zag plane of Al2Y(311). The density of states revealed that the variation of d-orbital electrons of Mg atom became apparent during adsorption process. The values of Mulliken charges were 0.898 e in Al4C3(102), 0.410 e in Zr (001) and 0.245 e in Al2Y(311), respectively. This tendency agrees well with the previous experimental results. It indicates the adsorption energy on the closest-packed planes can be regarded as a prerequisite to select new grain refiners for Mg alloys in future.

scholarly journals The Interaction of Air Pollutant Molecules with Germanene and Silicene: a Density Functional Theory Study

Molekul ◽  
2018 ◽  
Vol 13 (1) ◽  
pp. 92
Author(s):  
Muhammad Rifqi Al Fauzan ◽  
Wijayanti Dwi Astuti ◽  
Ghorby Al Fauzan ◽  
Sholihun Sholihun
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Adsorption Process ◽  
Air Pollutant ◽  
Atmospheric Pollutants ◽  
Mulliken Charge ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Calculation Results ◽  
Adsorbent Materials

We investigate the adsorption of atmospheric pollutants on germanene and silicene using density functional theory (DFT) calculations. In this study, we use carbon monoxide (CO) and nitric oxide (NO) as the pollutant molecules. Electronic properties of germanene and silicene are explored to obtain a good understanding in the adsorption process. Our calculation results show both germanene and silicene provide an identical mechanism of adsorption. Germanene and silicene adsorb CO and NO spontaneously with physisorption and chemisorption types for CO and NO molecules, respectively. We also conduct the Mulliken charges calculations to evaluate the transformation of atomic charges due to the adsorption process. From Mulliken charge calculation results we can confirm the existence of charge transfer between the adsorbent materials and the pollutant molecules. This phenomenon lies behind the occurrence of the adsorption process.

scholarly journals Preparation of Xylan-g-/P(AA-co-AM)/GO Nanocomposite Hydrogel and its Adsorption for Heavy Metal Ions

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 621 ◽  
Author(s):  
Weiqing Kong ◽  
Minmin Chang ◽  
Chunhui Zhang ◽  
Xinxin Liu ◽  
Bei He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Adsorption Capacity ◽  
Heavy Metal Ions ◽  
Raw Materials ◽  
Ammonium Persulfate ◽  
Maximum Adsorption Capacity ◽  
Nanocomposite Hydrogel ◽  
X Ray ◽  
Nanocomposite Hydrogels

Xylan-g-/P(AA-co-AM)/Graphene oxide (GO) hydrogels were prepared and used in the removal of heavy mental ions. Acrylamide (AM), acrylic acid (AA), and xylan were used as the raw materials to prepare the hydrogels with ammonium persulfate (APS) as the initiator. The prepared hydrogels were characterized by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and energy dispersive X-ray (EDX). Some important properties of nanocomposite hydrogels such as swelling behavior, mechanical property, and adsorption capacity were also examined as well as the regeneration of the hydrogels. The results showed that the prepared hydrogels reached the equilibrium state of swelling after 12 h, and the compressive strength of the hydrogel with 30 mg of GO could reach up to 203 kPa. Compared with traditional hydrogel, the mechanical properties of the hydrogels with GO were obviously improved. The maximum adsorption capacity of hydrogels for Pb2+, Cd2+, and Zn2+ could reach up to 683 mg/g, 281 mg/g, and 135 mg/g, respectively. After five cycles of adsorption and desorption, the recovery rate of the hydrogels on Pb2+, Cd2+, and Zn2+ was still up to 87%, 80%, and 80%, respectively—all above 80%.

scholarly journals Different Insights into Silicate Rectorite Modification and Its Role in Removal of Heavy Metal Ions from Wastewater

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 176 ◽  
Author(s):  
Ya Gao ◽  
Hao Jiang ◽  
Xianyuan Li ◽  
Sultan Ahmed Khoso ◽  
Guoyuan Xiang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Adsorption Process ◽  
Underlying Mechanism ◽  
Xps Analysis ◽  
Adsorption Efficiency ◽  
Removal Capacity ◽  
Chloride Hexahydrate ◽  
Ferric Chloride Hexahydrate

In the field of water management, the separation of metal contaminants from wastewater is very important and challenging. This study systematically investigated the effect and underlying mechanism of silicate rectorite (REC) on the removal of heavy metal ions (Cr(VI) and Pb(II)) from wastewater. The adsorption and removal capacity of REC was further improved by its novel modification with ferric chloride hexahydrate. Compared to natural REC, the modified rectorite (Fe-REC) showed comparatively superior adsorption efficiency for both Cr(VI) and Pb(II) due to the chemisorption of Fe3+ on the REC surface as its oxidation state (Fe–O, Fe–OH, Fe–OOH). Adsorption on Cr(VI) attributed to the reaction between iron hydroxy complexes (FeOH2+, Fe(OH)2+ and Fe(OH)3(aq)) and Cr(VI) species (HCrO4− and CrO42−) in the aqueous solution. This reaction was perfectly consistent with the binding energy shifts in O 1s and Fe 2p species, as reflected by XPS analysis. While, the existence of –Al–OH and –Si–OH in silicate REC slurry reacted with PbOH+ colloids produced from lead ions hydrolysis to promote Pb(II) adsorption. Zeta potential after modification and removal occurred to shift positively or negatively to testify the adsorption of Fe3+ and heavy metal ions. Freundlich and Langmuir isotherms conformed adsorption process for Cr(VI) and Pb(II), respectively.

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