scholarly journals Modified Chitosan for Silver Recovery—Kinetics, Thermodynamic, and Equilibrium Studies

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 657 ◽  
Author(s):  
Bogdan Pascu ◽  
Cristina Ardean ◽  
Corneliu Mircea Davidescu ◽  
Adina Negrea ◽  
Mihaela Ciopec ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Maximum Efficiency ◽  
Metallic Silver ◽  
Maximum Adsorption Capacity ◽  
Silver Recovery ◽  
Equilibrium Studies ◽  
Environment Friendly ◽  
Modified Chitosan ◽  
Materials Used

The aim of this study is to investigate the silver recovery from aqueous solutions. There are a variety of recovery methods, such as hydrometallurgical, bio-metallurgical, cementation, reduction, electrocoagulation, electrodialysis, ion exchange, etc. Adsorption represents a convenient, environment friendly procedure, that can be used to recover silver from aqueous solutions. In this paper we highlight the silver adsorption mechanism on chitosan chemically modified with active groups, through kinetic, thermodynamic, and equilibrium studies. A maximum adsorption capacity of 103.6 mg Ag(I)/g of adsorbent for an initial concentration of 700 mg/L was noticed by using modified chitosan. Lower adsorption capacity has been noticed in unmodified chitosan—a maximum of 75.43 mg Ag(I)/g. Optimum contact time was 120 min and the process had a maximum efficiency when conducted at pH higher than 6. At the same time, a way is presented to obtain metallic silver from the adsorbent materials used for the recovery of the silver from aqueous solutions.

Ouricuri (Syagrus coronata) fiber: a novel biosorbent to remove methylene blue from aqueous solutions

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 ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Experimental Design ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Adsorption Process ◽  
Fiber Diameter ◽  
Aqueous Media ◽  
Process Efficiency ◽  
Maximum Adsorption Capacity ◽  
Equilibrium Studies

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.

scholarly journals Removal of Cu(II) from Aqueous Solutions Using Amine-Doped Polyacrylonitrile Fibers

2020 ◽  
Vol 10 (5) ◽  
pp. 1738
Author(s):  
Kay Thwe Aung ◽  
Seung-Hee Hong ◽  
Seong-Jik Park ◽  
Chang-Gu Lee
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Isotherm Models ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Equilibrium Studies ◽  
Naoh Solution ◽  
Surface Modified ◽  
Pan Fibers

Polyacrylonitrile (PAN) fibers were prepared via electrospinning and were modified with diethylenetriamine (DETA) to fabricate surface-modified PAN fibers. The surface-modified PAN fibers were used to evaluate their adsorption capacity for the removal of Cu(II) from aqueous solutions. Batch adsorption experiments were performed to examine the effects of the modification process, initial concentration, initial pH, and adsorbent dose on the adsorption of Cu(II). Kinetic analysis revealed that the experimental data fitted the pseudo-second-order kinetic model better than the pseudo-first-order model. Adsorption equilibrium studies were conducted using the Freundlich and Langmuir isotherm models, and the findings indicated that the PAN fibers modified with 85% DETA presented the highest adsorption capacity for Cu(II) of all analyzed samples. Moreover, the results revealed that the Freundlich model was more appropriate than the Langmuir one for describing the adsorption of Cu(II) onto the modified fibers at various initial Cu(II) concentrations. The maximum adsorption capacity was determined to be 87.77 mg/g at pH 4, and the percent removal of Cu(II) increased as the amount of adsorbent increased. Furthermore, the surface-modified PAN fibers could be easily regenerated using NaOH solution. Therefore, surface-modified PAN fibers could be used as adsorbents for the removal of Cu(II) from aqueous solutions.

scholarly journals Eco-materials for Arsenium and Selenium Removal from Aqueous Solutions

2019 ◽  
Vol 70 (5) ◽  
pp. 1586-1591
Author(s):  
Vasile Minzatu ◽  
Corneliu Mircea Davidescu ◽  
Mihaela Ciopec ◽  
Petru Negrea ◽  
Narcis Duteanu ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Natural Waters ◽  
Human Life ◽  
Maximum Adsorption Capacity ◽  
Animal Life ◽  
Equilibrium Studies ◽  
Acute Toxic Effect ◽  
Selenium Removal ◽  
A New Technique

Environmental engineering have a great importance because is dealing with different fields, most important of them being water resource protection. It is well known that natural waters and especially groundwater contain dissolved substances, most of them unharmful for human and animal life, but some of them still potentially harmful. Ground waters containing dissolved arsenic and / or selenium are harmful and not suitable for human an animal life. Selenium represents a human life prerequisite microelement which can become toxic when higher quantities are ingested or accumulated. In comparison arsenic has an acute toxic effect over the human body even when very low quantities are ingested. In both cases the maximum amount were limited by OMS at 10 mg L-1. A new technique was used to produce an ecofriendly composite material by doping graphite with iron oxide, which was used for retention of arsenic and selenium from aqueous solutions. Synthesized material was characterized using SEM, EDX, XRD and DTA. Adsorption capacity and adsorption mechanism were established through equilibrium studies. Maximum adsorption capacity was 400 �g As(V) and 625 �g Se(VI) per gram of adsorbent.

scholarly journals Enhanced Adsorption of Bisphenol A from Aqueous Solution with 2-Vinylpyridine Functionalized Magnetic Nanoparticles

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1136 ◽  
Author(s):  
Qiang Li ◽  
Fei Pan ◽  
Wentao Li ◽  
Dongya Li ◽  
Haiming Xu ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Magnetic Nanoparticle ◽  
Maximum Adsorption Capacity ◽  
Salting Out ◽  
Functionalized Magnetic Nanoparticles ◽  
Ft Ir ◽  
Fe3o4 Nanospheres ◽  
Enhanced Adsorption

In this study, a novel 2-vinylpyridine functionalized magnetic nanoparticle (Mag-PVP) was successfully prepared. The prepared Mag-PVP was characterized by transmission electronic microscopy (TEM), Fourier transform infrared spectrophotometry (FT-IR), vibrating sample magnetometry (VSM) and thermogravimetric analysis (TGA), and was used for the adsorption of bisphenol A (BPA) from aqueous solutions. Mag-PVP, which is composed of Fe3O4 nanoparticles and poly divinylbenzene-2-vinylpyridine (with a thickness of 10 nm), exhibited magnetic properties (Ms = 44.6 emu/g) and thermal stability. The maximum adsorption capacity (Qm) of Mag-PVP for BPA obtained from the Langmuir isotherm was 115.87 mg/g at 20 °C, which was more than that of Fe3O4 nanospheres. In the presence of NaCl, the improved adsorption capacity of Mag-PVP was probably attributed to the screening effect of Mag-PVP surface charge and salting-out effect. In the presence of CaCl2 and humic acid (HA), the adsorption capacity of BPA decreased due to competitive adsorption. The adsorption of BPA by Mag-PVP increased slightly with the increase in pH from 3.0 to 5.0 and obtained the largest adsorption amount at pH 5.0, which was probably attributed to hydrogen bonding interactions. Moreover, in actual water, Mag-PVP still showed excellent adsorption performance in removing BPA. The high adsorption capacity and excellent reusability performance in this work indicated that Mag-PVP was an effective adsorbent for removing BPA from aqueous solutions.

scholarly journals Fabrication of Carboxymethylcellulose/Metal-Organic Framework Beads for Removal of Pb(II) from Aqueous Solution

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 942 ◽  
Author(s):  
Huo-Xi Jin ◽  
Hong Xu ◽  
Nan Wang ◽  
Li-Ye Yang ◽  
Yang-Guang Wang ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Langmuir Isotherm ◽  
Adsorption Equilibrium ◽  
Isotherm Model ◽  
Maximum Adsorption Capacity ◽  
X Ray ◽  
Metal Organic ◽  
Langmuir Isotherm Model

The ability to remove toxic heavy metals, such as Pb(II), from the environment is an important objective from both human-health and ecological perspectives. Herein, we describe the fabrication of a novel carboxymethylcellulose-coated metal organic material (MOF-5–CMC) adsorbent that removed lead ions from aqueous solutions. The adsorption material was characterized by Fourier-transform infrared spectroscopy, X-ray diffractometry, scanning electron microscopy, and X-ray photoelectron spectroscopy. We studied the functions of the contact time, pH, the original concentration of the Pb(II) solution, and adsorption temperature on adsorption capacity. MOF-5–CMC beads exhibit good adsorption performance; the maximum adsorption capacity obtained from the Langmuir isotherm-model is 322.58 mg/g, and the adsorption equilibrium was reached in 120 min at a concentration of 300 mg/L. The adsorption kinetics is well described by pseudo-second-order kinetics, and the adsorption equilibrium data are well fitted to the Langmuir isotherm model (R2 = 0.988). Thermodynamics experiments indicate that the adsorption process is both spontaneous and endothermic. In addition, the adsorbent is reusable. We conclude that MOF-5–CMC is a good adsorbent that can be used to remove Pb(II) from aqueous solutions.

scholarly journals Synthesis characterization and sorption properties of a sorbent synthesized using slag and red mud: Arsenic removal from spiked aqueous solutions

2016 ◽  
Vol 18 (2) ◽  
pp. 339-347 ◽  
Keyword(s):  
Aqueous Solutions ◽  
Red Mud ◽  
Arsenic Removal ◽  
Point Of Zero Charge ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
Equilibrium Studies ◽  
Metallurgical Wastes ◽  
Bet Method ◽  
Gf Aas

<p>The aim of the present study was to synthesize a sorbent, for arsenic removal from aqueous solutions, reusing two waste materials (slag and red mud). The sorbent was prepared after chemical and thermal treatment, during which amorphous silica sol and FeOOH sol were produced simultaneously and form Fe-Si complexes on the surface of the slag. To characterize the sorbent Powder X-ray diffraction (XRD); Fourier transform infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM-EDX) were applied. The surface area (BET method) and the Point of Zero Charge (PZC) of the sorbent were determined.). The sorption efficiency of the sorbent produced was investigated with kinetic and equilibrium studies, performed in batch conditions. The concentration of arsenic in solutions was determined by electro thermal atomic absorption spectroscopy (GF-AAS). The results of the study showed that with the described process, using metallurgical wastes, iron oxyhydroxides were &ldquo;loaded&rdquo; onto slag producing an effective sorbent for arsenic removal. Kinetic experiments proved that equilibrium was achieved within 15 hours, while the maximum adsorption capacity as evidenced by equilibrium experiments, was 16.14 mg g<sup>-1</sup>. Data proved to fit better to the Langmuir equation.</p>

scholarly journals Adsorption Study of Cu2+ Ions from Aqueous Solutions by Bael Flowers (Aegle marmelos)

2020 ◽  
Vol 11 (4) ◽  
pp. 11891-11904
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Metal Ion ◽  
Low Cost ◽  
Sem Analysis ◽  
Ion Concentration ◽  
Maximum Adsorption Capacity ◽  
Aegle Marmelos ◽  
Batch Mode ◽  
Initial Ph

In the present study, batch mode adsorption was carried out to investigate the adsorption capacity of dried bael flowers (Aegle marmelos) for the adsorptive removal of Cu(II) ions from aqueous solutions by varying agitation time, initial metal concentration, the dose of adsorbent, temperature, and initial pH of the Cu(II) ion solution. The percentage removal of 98.7% was observed at 50 ppm initial metal ion concentration, 0.5 g/100.00 cm3 adsorbent dosage, within the contact time of 120 minutes at 30 ºC in the pH range of 4 – 7. The sorption processes of Cu(II) ions was best described by pseudo-second-order kinetics. Langmuir isotherm had a good fit with the experimental data with 0.97 of correlation coefficient (R2), and the maximum adsorption capacity obtained was 23.14 mg g-1 at 30 ºC. The results obtained from sorption thermodynamic studies suggested that the adsorption process is exothermic and spontaneous. SEM analysis showed tubular voids on the adsorbent. FTIR studies indicated the presence of functional groups like hydroxyl, –C-O, –C=O, and amide groups in the adsorbent, which can probably involve in metal ion adsorption. Therefore, dried bael flowers can be considered an effective low-cost adsorbent for treating Cu(II) ions.

scholarly journals Equilibrium and Kinetic Study of Lead and Copper Ion Adsorption on Chitosan-Grafted-Polyacrylic Acid Synthesized by Surface Initiated Atomic Transfer Polymerization

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2218 ◽  
Author(s):  
Carlos Grande-Tovar ◽  
William Vallejo ◽  
Fabio Zuluaga
Keyword(s):  
Adsorption Capacity ◽  
Polyacrylic Acid ◽  
Adsorption Process ◽  
Kinetic Constant ◽  
Copper Ion ◽  
Toxic Metal ◽  
Maximum Adsorption Capacity ◽  
Order Model ◽  
Equilibrium Studies ◽  
Pseudo Second Order

In this work, we synthesized chitosan grafted-polyacrylic acid (CS-g-PA) through surface-initiated atom transfer radical polymerization (SI-ATRP). We also studied the adsorption process of copper and lead ions onto the CS-g-PA surface. Adsorption equilibrium studies indicated that pH 4.0 was the best pH for the adsorption process and the maximum adsorption capacity over CS-g-PA for Pb2+ ions was 98 mg·g−1 and for Cu2+ it was 164 mg·g−1, while for chitosan alone (CS), the Pb2+ adsorption capacity was only 14.8 mg·g−1 and for Cu2+ it was 140 mg·g−1. Furthermore, the adsorption studies indicated that Langmuir model describes all the experimental data and besides, pseudo-second-order model was suitable to describe kinetic results for the adsorption process, demonstrating a larger kinetic constant of the process was larger for Pb2+ than Cu2+. Compared to other adsorbents reported, CS-g-PA had comparable or even superior adsorbent capacity and besides, all these results suggest that the new CS-g-PA polymers had potential as an adsorbent for hazardous and toxic metal ions produced by different industries.

Application of Carbonaceous Materials to Phenol Removal from Aqueous Solution by Adsorption

2012 ◽  
Vol 164 ◽  
pp. 297-301 ◽  
Author(s):  
Wei Fang Dong ◽  
Li Hua Zang ◽  
Qing Chao Gong ◽  
Cun Cun Chen ◽  
Cai Hong Zheng ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Petroleum Coke ◽  
Granular Activated Carbon ◽  
Powdered Activated Carbon ◽  
Maximum Adsorption Capacity ◽  
Phenol Removal ◽  
Carbonaceous Materials ◽  
Solution Ph ◽  
Equilibrium Studies

Low cost carbonaceous materials were evaluated for their ability to remove phenol from wastewater. The effects of adsorbents dosage, contact time and maximum adsorption capacity were investigated for granular activated carbon, powdered activated carbon, petroleum coke and multi-walled carbon nanotube (MWNT). Equilibrium studies were conducted in 50mg/L initial phenol concentration, solution pH of 5 and at temperature of 23°C. The results showed the adsorption process was fast and it reached equilibrium in 3 h. Petroleum coke and MWNT had poor adsorption which could reach the removal efficiency of phenol with 43.18% and 36.64% respectively. The granular activated carbon possessed good adsorption ability to phenol with 96.40% at the optimum dosage 5g and optimum time 90min.The powdered activated carbon was an effective adsorbent with a maximum adsorption capacity of 42.32 mg/g.

Novel Amphoteric Cryogels for Cd2+ Ions Removal from Aqueous Solutions

2018 ◽  
Vol 775 ◽  
pp. 376-382 ◽  
Author(s):  
Alzhan Baimenov ◽  
Dmitriy Berillo ◽  
Leila Abylgazina ◽  
Stavros G. Poulopoulos ◽  
Vassilis J. Inglezakis
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Chemical Structure ◽  
Nitrogen Adsorption ◽  
Maximum Adsorption Capacity ◽  
Cadmium Ions ◽  
Texture Analyzer ◽  
Ph Values ◽  
Amphoteric Properties ◽  
Scanning Electron

In this work, amphoteric cryogels based on N,N-dimethyl acrylamide, methacrylic acid and allylamine, crosslinked by N,N-methylenebisacrylamide were synthesized by free-radical polymerization in cryo-conditions. The synthesized cryogels were used for the removal of cadmium ions from aqueous solutions under different pH values. The chemical structure was studied by FTIR, porosity by nitrogen adsorption and morphology by scanning electron microscopy and texture analyzer. The amphoteric properties of cryogels were studied by zeta potential measurements. Adsorption tests revealed that cryogels exhibit 3 times higher adsorption capacity at pH 6.0 than at pH 4.0. The maximum adsorption capacity of the amphoteric cryogels for Cd2+ was 113 mg/g, at pH 6.0 and initial Cd2+ concentration 100 ppm. The results suggest that the predominant removal mechanism is ion exchange between sodium, which initially presents in the structure of the cryogel, and cadmium from the aqueous phase. Recovery studies suggested that the cryogels used can be regenerated and efficiently reused.

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