Novel reusable hydrogel adsorbents for precious metal recycle

AbstractA novel polyethylene glycol diacrylate-allylthiourea (ATU-PEGDA) hydrogel was simply synthesized through photo-reaction. Modified thiourea simultaneously employed chelation and electrostatic force to selectively recycle Ag(I) and Pd(II) from electrolytic wastewater. Sorption efficiency was nearly 100% for Ag(I) and Pd(II), which occurred at initial pH of 1 within 300 min. The adsorption characteristics of ATU-PEGDA followed Langmuir isotherm model and the maximum adsorption capacity of Ag(I) and Pd(II) achieved 83.33 and 152.81 mg g−1 sorbent, respectively where Pseudo-first order model demonstrate the adsorption kinetics. In the presence of other heavy metals, ATU-PEGDA performed high selectivity, 0.89 and 1.31 towards Ag(I) and Pd(II). ATU-PEGDA can be completely regenerated within 120 min using 0.5 M thiourea—0.001 M HNO3 and 1 M thiourea—4 M HCl after the adsorption of Ag(I) and Pd(II), respectively. Thiourea-branched structure was created after regeneration, improving the adsorption capacity. Compared to initial hydrogel, the adsorption capacity of Ag(I) and Pd(II) increased 31.83 ± 3.08% and 75.12 ± 11.02%, respectively. Over 10 consecutive adsorption–desorption cycles, ATU-PEGDA performed 111.34 and 263.79 mg g−1 sorbent in adsorption capacity of Ag(I) and Pd(II). Chromism of ATU-PEGDA hydrogel was a benefit to determine adsorption saturation and completely desorption of Ag(I) and Pd(II). Potentially, ATU-PEGDA can be extended to industrial applications.

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Adsorption of Crystal Violet oNto Nitrogen-Doped Mesoporous Carbon

Progress in Reaction Kinetics and Mechanism ◽

10.3184/146867817x14821527549211 ◽

2017 ◽

Vol 42 (3) ◽

pp. 269-281

Author(s):

Lvling Zhong ◽

Liang Zhang ◽

Hongliang Shi

Keyword(s):

Adsorption Capacity ◽

Crystal Violet ◽

Photoelectron Spectroscopy ◽

Control Process ◽

Maximum Adsorption Capacity ◽

Nitrogen Doped ◽

First Order Kinetics ◽

Equilibrium Data ◽

Langmuir Isotherm Model ◽

Adsorption Desorption

A series of nitrogen-doped mesoporous carbons (NDMCs) was prepared using p-phenylenediamine and glyoxal as a carbon source and mesoporous silica as a hard template. N2 adsorption–desorption isotherms indicated that mesopores with a wider distribution exist in NDMCs. Elemental analysis showed that the N content on the surface of NDMC-800 was 9.9at.%, with a result close to 8.4at.% from X-ray photoelectron spectroscopy. The adsorption capacity of NDMCs for crystal violet (CV) in aqueous solution was investigated. Static equilibrium data were well described by the Langmuir isotherm model, with a maximum adsorption capacity of 243.9 mg g−1. Adsorption kinetics data suggested that the adsorption control process follows the pseudo first-order kinetics model. The results showed that this carbon material has the potential for application in adsorption of CV.

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Self-Regeneration Hybrid Hydrogel for Bisphenol A Adsorption in Water

10.21203/rs.3.rs-661488/v1 ◽

2021 ◽

Author(s):

Mingyue Piao ◽

Hongxue Du ◽

Yuwei Sun ◽

Honghui Teng

Keyword(s):

Bisphenol A ◽

Adsorption Capacity ◽

Freundlich Isotherm ◽

Significant Loss ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

Hybrid Hydrogel ◽

Polyethylene Glycol Diacrylate ◽

Glycol Diacrylate ◽

Pseudo Second Order

Abstract Hybrid hydrogel was synthesized by immobilizing TiO2 in polyethylene glycol diacrylate (TiO2@PEGDA) as an efficient adsorbent with photocatalysis property for bisphenol A (BPA) elimination. TiO2@PEGDA exhibited spherical and rough structure with limited crystallinity and abundant functional groups. The contact angle was 61.96°, indicating that TiO2@PEGDA is hydrophilic. The swelling capacity of TiO2@PEGDA (9.0%) was decreased compared with pristine PEGDA (15.6%). Adsorption results demonstrated that the maximum adsorption capacity of TiO2@PEGDA (101.4 mg/g) for BPA was slightly higher than pristine PEGDA (97.68 mg/g). The adsorption capacity was independent with pH at pH ＜ 8.0, and decreased obviously when the value of pH was higher than 8.0. The adsorption behavior was fitted well with the pseudo-second-order kinetic and the Freundlich isotherm model. Both ΔG0 and ΔH0 were negative, indicating that BPA adsorbed on TiO2@PEGDA was an exothermic and spontaneous process. Regeneration study was performed by photocatalysis, and the adsorption capacity was 85.6% compared with the initial capacity after four cycles of illumination, indicating that TiO2@PEGDA could be recycled without significant loss of adsorption capacity. Consequently, TiO2@PEGDA can serve as an eco-friendly and promising material for efficiently adsorbing BPA with self-clean property.

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Hydrazinolyzed cellulose-g-polymethyl acrylate as adsorbent for efficient removal of Cd(II) and Pb(II) ions from aqueous solution

Water Science & Technology ◽

10.2166/wst.2016.581 ◽

2016 ◽

Vol 75 (5) ◽

pp. 1051-1058 ◽

Cited By ~ 5

Author(s):

Qiujin Jia ◽

Wanting Zhang ◽

Dongping Li ◽

Yulong Liu ◽

Yuju Che ◽

...

Keyword(s):

Aqueous Solution ◽

Adsorption Capacity ◽

Physical Adsorption ◽

Freundlich Isotherm ◽

Isotherm Model ◽

Initial Ph ◽

Langmuir Isotherm Model ◽

Pseudo Second Order ◽

Adsorption Desorption ◽

Efficient Adsorbent

Hydrazinolyzed cellulose-graft-polymethyl acrylate (Cell-g-PMA-HZ), an efficient adsorbent for removal of Cd(II) and Pb(II) from aqueous solution, has been prepared by ceric salt-initiated graft polymerization of methyl acrylate from microcrystalline cellulose surface and subsequent hydrazinolysis. The influences of initial pH, contact time, and temperature on adsorption capacity of Cell-g-PMA-HZ as well as adsorption equilibrium, kinetic and thermodynamic properties were examined in detail. As for Cd(II) adsorption, kinetic adsorption can be explained by pseudo-second-order, while adsorption isotherm fits well with Langmuir isotherm model, from which maximum equilibrium adsorption capacity can be derived as 235.85 mg g−1 at 28 °C. Further thermodynamic investigation indicated that adsorption of Cd(II) by adsorbent Cell-g-PMA-HZ is endothermic and spontaneous under studied conditions. On the other hand, isotherm of Pb(II) adsorption fits well with Freundlich isotherm model and is more likely to be a physical-adsorption-dominated process. Consecutive adsorption–desorption experiments showed that Cell-g-PMA-HZ is reusable with satisfactory adsorption capacity.

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Preparation of ureido-functionalized PVA/silica mesoporous fibre membranes via electrospinning for adsorption of Pb2+ and Cu2+ in wastewater

Water Science & Technology ◽

10.2166/wst.2017.405 ◽

2017 ◽

Vol 76 (9) ◽

pp. 2526-2534 ◽

Cited By ~ 6

Author(s):

Meimei Zhou ◽

Weizhen Tang ◽

Pingping Luo ◽

Jiqiang Lyu ◽

Aixia Chen ◽

...

Keyword(s):

Electron Microscopy ◽

Adsorption Capacity ◽

Freundlich Isotherm ◽

Isotherm Model ◽

Maximum Adsorption Capacity ◽

X Ray Diffraction ◽

Transmission Electron ◽

Langmuir Isotherm Model ◽

Pseudo Second Order ◽

Adsorption Desorption

Abstract Ureido-functionalized mesoporous polyvinyl alcohol/silica composite nanofibre membranes were prepared by electrospinning technology and their application for removal of Pb2+ and Cu2+ from wastewater was discussed. The characteristics of the membranes were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and N2 adsorption-desorption analysis. Results show that the membranes have long ﬁbrous shapes and worm-like mesoporous micromorphologies. Fourier transform infrared spectroscopy confirmed the membranes were successfully functionalized with ureido groups. Pb2+ and Cu2+ adsorption behavior on the membranes followed a pseudo-second-order nonlinear kinetic model with approximately 30 minutes to equilibrium. Pb2+ adsorption was modelled using a Langmuir isotherm model with maximum adsorption capacity of 26.96 mg g−1. However, Cu2+ adsorption was well described by a Freundlich isotherm model with poor adsorption potential due to the tendency to form chelating complexes with several ureido groups. Notably, the membranes were easily regenerated through acid treatment, and maintained adsorption capacity of 91.87% after five regeneration cycles, showing potential for applications in controlling heavy metals-related pollution and metals reuse.

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Biochar of Spent Coffee Grounds as Per Se and Impregnated with TiO2: Promising Waste-Derived Adsorbents for Balofloxacin

Molecules ◽

10.3390/molecules26082295 ◽

2021 ◽

Vol 26 (8) ◽

pp. 2295

Author(s):

Marwa El-Azazy ◽

Ahmed S. El-Shafie ◽

Hagar Morsy

Keyword(s):

Adsorption Capacity ◽

Batch Adsorption ◽

Maximum Adsorption Capacity ◽

Spent Coffee Grounds ◽

Thermal Stabilities ◽

Coffee Grounds ◽

Bet Analysis ◽

Pseudo Second Order ◽

Set Up ◽

Adsorption Desorption

Biochars (BC) of spent coffee grounds, both pristine (SCBC) and impregnated with titanium oxide (TiO2@SCBC) were exploited as environmentally friendly and economical sorbents for the fluroquinolone antibiotic balofloxacin (BALX). Surface morphology, functional moieties, and thermal stabilities of both adsorbents were scrutinized using SEM, EDS, TEM, BET, FTIR, Raman, and TG/dT analyses. BET analysis indicated that the impregnation with TiO2 has increased the surface area (50.54 m2/g) and decreased the pore size and volume. Batch adsorption experiments were completed in lights of the experimental set-up of Plackett-Burman design (PBD). Two responses were maximized; the % removal (%R) and the adsorption capacity (qe, mg/g) as a function of four variables: pH, adsorbent dosage (AD), BALX concentration ([BALX]), and contact time (CT). %R of 68.34% and 91.78% were accomplished using the pristine and TiO2@SCBC, respectively. Equilibrium isotherms indicated that Freundlich model was of a perfect fit for adsorption of BALX onto both adsorbents. Maximum adsorption capacity (qmax) of 142.55 mg/g for SCBC and 196.73 mg/g for the TiO2@SCBC. Kinetics of the adsorption process were best demonstrated using the pseudo-second order (PSO) model. The adsorption-desorption studies showed that both adsorbents could be restored with the adsorption efficiency being conserved up to 66.32% after the fifth cycles.

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

Materials ◽

10.3390/ma12060942 ◽

2019 ◽

Vol 12 (6) ◽

pp. 942 ◽

Cited By ~ 10

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.

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

Biointerface Research in Applied Chemistry ◽

10.33263/briac114.1189111904 ◽

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.

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Recovery of phosphate from aqueous solution by magnetically recycled modified polishing powder composites

Water Science & Technology ◽

10.2166/wst.2019.381 ◽

2019 ◽

Vol 80 (7) ◽

pp. 1357-1366

Author(s):

Jianming Liu ◽

Runying Bai ◽

Junfeng Hao ◽

Bowen Song ◽

Yu Zhang ◽

...

Keyword(s):

Adsorption Capacity ◽

Ligand Exchange ◽

Adsorption Process ◽

High Adsorption ◽

Order Model ◽

Powder Composites ◽

Langmuir Isotherm Model ◽

Pseudo Second Order ◽

Ph Level ◽

Adsorption Desorption

Abstract This study investigated a magnetically recycled modified polishing powder (CMIO@PP) as an adsorbent of phosphate; the CMIO@PP was synthesized by combining the modified La/Ce-containing waste polishing powder with CaO2-modified Fe3O4 (CMIO). Results indicate that the CMIO@PP nanocomposite presents a crystal structure comprising La (OH)3, Ce (OH)3, and Fe3O4, and that CMIO is uniformly dispersed in the modified polishing powder. The CMIO@PP (1:3) is a suitable choice considering its magnetism and adsorption capacity. The magnetic adsorbent exhibits a high adsorption capacity of 53.72 mg/g, a short equilibrium time of 60 min, and superior selectivity for phosphate. Moreover, the adsorbent strongly depends on the pH during the adsorption process and maintains a large adsorption capacity when the pH level is between 2 and 6. The adsorption of phosphate by the CMIO@PP (1:3) accords with the Langmuir isotherm model, and the adsorption process follows the pseudo-second order model. Meanwhile, adsorption–desorption experiments show that the adsorbent could be recycled a few times and that a high removal efficiency of phosphate from civil wastewater was achieved. Finally, mechanisms show that the adsorption of phosphate by the CMIO@PP (1:3) is mainly caused by electrostatic attraction and ligand exchange.

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Adsorption of cadmium(II) from aqueous solution onto activated carbon

Water Science & Technology ◽

10.2166/wst.1997.0278 ◽

1997 ◽

Vol 35 (7) ◽

pp. 205-211 ◽

Cited By ~ 51

Author(s):

R. Leyva-Ramos ◽

J. R. Rangel-Mendez ◽

J. Mendoza-Barron ◽

L. Fuentes-Rubio ◽

R. M. Guerrero-Coronado

Keyword(s):

Activated Carbon ◽

Adsorption Isotherm ◽

Adsorption Capacity ◽

Freundlich Isotherm ◽

Carbon Surface ◽

Maximum Adsorption Capacity ◽

Solution Ph ◽

Ph Values ◽

Average Percent Deviation ◽

Initial Ph

The adsorption isotherm of cadmium on activated carbon was measured in a batch adsorber. Effects of temperature and solution pH on the adsorption isotherm were investigated by determining the adsorption isotherm at temperatures of 10, 25, and 40°C and at initial pH values from 2 to 8. Langmuir isotherm better fitted the experimental data since the average percent deviation was lower than with the Freundlich isotherm It was noticed that the amount of Cd2+ adsorbed was reduced about 3 times by increasing the temperature from 10 to 40°C. It was found that Cd2+ was not adsorbed on activated carbon at pH of 2 or lower and that Cd2+ was precipitated out as Cd(OH)2 at pH values above 9. Maximum adsorption capacity was observed at pH of 8 and the adsorption capacity was decreased about 12 times by reducing the initial pH from 8 to 3. According to the cadmium speciation diagram the predominant species below pH of 8 is Cd2+. Thus, cadmium was adsorbed on the activated carbon surface as Cd2+. It was concluded that the adsorption capacity is a strong function of pH and temperature.

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Preparation of GO/MIL-101(Fe,Cu) composite and its adsorption mechanisms for phosphate in aqueous solution

10.21203/rs.3.rs-191207/v1 ◽

2021 ◽

Author(s):

You Wu ◽

Zuannian Liu ◽

Bakhtari Mohammad Fahim ◽

Junnan Luo

Keyword(s):

Adsorption Capacity ◽

Photoelectron Spectroscopy ◽

Adsorption Mechanism ◽

Nitrogen Adsorption ◽

Adsorption Properties ◽

Maximum Adsorption Capacity ◽

X Ray Diffraction ◽

X Ray ◽

Adsorption Mechanisms ◽

Adsorption Desorption

Abstract In this study, MIL-101(Fe), MIL-101(Fe,Cu), and Graphene Oxide (GO) /MIL-101(Fe,Cu) were synthesized to compose a novel sorbent. The adsorption properties of these three MOFs-based composites were compared toward the removal of phosphate. Furthermore, the influencing factors including reaction time, pH, temperature and initial concentration on the adsorption capacity of phosphate on these materials as well as the reusability of the material were discussed. The structure of fabricated materials and the removal mechanism of phosphate on the composite material were analyzed by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption analysis and zeta potential. The results show that the maximum adsorption capacity of phosphate by the composite GO/MIL-101(Fe,Cu)-2% was 204.60 mg·g− 1, which is higher than that of MIL-101(Fe,Cu) and MIL-101(Fe). likewise the specific surface area of GO/MIL-101(Fe,Cu)-2% is 778.11 m2/g is higher than that of MIL-101(Fe,Cu) and MIL-101(Fe),which are 747.75 and 510.66m2/g respectively. The adsorption mechanism of phosphate is electrostatic attraction, form coordination bonds and hydrogen bonds. The fabricated material is a promising adsorbent for the removal of phosphate with good reusability.

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