scholarly journals Functionalization of Fe3O4/SiO2 with N-(2-Aminoethyl)-3-aminopropyl for Sorption of [AuCl4]-

2018 ◽  
Vol 16 (2) ◽  
pp. 130 ◽  
Author(s):  
Nuryono Nuryono ◽  
Mighfar Syukur ◽  
Agus Kuncaka ◽  
Satya Candra Wibawa Sakti

Synthesis of Fe3O4/SiO2 modified with N-(2-aminoethyl)-3-aminopropyl group (Fe3O4/SiO2/ED) via coating method and its application for adsorption-desorption of anionic gold in aqueous solution have been conducted. The synthesized product was characterized with an X-ray diffractometer (XRD), a Fourier transform infrared (FT-IR) spectrophotometer and a transmission electron microscopy (TEM). Adsorption of Au(III) was conducted in a batch system and the variables included pH, contact time, and initial concentration were investigated. Results showed that magnetite/silica has been successfully functionalized with N-(2-aminoethyl)-3-aminopropyl in a homogeneous system. Kinetics study showed that adsorption of Au(III) followed the pseudo-second order model with rate constant of 0.710 g mmol L-1min-1. Furthermore, the experimental data fitted well with the Langmuir isotherm model with the maximum adsorption capacity for Au(III) of 142.9 mg g-1 and the energy of 25.0 kJ mol-1. Gold loaded on the Fe3O4/SiO2/ED could be easily desorbed with 0.2 mol L-1 HCl containing 2 wt.% of thiourea with recovery of 99.8%. Fe3O4/SiO2/ED was reusable and stable in 5 cycles of adsorption-desorption with recovery more than 90%. Fe3O4/SiO2/ED showed high selectivity towards Au(III) in the multimetal system Au(III)/Cu(II)/Cr(VI) with the coefficient selectivity for αAu-Cu of 227.5and for αAu-Cr of 12.3.

2017 ◽  
Vol 76 (9) ◽  
pp. 2526-2534 ◽  
Author(s):  
Meimei Zhou ◽  
Weizhen Tang ◽  
Pingping Luo ◽  
Jiqiang Lyu ◽  
Aixia Chen ◽  
...  

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.


Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1449 ◽  
Author(s):  
Xianchun Hu ◽  
Xianfeng Du

Microporous starch (MPS) granules were formed by the partial hydrolysis of starch using α–amylase and glucoamylase. Due to its biodegradability and safety, MPS was employed to adsorb tea polyphenols (TPS) based on their microporous characteristics. The influences of solution pH, time, initial concentration and temperature on the adsorptive capacity were investigated. The adsorption kinetics data conformed to the pseudo second–order kinetics model, and the equilibrium adsorption data were well described by the Langmuir isotherm model. According to the fitting of the adsorption isotherm formula, the maximum adsorption capacity of TPS onto MPS at pH 6.7 and T = 293 K was approximately 63.1 mg/g. The thermodynamic parameters suggested that the adsorption of TPS onto MPS was spontaneous and exothermic. Fourier transform infrared (FT–IR) analysis and the thermodynamics data were consistent with a physical adsorption mechanism. In addition, MPS-loaded TPS had better stability during long-term storage at ambient temperature.


2019 ◽  
Vol 80 (7) ◽  
pp. 1357-1366
Author(s):  
Jianming Liu ◽  
Runying Bai ◽  
Junfeng Hao ◽  
Bowen Song ◽  
Yu Zhang ◽  
...  

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.


2015 ◽  
Vol 71 (11) ◽  
pp. 1611-1619 ◽  
Author(s):  
Jun Liu ◽  
Hongyan Du ◽  
Shaowei Yuan ◽  
Wanxia He ◽  
Pengju Yan ◽  
...  

Alkaline deoxygenated graphene oxide (aGO) was prepared through alkaline hydrothermal treatment and used as adsorbent to remove Cd(II) ions from aqueous solutions for the first time. The characterization results of transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and Fourier transform infrared (FT-IR) spectra indicate that aGO was successfully synthesized. The batch adsorption experiments showed that the adsorption kinetics could be described by the pseudo-second-order kinetic model, and the isotherms equilibrium data were well fitted with the Langmuir model. The maximum adsorption capacity of Cd(II) on aGO was 156 mg/g at pH 5 and T = 293 K. The adsorption thermodynamic parameters indicated that the adsorption process was a spontaneous and endothermic reaction. The mainly adsorption mechanism speculated from FT-IR results may be attributed to the electrostatic attraction between Cd2+ and negatively charged groups (–CO−) of aGO and cation-π interaction between Cd2+ and the graphene planes. The findings of this study demonstrate the potential utility of the nanomaterial aGO as an effective adsorbent for Cd(II) removal from aqueous solutions.


2020 ◽  
Vol 860 ◽  
pp. 338-344
Author(s):  
Iis Nurhasanah ◽  
Kadarisman ◽  
Vincensius Gunawan ◽  
Heri Sutanto

This study explored adsorptive property of ceria nanocrystal as an adsorbent for amoxicillin removal from water. Ceria nanocrystal was synthesized by employing precipitation method and characterized by using XRD and N2 adsorption-desorption analysis. The adsorption experiment was performed by managing amoxicillin in natural condition. Then, parameters in the adsorption experiment, such as adsorbent dosage, contact time, temperature and initial concentration of amoxicillin are varied. The XRD pattern illustrated that the average crystallite size of ceria nanocrystal formation was 13.08 nm. N2 adsorption-desorption analysis showed that ceria nanocrystal was mesoporous with specific surface area of ​​65.26 m2/g. The amoxicillin adsorption of ceria nanocrystal adsorbent was described by Langmuir isotherm model with maximum adsorption capacity of 37.17 mg/g. The adsorption kinetic of ceria nanocrystal corresponded to the pseudo-second order model. Removal efficiency of amoxicillin by ceria nanocrystal was approximately 80% within 60 minutes over temperature range 303-323K. Those parameter results are described that ceria nanocrystal adsorbent is feasible as a rapid amoxicillin removal from water.


2017 ◽  
Vol 75 (7) ◽  
pp. 1651-1658 ◽  
Author(s):  
Hongyu Jia ◽  
Ningning Liu

Nanoporous polydivinylbenzene (PDVB) material has been successfully prepared via the copolymerization of divinylbenzene monomers. The nanoporous PDVB was characterized through N2 adsorption/desorption isotherms, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The nanoporous PDVB as an adsorbent was applied for the removal of Rhodamine B (RhB). The adsorption behavior of PDVB for the removal of RhB showed that the isotherm data followed the Langmuir isotherm model and the kinetic adsorption obeyed the pseudo-second-order model. Thermodynamic parameters illustrated that the adsorption process was spontaneous and exothermic. Interestingly, the spent nanoporous PDVB has excellent regenerative performance through treating it with ethanol. These results revealed that PDVB might be an excellent adsorbent for the removal of RhB from wastewater.


2021 ◽  
Vol 12 (4) ◽  
pp. 4584-4596

The activated carbon investigated in this work was produced from the extractive residues of Brazil nut processing, more specifically from the mesocarp of the Amazonian fruit. The process was performed by muffle pyrolysis, with ZnCl2 impregnation, at 400 and 500 °C. All samples were characterized by X-ray diffractometry, thermogravimetry, CHNS elemental analysis, scanning electron microscopy, and adsorption/desorption of N2. The results were promissory, with 99% removal of methylene blue for the CA25 material, which has a surface area of 1236 m2 g-1, much higher than commercial coal (CAC, 618 m2 g-1). The adsorption kinetics best fit the pseudo-second-order model for all materials. The maximum adsorption capacity obtained was 195.3 mg g-1. Therefore, the extractive residue of Brazil nut has excellent potential for the development of activated carbon, which can be used effectively to mediate environmental contamination in a given aqueous medium.


2012 ◽  
Vol 209-211 ◽  
pp. 2005-2008 ◽  
Author(s):  
Fang Juan Zhang ◽  
Hua Yong Zhang ◽  
Lu Yi Zhang

The feasibility of coal gangue as an adsorbent for phosphate removal from wastewater was investigated. The results showed that the equilibrium data were well fit to Langmuir isotherm model and the maximum adsorption capacity calculated was 2.49 mg/g at 25°C. The adsorption process followed pseudo-second order model. And the practical waste water experiment indecated that the phosphate concentration of real sewage decreased from 0.625mg/L to 0.121mg/L. These results suggested that coal gangue can be used as an adsorbent to removal phosphate from wastewater.


Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3092
Author(s):  
Jianchuan Sun ◽  
Awang Gao ◽  
Xuhui Wang ◽  
Xiangyu Xu ◽  
Jiaqing Song

In this work, an organic-free method was used to synthesize different morphological boehmite by controlling the crystallization temperature, and alumina adsorbents were obtained by baking the boehmites at 500 °C. The alumina adsorbents were characterized by X-ray diffraction (XRD), High resolution transmission electron microscope (HRTEM), Fourier transform infrared (FT-IR), N2 adsorption/desorption analysis, and their phosphorus adsorption properties were comparatively investigated by a series of experiments. The results showed that the self-prepared alumina adsorbents were lamellar and fibrous material, while the industrial adsorbent was a granular material. The lamellar alumina adsorbents had the largest specific surface area and showed better phosphorus adsorption capacity. The maximum adsorption capacity could reach up to 588.2 mg·g−1; and only 0.8 g·L−1 of lamellar alumina adsorbent is needed to treat 100 mg·L−1 phosphorus solution under the Chinese level 1 discharge standard (0.5 mg·L−1). Further investigation suggests that the lamellar alumina adsorbent kept high adsorption capacity in various solution environments.


2011 ◽  
Vol 13 (4) ◽  
pp. 84-88 ◽  
Author(s):  
Wan Khalir ◽  
Megat Hanafiah ◽  
Siti So'ad ◽  
Wan Ngah

Adsorption behavior of Pb(II) onto xanthated rubber (Hevea brasiliensis) leaf powder A plant waste, rubber (Hevea brasiliensis) leaf powder was modified with carbon disulfide (xanthation) for the purpose of introducing sulfur groups, and the adsorbent performance in removing Pb(II) ion was evaluated. Pb(II) adsorption was confirmed by spectroscopic analysis, which involved Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The amount of Pb(II) adsorbed increased with increasing pH, contact time and concentration but slightly decreased with increasing ionic strength. Adsorption equilibrium was achieved in less than 60 min and followed the pseudo-second order model. The isotherm data indicated that Pb(II) adsorption on xanthated rubber leaf (XRL) fitted well with Langmuir isotherm model. The maximum adsorption capacity computed from the Langmuir isotherm model was 166.7 mg/g. Pb(II) adsorption occurred via ion-exchange and complexation mechanisms.


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