The change in structure of surfactant aggregates during adsorption/desorption processes and its effect on the stability of alumina suspension

The separation of C3H4/C3H6 is one of the most energy intensive and challenging operations, requiring up to 100 theoretical stages, in traditional cryogenic distillation. In this investigation, the potential application of two MOFs (SIFSIX-3-Ni and NbOFFIVE-1-Ni) was tested by studying the adsorption–desorption behaviors at a range of operational temperatures (300–360 K) and pressures (1–100 kPa). Dynamic adsorption breakthrough tests were conducted and the stability and regeneration ability of the MOFs were established after eight consecutive cycles. In order to establish the engineering key parameters, the experimental data were fitted to four isotherm models (Langmuir, Freundlich, Sips and Toth) in addition to the estimation of the thermodynamic properties such as the isosteric heats of adsorption. The selectivity of the separation was tested by applying ideal adsorbed solution theory (IAST). The results revealed that SIFSIX-3-Ni is an effective adsorbent for the separation of 10/90 v/v C3H4/C3H6 under the range of experimental conditions used in this study. The maximum adsorption reported for the same combination was 3.2 mmolg−1. Breakthrough curves confirmed the suitability of this material for the separation with a 10-min gab before the lighter C3H4 is eluted from the column. The separated C3H6 was obtained with a 99.98% purity.

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Sorption and Desorption Analysis of Nitrobenzene on Differently Functionalized Multiwalled Carbon Nanotubes and Implications on the Stability

Water ◽

10.3390/w13101426 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1426

Author(s):

Zhanhua Ji ◽

Dengyu Li

Keyword(s):

Carbon Nanotubes ◽

Underlying Mechanism ◽

Multiwalled Carbon ◽

Environmental Behaviors ◽

Initial Concentration ◽

Sorption Hysteresis ◽

Key Factor ◽

Functionalized Multiwalled Carbon Nanotubes ◽

The Stability ◽

Adsorption Desorption

The stability of carbon nanotubes (CNTs) suspension is a key factor in determining their transport, fate, and toxicity in an aquatic environment, which is significantly influenced by CNTs’ nature and water chemistry. Macromolecular dissolved organic matter (DOM) is reported to influence the stability of CNTs aggregation. However, little is known on small polar dissolved organic compound’s effects on CNTs aggregation. Nitrobenzene was selected to investigate its interaction with three different functionalized multiwalled CNTs (MWCNTs). Both the stability of CNTs aggregation and sorption hysteresis were affected by the initial concentration of nitrobenzene and the surface functionalization coverage of MWCNTs. At the initial concentration below 580 mg/L, the thermodynamic index of irreversibility (TII) and turbidity of CNTs suspension had the same tendency, indicating that the underlying mechanism is closely related. A conceptual adsorption–desorption model was proposed to further explain the relationship between the sorption hysteresis and stability of MWCNTs suspension under different initial concentrations of nitrobenzene. This provided data support to further clarify the environmental behaviors and risks of CNTs.

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Synthesis of Magnetic Targeted Cellulose Composite Decorated with Poly(AA-DMC) for Synergistic Adsorption Degradation of Congo Red from Organic Wastewater

10.21203/rs.3.rs-453687/v1 ◽

2021 ◽

Author(s):

Chen Ling ◽

Dai Yimin ◽

Lu Qi ◽

Fang Chengqian ◽

Wang Zhiheng ◽

...

Keyword(s):

Congo Red ◽

Magnetic Particles ◽

Degradation Mechanism ◽

Degradation Of Dyes ◽

Cellulose Composites ◽

Natural Cellulose ◽

The Stability ◽

Adsorption Desorption ◽

Cr Removal ◽

Organic Wastewater

Abstract A brand-new environmental-friendly magnetic cellulosic adsorbent MnFe2O4@Cel-g-p(AA-DMC) was synthesized by natural cellulose and easy-recovered magnetic particles MnFe2O4. Magnetic cellulose composites were characterized by SEM, TEM, XPS, XRD, BET, VSM, TGA and FTIR. The MnFe2O4NPs could activate the peroxymonosulfate (PMS) to produce various reactive oxygen species (ROS). Accordingly, magnetic cellulose composites can synergistic adsorption degradation of dyes from organic wastewater. The Congo red (CR) removal efficiency by MnFe2O4@Cel-g-p(AA-DMC) via PMS activated by MnFe2O4 reached a maximum of 96.9% and only 9% reduction after four adsorption-desorption cycles, indicating the stability and recoverability of adsorbent. It is worth noting that adsorbents can be quickly recovered from aqueous solution by external magnet owing to superior saturation magnetization (35.44 emu·g-1). A possible degradation mechanism of CR on the MnFe2O4@Cel-g-p(AA-DMC) composite was proposed. The results suggest that adsorbent display strong potential for the removal of CR dyes from organic wastewater.

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The Utilization of Mg-Al/Cu as Selective Adsorbent for Cationic Synthetic Dyes

BULLETIN OF CHEMICAL REACTION ENGINEERING AND CATALYSIS ◽

10.9767/bcrec.16.4.11043.696-706 ◽

2021 ◽

Vol 16 (4) ◽

pp. 696-706

Author(s):

Arini Fousty Badri ◽

Neza Rahayu Palapa ◽

Risfidian Mohadi ◽

Mardiyanto Mardiyanto ◽

Fitri Suryani Arsyad ◽

...

Keyword(s):

Adsorption Capacity ◽

Cationic Dyes ◽

Synthetic Dyes ◽

Batch System ◽

Ft Ir ◽

Materials Used ◽

The Stability ◽

Co Precipitation ◽

Adsorption Desorption ◽

Open Access Article

Mg-Al-LDH is a chemical compound produced through co-precipitation technique and modified with Cu(NO3)2.6H2O to form Mg-Al/Cu. However, the research on the capability of these compounds for adsorbing mixtures of cationic dyes as well as malachite green (MG), methylene blue (MB), and Rodhamine-B (Rh-B) has not been carried out. Therefore, this research aims to determine the performance of Mg-Al-LDH and Mg-Al/Cu for removing cationic dyes. The materials used were characterized by using XRD powder, FT-IR, and N2 adsorption desorption. The Adsorption process was conducted by batch system and several effects were investigated, such as kinetic parameter, isotherm, and the temperature condition. The stability feature of Mg-Al-LDH and Mg-Al/Cu was obtained from the regeneration process in the five cycles. The results presented that Mg-Al/Cu was effectively produced, which was indicated by the formation of layer at 10.792° (003), 22.94° (006), 35.53° (112), 55.78° (110), and 56.59° (116). Mg-Al-LDH and Mg-Al/Cu were found to adsorbed MG than the other cationic dyes with adsorption capacity of 68.996 mg/g and 104.167 mg/g, respectively. The unique properties of Mg-Al/Cu includes, structural stability towards the reuse of adsorbent subsequently for five times, without significant decrease of adsorption capacity. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

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Two-Step Synthesis of Ca-Based MgO Hybrid Adsorbent for Potential CO2 Capturing Application

Materials Science Forum ◽

10.4028/www.scientific.net/msf.981.369 ◽

2020 ◽

Vol 981 ◽

pp. 369-374

Author(s):

Farah Diana Mohd Daud ◽

Nurul Amirah Izzati Ahmad ◽

Mudrikah Sofia Mahmud ◽

Norshahida Sariffudin ◽

Hafizah Hanim Mohd Zaki

Keyword(s):

Carbon Capture ◽

Carbon Capture And Storage ◽

Xrd Analysis ◽

Magnesium Nitrate ◽

Synthesis Methods ◽

Step Method ◽

Support Materials ◽

Solid Sorbents ◽

The Stability ◽

Adsorption Desorption

Carbon capture and storage (CCS) is one of the method in reducing carbon dioxide (CO2) emissions into the atmosphere. CO2 capturing using calcium oxide (CaO) solid sorbents has been considered as an advanced concept for CO2 capture and recovery. However, the adsorption capacity of CaO decreases during repeated adsorption/desorption cycles. The stability of Ca-based sorbents during cyclic runs can be achieved via the incorporation of inert support materials. Among the available inert materials, MgO is most promising for CO2 due to high stability and a high Tammann temperature. Most of Ca- based MgO hybrid adsorbent synthesis methods sorbent come with its own limitations which are longer synthesis duration and complex or multistep methods. In this research, Ca-based MgO hybrid adsorbent was prepared via two-step method. Calcium acetate and magnesium nitrate as precursor had dissolved in water, follow by addition of ethanol. The mixture then became gelated and proceeded for calcination at 550°C and 650°C. The prepared sorbent was characterized by Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) and fourier transfer infrared spectroscopy (FTIR). The XRD analysis of the Ca-based MgO hybrid adsorbent showed the existence of MgO,CaO and CaCO3. FTIR analysis showed presence of Ca─O bond and Mg═O bond. The morphology of the hybrid adsorbent was found to be spherical to granular shape and agglomerated. The Ca- based MgO hybrid adsorbent structural and morphological shows great potential for CO2 capturing capacity over multiple carbonation cycles for CO2 capturing application.

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Mg-Al/Biochar Composite with Stable Structure for Malachite Green Adsorption from Aqueous Solutions

BULLETIN OF CHEMICAL REACTION ENGINEERING AND CATALYSIS ◽

10.9767/bcrec.16.1.10270.149-160 ◽

2021 ◽

Vol 16 (1) ◽

pp. 149-160

Author(s):

Arini Fousty Badri ◽

Patimah Mega Syah Bahar Nur Siregar ◽

Neza Rahayu Palapa ◽

Risfidian Mohadi ◽

Mardiyanto Mardiyanto ◽

...

Keyword(s):

Malachite Green ◽

Physical Adsorption ◽

Stable Structure ◽

Maximum Adsorption Capacity ◽

X Ray Diffraction ◽

Effects Of Temperature ◽

The Stability ◽

Double Hydroxide ◽

Adsorption Desorption ◽

Open Access Article

Mg-Al-layered double hydroxide (LDH) was fabricated using a coprecipitation method at pH 10. Thereafter, Mg-Al-LDH was impregnated with biochar to manufacture a Mg-Al/Biochar composite. The composite was characterized using powder X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, N2 adsorption—desorption, thermogravimetry-differential thermal analysis (TG-DTA), and scanning electron microscopy (SEM) experiments, and was subsequently used for malachite green (MG) adsorption. MG adsorption experiments were performed in a batch system, and the effects of temperature and adsorption kinetic and isotherm parameters on the adsorption process were analyzed. The stability of Mg-Al/Biochar was evaluated using regeneration experiments over three cycles. The peaks at 11.47° (003), 22.86° (002), 34.69° (012), and 61.62° (116), in the XRD profile of Mg-Al/Biochar suggested that Mg-Al/Biochar was successfully fabricated. The surface area of Mg-Al/Biochar was up to five times larger than that of pristine Mg-Al-LDH. The adsorption of MG on Mg-Al/Biochar was dominated by interactions at the surface of the adsorbent and was classified as physical adsorption; moreover the maximum adsorption capacity ofMg-Al/Biochar was 70.922 mg/g. Furthermore, the MG removal of Mg-Al/Biochar during three successive adsorption cycles (i.e. 66.73%, 65.57%, and 65.77% for the first, second, and third adsorption cycle) did not change significantly, which indicated the stable structure of the adsorbent. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

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Nanoparticles of Ni-Co Alloy Derived from Layered Double Hydroxides and Their Catalytic Performance for CO Methanation

NANO ◽

10.1142/s1793292016501186 ◽

2016 ◽

Vol 11 (10) ◽

pp. 1650118 ◽

Cited By ~ 6

Author(s):

Jingge Liu ◽

Ang Cao ◽

Jing Si ◽

Lihong Zhang ◽

Qinglan Hao ◽

...

Keyword(s):

Metallic Nanoparticles ◽

Carbon Deposition ◽

Catalytic Performance ◽

X Ray Diffraction ◽

Co Methanation ◽

Transmission Electron ◽

Temperature Programmed ◽

The Stability ◽

Double Hydroxides ◽

Adsorption Desorption

Sintering of the active metallic nanoparticles and carbon deposition are the key problems faced for CO methanation catalysts. For overcoming those problems, bimetallic nanocatalyst is a promising route. In this work, a series of Al2O3 supported Ni-Co alloy catalysts were prepared by reducing NiCoAl layered double hydrotalcite (LDHs), and characterized with X-ray diffraction (XRD), temperature programmed reduction TPR, N2 adsorption-desorption, transmission electron microscopy (TEM) and temperature programed oxidation (TPO) techniques. The resultant catalysts were mesoporous with nanoparticles of Ni-Co alloy ranging from 7.9[Formula: see text]nm to 9.2[Formula: see text]nm which were highly dispersed in alumina matrix. The sample Ni7Co3-Al2O3 catalysts showed very good catalytic performance during the stability test at 500/600[Formula: see text]C for 300[Formula: see text]h, meanwhile exhibited excellent anti-sintering ability and anti-carbon deposition ability, owing to the formation of Ni-Co alloy and the feature of LDHs. This strategy for improving anti-sintering and anti-carbon deposition should be extendable for catalysts of other reactions.

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Aqueous synthesis of highly adsorptive copper–gallic acid metal–organic framework

Scientific Reports ◽

10.1038/s41598-020-75927-4 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Badril Azhar ◽

Artik Elisa Angkawijaya ◽

Shella Permatasari Santoso ◽

Chintya Gunarto ◽

Aning Ayucitra ◽

...

Keyword(s):

Gallic Acid ◽

Metal Organic Framework ◽

Synthesis Temperature ◽

Molar Ratio ◽

Aqueous Synthesis ◽

Synthesis Conditions ◽

Metal Organic ◽

The Stability ◽

Adsorption Desorption ◽

Organic Framework

Abstract A greener route to synthesize mesoporous copper–gallic acid metal–organic framework (CuGA MOF) than the conventional method using harmful DMF solvent was proposed in this study. Various synthesis attempts were conducted by modifying the synthesis conditions to produce CuGA MOF with comparable physical properties to a reference material (DMF-synthesized CuGA NMOF). The independent variables investigated include the molar ratio of NaOH to GA (1.1 to 4.4) and the synthesis temperature (30, 60, 90 °C). It was found that proper NaOH addition was crucial for suppressing the generation of copper oxide while maximizing the formation of CuGA MOF. On the other hand, the reaction temperature mainly affected the stability and adsorption potential of CuGA MOF. Reacting Cu, GA, and NaOH at a molar ratio of 1:1:2.2 and a temperature of 90 °C, produced mesoporous MOF (CuGA 90–2.2) with a surface area of 198.22 m2/g, a pore diameter of 8.6 nm, and a thermal stability of 219 °C. This MOF exhibited an excellent adsorption capacity for the removal of methylene blue (124.64 mg/g) and congo red (344.54 mg/g). The potential usage of CuGA 90–2.2 as a reusable adsorbent was demonstrated by its high adsorption efficiency (> 90%) after 5 adsorption–desorption cycles.

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CO2 Adsorption from Biogas Using Amine-Functionalized MgO

International Journal of Chemical Engineering ◽

10.1155/2018/1706405 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Preecha Kasikamphaiboon ◽

Uraiwan Khunjan

Keyword(s):

Adsorption Capacity ◽

X Ray Diffraction ◽

Wet Impregnation ◽

Heating Value ◽

Amine Functionalized ◽

Adsorption Capacities ◽

Impregnation Technique ◽

The Stability ◽

Adsorption Desorption ◽

Fuel Source

Biogas is a renewable fuel source of methane (CH4), and its utilization as a natural gas substitute or transport fuel has received much interest. However, apart from CH4, biogas also contains carbon dioxide (CO2) which is noncombustible, thus reducing the biogas heating value. Therefore, upgrading biogas by removing CO2 is needed for most biogas applications. In this study, an amine-functionalized adsorbent for CO2 capture from biogas was developed. Mesoporous MgO was synthesized and functionalized with different tetraethylenepentamine (TEPA) loadings by wet impregnation technique. The prepared adsorbents (MgO-TEPA) were characterized by X-ray diffraction (XRD) and N2 adsorption-desorption. The CO2 adsorption performance of the prepared MgO-TEPA was tested using simulated biogas as feed gas stream. The results show that the CO2 adsorption capacities of the adsorbents increase with increasing TEPA loading. The optimum TEPA loading is 40 wt.%, which gives the highest CO2 adsorption capacity of 4.98 mmol/g. A further increase in TEPA loading to 50 wt.% significantly reduces the CO2 adsorption capacity. Furthermore, the stability and regenerability of the adsorbent with 40% TEPA loading (MgO-TEPA-40) were studied by performing ten adsorption-desorption cycles under simulated biogas and real biogas conditions. After ten adsorption-desorption cycles, MgO-TEPA-40 shows slight decreases of only 5.42 and 5.75% of CO2 adsorption capacity for the simulated biogas and biogas, respectively. The results demonstrate that MgO-TEPA-40 possesses good stability and regenerability which are important for the potential application of this amine-based adsorbent.

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Release of Pharmaceutical Peptides in an Aggregated State: Using Fibrillar Polymorphism to Modulate Release Levels

Colloids and Interfaces ◽

10.3390/colloids3010042 ◽

2019 ◽

Vol 3 (1) ◽

pp. 42 ◽

Cited By ~ 3

Author(s):

Jens Madsen ◽

Gunna Christiansen ◽

Lise Giehm ◽

Daniel Otzen

Keyword(s):

Control Release ◽

Proteinase K ◽

Sustained Delivery ◽

Soluble Peptide ◽

Surfactant Aggregates ◽

Dodecyl Maltoside ◽

Multiple Cycles ◽

The Stability ◽

Traditional Approaches ◽

Release Profiles

Traditional approaches to achieve sustained delivery of pharmaceutical peptides traditionally use co-excipients (e.g., microspheres and hydrogels). Here, we investigate the release of an amyloidogenic glucagon analogue (3474) from an aggregated state and the influence of surfactants on this process. The formulation of peptide 3474 in dodecyl maltoside (DDM), rhamnolipid (RL), and sophorolipid (SL) led to faster fibrillation. When the aggregates were subjected to multiple cycles of release by repeated resuspension in fresh buffer, the kinetics of the release of soluble peptide 3474 from different surfactant aggregates all followed a simple exponential decay fit, with half-lives of 5–18 min and relatively constant levels of release in each cycle. However, different amounts of peptide are released from different aggregates, ranging from 0.015 mg/mL (3475-buffer) up to 0.03 mg/mL (3474-DDM), with 3474-buffer and 3474-RL in between. In addition to higher release levels, 3474-DDM aggregates showed a different amyloid FTIR structure, compared to 3474-RL and 3474-SL aggregates and a faster rate of degradation by proteinase K. This demonstrates that the stability of organized peptide aggregates can be modulated to achieve differences in release of soluble peptides, thus coupling aggregate polymorphism to differential release profiles. We achieved aggregate polymorphism by the addition of different surfactants, but polymorphism may also be reached through other approaches, including different excipients as well as changes in pH and salinity, providing a versatile handle to control release profiles.

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