scholarly journals Synthesis of Mg-Al Hydrotalcite Clay with High Adsorption Capacity

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7231
Author(s):  
Zhaoyi Li ◽  
Jie Zhang ◽  
Chengtun Qu ◽  
Ying Tang ◽  
Michal Slaný
Keyword(s):  
Metal Oxides ◽  
Filter Paper ◽  
Adsorption Model ◽  
Hydrothermal Conditions ◽  
Uniform Dispersion ◽  
Hierarchical Porous ◽  
Pseudo Second Order ◽  
Oxide Particles ◽  
Paper Fibers ◽  
20 Nm

A novel Mg-Al metal oxide has been successfully synthesized by the calcination of hierarchical porous Mg-Al hydrotalcite clay obtained by using filter paper as a template under hydrothermal conditions. Various characterizations of the obtained nanoscale oxide particles verified the uniform dispersion of Mg-Al metal oxides on the filter paper fiber, which had a size of 2–20 nm and a highest specific surface area (SSA) of 178.84 m2/g. Structural characterization revealed that the as-prepared Mg-Al metal oxides preserved the tubular morphology of the filter paper fibers. Further experiments showed that the as-synthesized Mg-Al metal oxides, present at concentrations of 0.3 g/L, could efficiently remove sulfonated lignite from oilfield wastewater (initial concentration of 200 mg/L) in a neutral environment (pH = 7) at a temperature of 298 K. An investigation of the reaction kinetics found that the adsorption process of sulfonated lignite (SL) on biomorphic Mg-Al metal oxides fits a Langmuir adsorption model and pseudo-second-order rate equation. Thermodynamic calculations propose that the adsorption of sulfonated lignite was spontaneous, endothermic, and a thermodynamically feasible process.

scholarly journals Experimental and Theoretical Studies of Methyl Orange Uptake by Mn–Rich Synthetic Mica: Insights into Manganese Role in Adsorption and Selectivity

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1464
Author(s):  
Mohamed A. Barakat ◽  
Ali Q. Selim ◽  
Mohamed Mobarak ◽  
Rajeev Kumar ◽  
Ioannis Anastopoulos ◽  
...  
Keyword(s):  
Methyl Orange ◽  
Active Sites ◽  
Adsorption Model ◽  
Hydrothermal Conditions ◽  
Octahedral Sheet ◽  
Temperature Range ◽  
Synthetic Mica ◽  
Pseudo Second Order ◽  
Experimental And Theoretical Studies

Manganese–containing mica (Mn–mica) was synthesized at 200 °C/96 h using Mn–carbonate, Al–nitrate, silicic acid, and high KOH concentration under hydrothermal conditions. Mn–mica was characterized and tested as a new adsorbent for the removal of methyl orange (MO) dye from aqueous solutions. Compared to naturally occurring mica, the Mn–mica with manganese in the octahedral sheet resulted in enhanced MO uptake by four times at pH 3.0 and 25 °C. The pseudo–second order equation for kinetics and Freundlich equation for adsorption isotherm fitted well to the experimental data at all adsorption temperatures (i.e., 25, 40 and 55 °C). The decrease of Langmuir uptake capacity from 107.3 to 92.76 mg·g−1 within the temperature range of 25–55 °C suggested that MO adsorption is an exothermic process. The role of manganese in MO selectivity and the adsorption mechanism was analyzed via the physicochemical parameters of a multilayer adsorption model. The aggregated number of MO ions per Mn–mica active site ( n ) was superior to unity at all temperatures signifying a vertical geometry and a mechanism of multi–interactions. The active sites number (DM) of Mn–mica and the total removed MO layers (Nt) slightly changed with temperature. The decrease in the MO adsorption capacities (Qsat = n·DM·Nt) from 190.44 to 140.33 mg·g−1 in the temperature range of 25–55 °C was mainly controlled by the n parameter. The results of adsorption energies revealed that MO uptake was an exothermic (i.e., negative ΔE values) and a physisorption process (ΔE < 40 kJ mol −1). Accordingly, the adsorption of MO onto Mn–mica was governed by the number of active sites and the adsorption energy. This study offers insights into the manganese control of the interactions between MO ions and Mn–mica active sites.

Facile preparation of hierarchical porous 2MgO · B2O3 · 2H2O nanostructure with ultra-high adsorption performance for triphenylmethane dyes removal

2020 ◽  
Vol 10 (10) ◽  
pp. 1668-1676
Author(s):  
Rui-Feng Guo ◽  
Wen-Ru Ma ◽  
Ming-Zhen Wang ◽  
Zhi-Hong Liu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Triphenylmethane Dyes ◽  
Hierarchical Porous ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Adsorption Kinetics And Isotherm ◽  
20 Nm ◽  
Treatment Application

The fan-like 2MgO · B2O3 · 2H2O porous nanostructures were prepared by a solvothermal approach. FT-IR, XRD, TG-DTA, SEM, and TEM were used to characterize the obtained sample, which was constructed by nanobelts with 20 nm in width, about 5 nm in thickness and 2 μm in length. Its specific surface area was measured as 118.94 m2/g. It exhibited ultra-high removal of triphenylmethane dyes for AF, MG and BF from aqueous solution, in which the maximum adsorption capacities are much higher than those of most reported adsorbents. The higher absorption for triphenylmethane dyes can be attributed to the positive surface charge, the main existing mesopores and macropores, and larger specific surface area of the prepared 2MgO · B2O3 · 2H2O sample, which make the absorbent and anionic dye molecules existing both the stronger electrostatic attraction and hydrogen bonds of N–H· · · O and O–H· · · N. The adsorption kinetics and isotherm were found to conform to pseudo-second-order model and Langmuir model. The competitive adsorption for BF and MG and the adsorption mechanism were also investigated. The as-prepared sample is of larger adsorption capacity and good reusability, which makes it valuable in potential wastewater treatment application.

Influence of Thermo-Mechanical Processing on the Microstructure of Beryllia Dispersed Nickel Alloys

1973 ◽  
Vol 31 ◽  
pp. 184-185
Author(s):  
M.S. Grewal ◽  
S.A. Sastri ◽  
N.J. Grant
Keyword(s):  
High Temperature ◽  
Nickel Alloys ◽  
Thermomechanical Processing ◽  
Cold Work ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Mechanical Processing ◽  
Uniform Dispersion ◽  
Oxide Particles ◽  
Nickel Base

Currently there is a great interest in developing nickel base alloys with fine and uniform dispersion of stable oxide particles, for high temperature applications. It is well known that the high temperature strength and stability of an oxide dispersed alloy can be greatly improved by appropriate thermomechanical processing, but the mechanism of this strengthening effect is not well understood. This investigation was undertaken to study the dislocation substructures formed in beryllia dispersed nickel alloys as a function of cold work both with and without intermediate anneals. Two alloys, one Ni-lv/oBeo and other Ni-4.5Mo-30Co-2v/oBeo were investigated. The influence of the substructures produced by Thermo-Mechanical Processing (TMP) on the high temperature creep properties of these alloys was also evaluated.

scholarly journals Optimization of cadmium(II) adsorption onto modified and unmodified lignocellulosics (rice husk and egussi peeling)

2015 ◽  
Vol 5 (1) ◽  
pp. 45
Author(s):  
Tchuifon Tchuifon Donald Raoul ◽  
Nche George Ndifor-Angwafor ◽  
Ngakou Sadeu Christian ◽  
Kamgaing Théophile ◽  
Ngomo Horace Manga ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Rice Husk ◽  
Order Kinetic ◽  
Adsorption Model ◽  
Batch Technique ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Adsorbed Quantity ◽  
Minimal Mass ◽  
Modified Adsorbents

<p>The present study is based on the adsorption of cadmium (II) ions on rice husk and egussi peeling, unmodified and modified with nitric acid in aqueous solution, using batch technique. It was carried out as a function of contact time, dosage, pH and initial concentration. The equilibrium time was achieved within 25 minutes for unmodified rice husk (Glu NT) and 20 minutes for unmodified egussi peeling (Cuc NT) with an adsorbed quantity of 13.18 mg/g. In the case of modified materials, we obtained 15 minutes for modified rice husk (Glu HNO3) and 10 minutes for modified egussi peeling (Cuc HNO3) with an adsorbed quantity of 18.77 mg/g. The maximum biosorption occurred at pH 5.5 for all biosorbents. The adsorbent mass for maximum adsorption was 0.4 g giving an adsorption capacity of 62.02 % for unmodified adsorbents. In the case of modified adsorbents, the minimal mass at which maximum adsorption occurred was 0.4 g giving an adsorption capacity of 98.33 % and 0.6 g giving an adsorption capacity of 98.33 % for modified rice husk and egussi peeling respectively. The adsorbent/adsorbate equilibrium was well described by the pseudo-second order kinetic model and by Langmuir’s and Freundlich adsorption model. This models showed that the adsorption of cadmium (II) is a chemisorption process.</p>

scholarly journals THE USE OF NANOSCALE ZINC OXIDE IN WOOD-BASED COMPOSITIONS

2021 ◽  
Author(s):  
S. Neminushchaya ◽  
E. Tomina ◽  
A. Dmitrenkov
Keyword(s):  
Zinc Oxide ◽  
Vegetable Oil ◽  
Zinc Oxide Nanoparticles ◽  
Sol Gel ◽  
Environmental Safety ◽  
Oxide Nanoparticles ◽  
Natural Wood ◽  
Oxide Particles ◽  
Used Vegetable Oil ◽  
20 Nm

The aim of this work was to study compositions based on vegetable oil waste and nanoscale zinc oxide particles for processing natural wood. The sol-gel method was used for the synthesis of zinc oxide nanoparticles. The synthesized zinc oxide nanoparticles did not contain impurities and had a shape close to spherical, and their size did not exceed 20 nm. We used freshly prepared suspensions of zinc oxide nanoparticles in used vegetable oil with their content in the amount of 0.1, 0.5 and 1.0 wt. parts per 100 parts of oil. The wood was treated by hot-cold impregnation. The tests were carried out on samples of birch and pine wood of standard sizes. In the modified samples, the wetting angle, moisture and water absorption, as well as their swelling were determined. It is shown that the use of zinc oxide nanoparticles in compositions based on vegetable oil waste can significantly reduce the moisture and water resistance of wood and reduce its swelling. The optimal dosages of the nanopowder introduced into the used vegetable oil and the conditions of impregnation were selected. The compositions used on the basis of vegetable oil waste are characterized by environmental safety, and the resulting wood samples had an improved appearance.

scholarly journals Efficient Hydrophobic Modification of Old Newspaper and Its Application in Paper Fiber Reinforced Composites

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 842 ◽  
Author(s):  
Weiwei Zhang ◽  
Jin Gu ◽  
Dengyun Tu ◽  
Litao Guan ◽  
Chuanshuang Hu
Keyword(s):  
Mechanical Properties ◽  
Aspect Ratio ◽  
Natural Fiber ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Oh Groups ◽  
Uniform Dispersion ◽  
The Matrix ◽  
Paper Fibers

Paper fibers have gained broad attention in natural fiber reinforced composites in recent years. The specific problem in preparing paper fiber reinforced composites is that paper fibers easily become flocculent after pulverization, which increases difficulties during melt-compounding with polymer matrix and results in non-uniform dispersion of paper fibers in the matrix. In this study, old newspaper (ONP) was treated with a low dosage of gaseous methyltrichlorosilane (MTCS) to solve the flocculation. The modified ONP fibers were characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Thermogravimetric Analysis (TG). Then the modified ONP fibers and high-density polyethylene (HDPE) were extruded and pelletized to prepare ONP/HDPE composites via injection molding. Maleic anhydride-grafted polyethylene (MAPE) was added to enhance the interfacial bonding performance with the ultimate purpose of improving the mechanical strength of the composites. The mechanical properties such as tensile, flexural, and impact strength and the water absorption properties of the composite were tested. The results showed that the formation of hydrogen bonding between ONP fibers was effectively prevented after MTCS treatment due to the reduction of exposed –OH groups at the fiber surface. Excessive dosage of MTCS led to severe fiber degradation and dramatically reduced the aspect ratio of ONP fibers. Composites prepared with ONP fibers modified with 4% (v/w) MTCS showed the best mechanical properties due to reduced polarity between the fibers and the matrix, and the relatively long aspect ratio of treated ONP fibers. The composite with or without MAPE showed satisfactory water resistance properties. MTCS was proven to be a cheap and efficient way to pretreat old newspaper for preparing paper fiber reinforced composites.

scholarly journals Enhanced Phenol Tert-Butylation Reaction Activity over Hierarchical Porous Silica-Alumina Materials

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1098
Author(s):  
Ling Xu ◽  
Fan Wang ◽  
Zhi Xiu ◽  
Limei Duan ◽  
Zongrui Liu ◽  
...  
Keyword(s):  
Physical Adsorption ◽  
Porous Silica ◽  
Mesoporous Structure ◽  
Catalytic Performance ◽  
Crystallization Time ◽  
Hydrothermal Conditions ◽  
Transmission Electron ◽  
Hierarchical Porous ◽  
Silica Alumina ◽  
Ft Ir

Hierarchical aluminum-silicon materials have been successfully prepared by mixing pre-crystallization of silica-alumina sol and citric acid under hydrothermal conditions. The influence of pre-crystallization time on the micro-mesoporous structure is studied using Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), N2 physical adsorption, and high-resolution transmission electron microscopy (HRTEM). The catalytic performance of hierarchical silica-alumina material is evaluated by alkylation of phenol with tert-butanol. The results show that the silica-alumina materials with a pre-crystallization time of 16 h show micro-mesoporous structure and excellent catalytic activity.

scholarly journals Sodium hydroxide modified rice husk for enhanced removal of copper ions

2018 ◽  
Vol 78 (7) ◽  
pp. 1615-1623 ◽  
Author(s):  
N. Priyantha ◽  
H. K. W. Sandamali ◽  
T. P. K. Kulasooriya
Keyword(s):  
Heavy Metal ◽  
Adsorption Capacity ◽  
Rice Husk ◽  
Copper Ions ◽  
Maximum Adsorption Capacity ◽  
Adsorption Model ◽  
Natural Form ◽  
Langmuir Adsorption ◽  
Pseudo Second Order ◽  
Heavy Metal Adsorbent

Abstract Although rice husk (RH) is a readily available, natural, heavy metal adsorbent, adsorption capacity in its natural form is insufficient for certain heavy metal ions. In this context, the study is based on enhancement of the adsorption capacity of RH for Cu(II). NaOH modified rice husk (SRH) shows higher extent of removal for Cu(II) ions than that of heated rice husk (HRH) and HNO3 modified rice husk (NRH). The extent of removal of SRH is increased with the concentration of NaOH, and the optimum NaOH concentration is 0.2 mol dm−3, used to modify rice husk for further studies. The surface area of SRH is 215 m2 g−1, which is twice as much as that of HRH according to previous studies. The sorption of Cu(II) on SRH obeys the Langmuir adsorption model, leading to the maximum adsorption capacity of 1.19 × 104 mg kg−1. Kinetics studies show that the interaction of Cu(II) with SRH obeys pseudo second order kinetics. The X-ray fluorescence spectroscopy confirms the adsorption of Cu(II) on SRH, while desorption studies confirm that Cu(II) adsorbed on SRH does not leach it back to water under normal conditions.

scholarly journals Cyclodextrin modified filter paper for removal of cationic dyes/Cu ions from aqueous solutions

2018 ◽  
Vol 78 (12) ◽  
pp. 2553-2563 ◽  
Author(s):  
Yaoyue Li ◽  
Yanbo Zhou ◽  
Yi Zhou ◽  
Juying Lei ◽  
Shengyan Pu
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Filter Paper ◽  
Textile Industry ◽  
High Efficiency ◽  
National Standard ◽  
Esterification Reaction ◽  
Dynamic Adsorption ◽  
Pseudo Second Order ◽  
Cu Ions

Abstract A filter paper was functionalized with β-cyclodextrin and citric acid via esterification reaction for the removal of dyes and Cu ions from aqueous solutions. The adsorption capacity and removal performance of the modified filter paper (MFP) was investigated using static and dynamic adsorption experiments. The static adsorption data fit well the Langmuir and pseudo-second-order models, and the adsorption capacity of Methylene Blue (MB), Brilliant Green (BG), Rhodamine-B (RB) and Cu(II) over the MFP were 124.6 mg/g, 130.4 mg/g, 99.7 mg/g and 39.1 mg/g, respectively, which are much higher than the unmodified filter paper (below 2 mg/g). Even better, the decolorization performance and Cu(II) removal of MFP are remarkable in dynamic adsorption. The effluent can reach the National Standard for dyeing and finishing of textile industry of China after three cycles in a continuous filtration-adsorption system. This method provides a new pathway to achieve high efficiency removal of dyes and metal ions from wastewater.

scholarly journals Effects of Pretreatment with Ionic Liquids on Cellulose Hydrolysis under Hydrothermal Conditions

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3572 ◽  
Author(s):  
Toshitaka Funazukuri ◽  
Shingo Ozawa
Keyword(s):  
Ionic Liquids ◽  
Filter Paper ◽  
Biomass Conversion ◽  
Batch Reactor ◽  
Cellulose Hydrolysis ◽  
Reaction Rates ◽  
Crystalline Cellulose ◽  
Hydrothermal Conditions ◽  
Imidazolium Chloride ◽  
Product Yields

Hydrothermal hydrolysis in hot pressurized liquid water (HPLW) is attractive for biomass conversion into valuable products because it achieves high reaction rates without catalysts and additives. The hydrothermal hydrolysis of high crystalline cellulose requires higher reaction temperature than polysaccharides having low crystallinity. It can be expected to increase the reaction rate or decrease temperature by decreasing the crystallinity. In the present study ashless filter paper as a fibrous pure cellulose sample was pretreated with ionic liquids (ILs) such as imidazolium chloride ILs containing alkyl side chains ranging from two to six carbons, and with an aqueous solution of bis(ethylenediamine ammonium) copper (BEDC). Herein, the pretreatment with ILs was to regenerate filter paper: dissolving in ILs at 373 K for 120 min or in an aqueous BEDC solution at room temperature, precipitating by adding water, washing the solid, and then drying. Subsequently, the pretreated filter paper samples were hydrolyzed at 533 K and 5.0 MPa in HPLW in a small semi-batch reactor, and the effects of the pretreatment with ILs or BEDC on reaction rates and product yields were examined. While the crystallinity indexes with all ILs and BEDC after the pretreatments decreased to 44 to 47 from the original sample of 87, the reaction rates and product yields were significantly affected by the IL species. At 533 K and 5.0 MPa, the dissolution rate with [AMIM][Cl] was nine times as fast as that for untreated sample.

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