Organic-free large-pore-sized γ-alumina for the removal of three azo dyes from aqueous solution

2021 ◽  
Vol 11 (9) ◽  
pp. 1534-1545
Author(s):  
Xuhui Wang ◽  
Jianchuan Sun ◽  
Shuaiqi Chen ◽  
Shuai Ren ◽  
Awang Gao ◽  
...  
Keyword(s):  
Dye Adsorption ◽  
Specific Area ◽  
Kinetics Study ◽  
Order Model ◽  
Surface Areas ◽  
Adsorption Capacities ◽  
Direct Blue ◽  
Calculation Results ◽  
Specific Surface Areas ◽  
Adsorption Rates

A series of γ-alumina with different pore sizes (5.7 nm–21.6 nm) and similar specific surface areas were synthesized via an organic-free method and their adsorption rates and capacities for Congo red (CR), direct blue 78 (DB78) and direct green 26 (DG26) were investigated. The kinetics study reveals that the dye adsorptions of all γ-alumina samples fit the pseudo-2nd-order model. For CR, its k2 and the pore size of absorbent are in a linear relationship at low dye concentrations. Both of the experimental results and Langmuir isotherm calculation results suggest that the dye adsorption capacities of the γ-alumina prepared in our lab are much higher than those of other γ-alumina reported in literatures. GA-1 with the largest specific area of surface and largest size of pores exhibits a CR adsorption capacity up to 4213.6 mg/g. In addition, initial dye adsorption rates of the γ-alumina prepared in-house are much higher than that of the γ-alumina prepared with the commercially available alumina under the same conditions.

Facile synthesis of porous organic polymers for the absorption of Pd(ii) ions and organic dyes

RSC Advances ◽  
2016 ◽  
Vol 6 (83) ◽  
pp. 79781-79791 ◽  
Author(s):  
Yanmei Luo ◽  
Junhui Ran ◽  
Rong Chen ◽  
Xinjian Cheng
Keyword(s):  
Reaction Time ◽  
Specific Surface ◽  
Pore Diameter ◽  
Organic Dyes ◽  
Porous Structures ◽  
High Adsorption ◽  
Facile Synthesis ◽  
Surface Areas ◽  
Adsorption Capacities ◽  
Specific Surface Areas

Two kinds of POPs were synthesized with unique porous structures, considerable specific surface areas and high adsorption capacities. The specific surface area and pore diameter could be adjusted via changing the reaction time and temperature.

SO2 adsorption on acid-treated bentonites from Turkey

Clay Minerals ◽  
2011 ◽  
Vol 46 (1) ◽  
pp. 73-83 ◽  
Author(s):  
M. Sakizci ◽  
B. Erdoğan Alver ◽  
E. Yörükoğullari
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Sulphur Dioxide ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Adsorption Capacities ◽  
So2 Adsorption ◽  
Specific Surface Areas

AbstractThe adsorption of sulphur dioxide (SO2) on two bentonites from Unye, Turkey (Kavaktepe and Yemişlitepe deposits – denoted below as BK and BY) and on forms treated with 1 and 2 M HCl solutions was investigated. The bentonite samples were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), thermogravimetry (TG-DTG), differential thermal analysis (DTA) and nitrogen adsorption methods. Adsorption capacities of SO2 were obtained using a standard volumetric apparatus at 293 K and 106 kPa. The SO2 adsorption capacity of the BY-2 (1.263 mmol g–1) sample was much greater than the BK-2 (1.126 mmol g–1) sample. As the concentration of acid increased, the specific surface areas and the uptakes of SO2 gas increased.

scholarly journals Study on the Removal Performance of Phenol and Lead by Vernadite Synthesized via a New Method

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Baibing Wang ◽  
Nanqi Ouyang ◽  
Qin Zhang ◽  
Shizhang Zheng ◽  
Yang Li ◽  
...  
Keyword(s):  
Specific Surface ◽  
Active Sites ◽  
Phenol Degradation ◽  
Isothermal Adsorption ◽  
Intermediate Products ◽  
Surface Areas ◽  
Adsorption Capacities ◽  
Significant Difference ◽  
Specific Surface Areas ◽  
The Difference

Vernadite has excellent oxidation and adsorption performance, suggesting that it has good application prospects for the removal of phenolic substances and heavy metals from wastewater. In this study, after vernadite was synthesized by two different methods, the removal performance difference between the samples synthesized by the new and traditional methods (Ver-H and Ver-OH, respectively) was explored by sample characterization, phenol degradation, and Pb2+ adsorption experiments. The results show that, compared with Ver-OH, Ver-H has a larger particle size, specific surface areas, and total organic carbon (TOC) degradation capacity; the equilibrium degradation capacity of TOC of Ver-H was increased by 31.3%. The difference in the amount of TOC degradation may be attributed to more Mn(IV) oxygen vacancies in Ver-H, which facilitate the removal of intermediate products formed during phenol degradation. In addition, the larger specific surface areas provide the mineral surface with a larger number of active sites; Ver-H can therefore adsorb more intermediate products to promote their mineralization into CO2. The adsorptions of Pb2+ by Ver-H and Ver-OH are both consistent with Langmuir isothermal adsorption, and the maximum adsorption capacities are 569.79 g/kg and 623.10 g/kg, respectively. The lack of significant difference indicates that both vernadites have strong adsorption capacities for Pb2+.

scholarly journals Ultrafine porous boron nitride nanofibers synthesized via a freeze-drying and pyrolysis process and their adsorption properties

RSC Advances ◽  
2016 ◽  
Vol 6 (2) ◽  
pp. 1253-1259 ◽  
Author(s):  
Jing Lin ◽  
Lulu Xu ◽  
Yang Huang ◽  
Jie Li ◽  
Weijia Wang ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Specific Surface ◽  
Freeze Drying ◽  
Adsorption Properties ◽  
Pyrolysis Process ◽  
Surface Areas ◽  
Aspect Ratios ◽  
Large Pore ◽  
Specific Surface Areas

Ultrafine porous boron nitride nanofibers with high aspect ratios, high specific surface areas and large pore volumes has been synthesized in large quantity via a freeze-drying and post pyrolysis process.

scholarly journals Experimental Investigation of Coal Dust Wettability Based on Surface Contact Angle

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Gang Zhou ◽  
Han Qiu ◽  
Qi Zhang ◽  
Mao Xu ◽  
Jiayuan Wang ◽  
...  
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Specific Surface ◽  
Coal Dust ◽  
Single Point ◽  
Contact Angles ◽  
Critical Surface ◽  
Volume Percentage ◽  
Surface Areas ◽  
Specific Surface Areas

Wettability is one of the key chemical properties of coal dust, which is very important to dedusting. In this paper, the theory of liquid wetting solid was presented firstly; then, taking the gas coal of Xinglongzhuang coal mine in China as an example, by determination of critical surface tension of coal piece, it can be concluded that only when the surface tension of surfactant solution is less than 45 mN/m can the coal sample be fully wetted. Due to the effect of particle dispersity, compared with the contact angle of milled coal particle, not all the contact angles of screened coal powder with different sizes have a tendency to increase. Furthermore, by the experiments of coal samples’ specific surface areas and porosities, it can be achieved that the volume of single-point total pore decreases with the gradual decreasing of coal’s porosity, while the ultramicropores’ dispersities and multipoint BET specific surface areas increase. Besides, by a series of contact angle experiments with different surfactants, it can be found that with the increasing of porosity and the decreasing of volume percentage of ultramicropore, the contact angle tends to reduce gradually and the coal dust is much easier to get wetted.

scholarly journals Adsorption Characteristics of Phosphate Ions by Pristine, CaCl2 and FeCl3-Activated Biochars Originated from Tangerine Peels

Separations ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 32 ◽  
Author(s):  
Changgil Son ◽  
Wonyeol An ◽  
Geonhee Lee ◽  
Inho Jeong ◽  
Yong-Gu Lee ◽  
...  
Keyword(s):  
Adsorption Kinetics ◽  
Chemical Activation ◽  
Isotherm Models ◽  
Order Model ◽  
Phosphate Ions ◽  
Adsorption Capacities ◽  
Adsorption Isotherm Models ◽  
Endothermic Reactions ◽  
Pseudo Second Order ◽  
Adsorption Kinetics And Isotherm

This study has evaluated the removal efficiencies of phosphate ions (PO43−) using pristine (TB) and chemical-activated tangerine peel biochars. The adsorption kinetics and isotherm presented that the enhanced physicochemical properties of TB surface through the chemical activation with CaCl2 (CTB) and FeCl3 (FTB) were helpful in the adsorption capacities of PO43− (equilibrium adsorption capacity: FTB (1.655 mg g−1) > CTB (0.354 mg g−1) > TB (0.104 mg g−1)). The adsorption kinetics results revealed that PO43− removal by TB, CTB, and FTB was well fitted with the pseudo-second-order model (R2 = 0.999) than the pseudo-first-order model (R2 ≥ 0.929). The adsorption isotherm models showed that the Freundlich equation was suitable for PO43− removal by TB (R2 = 0.975) and CTB (R2 = 0.955). In contrast, the Langmuir equation was proper for PO43− removal by FTB (R2 = 0.987). The PO43− removal efficiency of CTB and FTB decreased with the ionic strength increased due to the compression of the electrical double layer on the CTB and FTB surfaces. Besides, the PO43− adsorptions by TB, CTB, and FTB were spontaneous endothermic reactions. These findings demonstrated FTB was the most promising method for removing PO43− in waters.

Facile Method To Synthesize Mesoporous Multimetal Oxides (ATiO3, A = Sr, Ba) with Large Specific Surface Areas and Crystalline Pore walls

2010 ◽  
Vol 22 (4) ◽  
pp. 1276-1278 ◽  
Author(s):  
Xiaoxing Fan ◽  
Ying Wang ◽  
Xinyi Chen ◽  
Ling Gao ◽  
Wenjun Luo ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Areas ◽  
Specific Surface Areas

Structure, Activity and Composition of Biofilms

1994 ◽  
Vol 29 (7) ◽  
pp. 335-344 ◽  
Author(s):  
Tian C. Zhang ◽  
Paul L. Bishop
Keyword(s):  
Dye Adsorption ◽  
Effective Diffusivity ◽  
Synthetic Wastewater ◽  
Bulk Solution ◽  
Plate Count ◽  
Spatial Distributions ◽  
Bacterial Populations ◽  
Surface Areas ◽  
Population Distributions ◽  
Micro Slicing

The spatial distributions of properties of biofilms have been investigated by using three different kinds of biofilms as test materials. Biofilms, cultured by laboratory-scale rotating drum biofilm reactors with synthetic wastewater, were first cut into 10 to 20 µm thick slices using a microtome, and then apportioned into samples representing 3 or 4 layers. The biofilm properties of each layer were investigated by measuring the densities, phospholipid concentrations, and AR18 dye adsorption abilities. The bacterial population distributions and the metabolically active bacterial distributions were studied by plate count methods or a MPN method, and the tetrazolium dye (INT) reduction method, respectively. Based on statistic evaluations, the micro-slicing technique, the procedure for analyzing phospholipid concentrations of biofilms, and the AR18 dye adsorption tests were suitable to be used in biofilm studies. It was found that the densities of biofilms in the bottom layers were 4 to 7 times higher than those in the top layers. For thick biofilms (thickness > 500 µm), the INT active bacteria decreased from 82-89% in the top layers to 5-11% in the bottom layers. The porosities of thick biofilms changed from 83-92% in the top layers to 56-64% in the bottom layers. For thin biofilms (thickness < 500 µm), the porosities of biofilms changed from 72-75% in the top layers to 35-44% in the bottom layers. Highly spatial distributions of bacterial populations, mean pore radius, and specific surface areas were also observed. As a result of these spatial distributions, the ratio of effective diffusivity to diffusivity in the bulk solution also shows a decrease with depth of the biofilm. Assuming biofilm properties are of a uniform distribution may be an over-simplified assumption, valid only in specific cases.

Carbon Microspheres Prepared by High Internal Phase Emulsion Polymerization

2011 ◽  
Vol 239-242 ◽  
pp. 3105-3108
Author(s):  
Ming Xian Liu ◽  
Li Hua Gan ◽  
Jun Hu ◽  
Hong Lai Liu ◽  
Long Wu Chen
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Aqueous Phase ◽  
Apparent Density ◽  
Tween 80 ◽  
Carbon Microspheres ◽  
High Internal Phase Emulsion ◽  
Surface Areas ◽  
Internal Phase ◽  
Specific Surface Areas

In this paper, we present a novel approach for the synthesis of carbon microspheres via the polymerization of a high internal phase emulsion (HIPE). By using Span 80 and Tween 80 as emulsifiers, 1iquid paraffin as oil phase, and the mixture of resorcinol/formaldehyde (R/F) solution as aqueous phase, an O/W emulsion was obtained. This emulsion phase inverted to a W/O HIPE induced by ammonia which served as the polymerization catalyst. Carbon microspheres (CMs) were prepared by polymerization of the HIPE, followed by drying and carbonization. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) analyzer were used to characterize as-prepared CMs. The results indicate that, in case of 0.25 wt% ammonia of the HIPE, the diameters of CMs decreased from about 2 to 1 μm when the mass fraction of aqueous R/F decreased from 0.714 to 0.357; the apparent density and the specific surface areas of the CMs, however, did not change obviously, which are about 0.6 g/cm3and 200 m2/g, respectively. The dosage of ammonia has a significant influence on the morphology and properties of CMs. With increasing of the ammonia mass to 1 wt% of the HIPE, the resultant carbon materials comprise not only CMs, but also some carbon sheets; the apparent density of which increased to 0.9 g/cm3and the specific surface areas of which decreased to below 100 m2/g. In addition, the other parameters for CMs preparation were also investigated. It was found that the proper conditions were controlling the temperature of 303-333 K and the oil/aqueous phase mass ratio of 2.5:7.

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