Enhanced nitrogen adsorption capacity on Ca2+ ion-exchanged hierarchical X zeolite

2021 ◽  
Vol 264 ◽  
pp. 118442
Author(s):  
Hadis Mousavi ◽  
Jafar Towfighi Darian ◽  
Babak Mokhtarani
2014 ◽  
Vol 1053 ◽  
pp. 303-310 ◽  
Author(s):  
Mian Wu Meng ◽  
Cong Liang Qi ◽  
Qing Ye Liu ◽  
Liang Lv ◽  
Hao Ai ◽  
...  

A three-factor-three-level experiment was developed by the central composite design (CCD) and Response surface methodology to discuss the effects of concentration of K2CO3, activation temperature and time on the adsorption capacity of the activated carbon (AC) derived from the rice husk and to identify the key preparation parameters. The performance of the AC was characterized by nitrogen adsorption isotherm as Brunauer–Emmett–Teller (BET) and scanning electron microscope (SEM), respectively. The optimal parameters were obtained: Rice husk was soaked in K2CO3 solution (2.32 mol/L) with an impregnation ratio (rice husk: K2CO3=1:3) (wt. %), activated at 1239 K for 0.48 h. The results showed that iodine adsorption capacity of the AC was 1268.52 mg/g, the error between the models predicted (1356.98 mg/g) was only 6.2%. The AC has a large apparent surface area (SBET = 1312 m2/g), total pore volume (0.78 cm3/g) and average pore diameter (11.92 Å).


Zeolites ◽  
1995 ◽  
Vol 15 (1) ◽  
pp. 85
Author(s):  
C.G. Coe ◽  
J.F. Kirner ◽  
R. Pierantozzi

2018 ◽  
Vol 775 ◽  
pp. 376-382 ◽  
Author(s):  
Alzhan Baimenov ◽  
Dmitriy Berillo ◽  
Leila Abylgazina ◽  
Stavros G. Poulopoulos ◽  
Vassilis J. Inglezakis

In this work, amphoteric cryogels based on N,N-dimethyl acrylamide, methacrylic acid and allylamine, crosslinked by N,N-methylenebisacrylamide were synthesized by free-radical polymerization in cryo-conditions. The synthesized cryogels were used for the removal of cadmium ions from aqueous solutions under different pH values. The chemical structure was studied by FTIR, porosity by nitrogen adsorption and morphology by scanning electron microscopy and texture analyzer. The amphoteric properties of cryogels were studied by zeta potential measurements. Adsorption tests revealed that cryogels exhibit 3 times higher adsorption capacity at pH 6.0 than at pH 4.0. The maximum adsorption capacity of the amphoteric cryogels for Cd2+ was 113 mg/g, at pH 6.0 and initial Cd2+ concentration 100 ppm. The results suggest that the predominant removal mechanism is ion exchange between sodium, which initially presents in the structure of the cryogel, and cadmium from the aqueous phase. Recovery studies suggested that the cryogels used can be regenerated and efficiently reused.


2014 ◽  
Vol 68 (1) ◽  
Author(s):  
Huan Huang ◽  
De-Zhi Yi ◽  
Yan-Nan Lu ◽  
Xiao-Lin Wu ◽  
Yun-Peng Bai ◽  
...  

AbstractSamples of activated bentonite and activated bentonite modified with CuCl and CuCl2, separately, were tested as dimethyl sulfide (DMS) adsorbents. The adsorption and desorption behaviours of DMS on the adsorbents were studied systematically. The adsorbents were characterised by nitrogen adsorption, XRD, and DMS-TPD tests. The addition of CuCl and CuCl2 to the activated carbon significantly enhanced the adsorption capacity of DMS, despite a notable decrease in the specific surface area and total pore volume of the activated bentonite. It is presumed that copper cation species may act as an adsorption site for DMS. The adsorption capacity of Cu(II)-bentonite was better than that of Cu(I)-bentonite. The DMS-TPD patterns indicate that the stronger electrophilicity of Cu(II) compared to that of Cu(I) caused it to interact with the DMS molecules more strongly, thus contributing to a better adsorptive performance. The Cu(II)-bentonite calcined at 150°C had the best DMS removal performance with a high sulphur capacity of 70.56 mg S g−1 adsorbent. The DMS removal performance became much lower with the increase in the calcination temperature, which appeared to be due to the decrease in the CuCl2·2H2O phase and the formation of the monoclinic Cu(OH)Cl phase.


2021 ◽  
Author(s):  
You Wu ◽  
Zuannian Liu ◽  
Bakhtari Mohammad Fahim ◽  
Junnan Luo

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.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Xun Zhao ◽  
Tao Feng ◽  
Ping Wang ◽  
Ze Liao

In order to grasp the effect of soft and hard coal pore structure on gas adsorption characteristics, based on fractal geometry theory, low-temperature nitrogen adsorption and constant temperature adsorption test methods are used to test the pore structure characteristics of soft coal and its influence on gas adsorption characteristics. We used box dimension algorithm to measure the fractal dimension and distribution of coal sample microstructure. The research results show that the initial nitrogen adsorption capacity of soft coal is greater than that of hard coal, and the adsorption hysteresis loop of soft coal is more obvious than that of hard coal. And the adsorption curve rises faster in the high relative pressure section. The specific surface area and pore volume of soft coal are larger than those of hard coal. The number of pores is much larger than that of hard coal. In particular, the superposition of the adsorption force field in the micropores and the diffusion in the mesopores enhance the adsorption potential of soft coal. Introducing the concept of adsorption residence time, it is concluded that more adsorption sites on the surface of soft coal make the adsorption and residence time of gas on the surface of soft coal longer. Fractal characteristics of the soft coal surface are more obvious. The saturated adsorption capacity of soft coal and the rate of reaching saturation adsorption are both greater than those of hard coal. The research results of this manuscript will provide a theoretical basis for in-depth analysis of the adsorption/desorption mechanism of coalbed methane in soft coal seams and the formulation of practical coalbed methane control measures.


2019 ◽  
Vol 9 (22) ◽  
pp. 4856 ◽  
Author(s):  
Marwa El-Azazy ◽  
Sarra Dimassi ◽  
Ahmed El-Shafie ◽  
Ahmed Issa

Titan yellow (TY), a triazene azo dye, was removed from contaminated wastewater samples using a green adsorbent recycled from Aloe vera leaves (AV) waste. Two adsorbents were developed—air-dried Aloe vera (ADAV) and thermally treated Aloe vera (TTAV). Adsorption efficacy of both adsorbents was assessed in terms of percent removal (%R) of TY and adsorption capacity (qe). ADAV had a better performance compared to TTAV. Plackett–Burman design (PBD) was exploited to establish the experimental pattern of the study. Four variables were studied: pH, adsorbent dose (AD), dye concentration (DC), and stirring time (ST). Analysis of variance (ANOVA) at 95.0 confidence interval (CI), control, and quality charts helped establish regression model(s). Characterization of both adsorbents was performed using FT-IR/Raman spectroscopy together with TGA/dTGA and SEM/energy dispersive X-ray spectroscopy (EDX) analyses. Textural properties were determined using nitrogen adsorption isotherms at 77 K. Results showed that the surface areas of ADAV and TTAV300 were 3.940 and 7.076 m2/g, respectively. Raman analysis showed that the TTAV had clear D- and G-bands. Equilibrium studies revealed that data were well fitted to Freundlich isotherm with a maximum adsorption capacity of 55.25 mg/g using Langmuir equation, and the adsorption was physisorption. Adsorption followed a pseudo-second order that occurred in two steps—diffusion and then adsorption.


2018 ◽  
Vol 67 ◽  
pp. 03019 ◽  
Author(s):  
Yuliusman ◽  
Nasruddin ◽  
Yugo WidhiNugroho ◽  
Hizba IlmiNaf’an ◽  
Jervis Sinto

Adsorbed natural gas (ANG) can be developed through its porous adsorbent, especially activated carbon (AC) which has larger specific surface area. AC made of soybean straw is developed because of its abundance as agricultural waste in Indonesia and high lignocellulosic content. AC is produced in 500°C furnace for 1 hour with nitrogen gas flow of 200 mL/minute. For AC production, variations of chemical activating agents utilizing ZnCl2 and KOH and the concentration NiO as modification substance are made in this paper. Characterizations are made through iodine number, SEM, EDX, and nitrogen adsorption-desorption for obtaining data of adsorption capacity, surface topography, main composition, and particles specification. ZnCl2 activated carbon shows better result with iodine number of 577.73 mg/g and SBET of 741.26 m2/g, and the second-best is found in 2%-NiO-modified ZnCl2 activated carbon with iodine number of 534.79 mg/g and SBET of 632.24 m2/g. It is concluded that development of soybean straw as activated carbon precursor is still needed to obtain larger SBETand better adsorption capacity.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3859
Author(s):  
Katarzyna Jedynak ◽  
Barbara Charmas

In this study the pyrolysis of Norway spruce cones, a lignocellulosic biomass was made. The biochar product was obtained by means of the physical activation method. CO2 was used as the activating gas. The surface properties of biochars were characterized by the nitrogen adsorption/desorption isotherms, scanning electron microscopy (SEM/EDS), X-ray fluorescence energy dispersion spectroscopy (ED-XRF), thermal analysis (TGA/DTA), infrared spectroscopy (ATR FT-IR), Raman spectroscopy and the Boehm’s titration method as well as the point of zero charge (pHpzc). The adsorption capacity and the possibility of ammonia desorption (TPD) were also examined. It has been shown that spruce cones can be successfully used as a cheap precursor of well-developed surface biochars, characterized by a large pore volume and good sorption properties. All obtained activated biochars exhibit a largely microporous structure and an acidic character surface. The investigated activated materials have the specific surface areas from 112 to 1181 m2 g−1. The maximum NH3 adsorption capacity of the activated biochar was determined to be 5.18 mg g−1 (88.22 mmol g−1) at 0 °C. These results indicate the applicability of spruce cones as a cheap precursor for the sustainable production of the cost-effective and environmentally friendly biochar adsorbent.


2018 ◽  
Vol 47 (5) ◽  
pp. 406-414 ◽  
Author(s):  
Yi Liu ◽  
Hao Wang ◽  
Yongfeng Liu ◽  
Meng Shi ◽  
Duolong Di

PurposeThe purpose of this paper is to focus on the selection of the optimum porous material modified with poly-dopamine coating for peptides enrichment. The adsorption behaviors for peptides and the antioxidant capacity of peptides fraction purified by the porous materials were investigated.Design/methodology/approachThe optimum porous material with the highest adsorption capacity for peptides was selected for surface modification. The surface modified porous material was characterized by SEM, nitrogen adsorption-desorption isotherm and color change.FindingsThe results showed that the porous material was successfully modified with poly-dopamine coating. Adsorption capacity for peptides of the modified porous material was enhanced compared to the original porous material. Antioxidant capacity of peptides fraction enriched by the modified porous material was much higher than that enriched by the original porous material, indicating that the introduction of poly-dopamine coating was inclined to enrich peptides with certain amino acid residues.Research limitations/implicationsThe structures of peptides are a bit not clear, which is the subject of future investigation.Practical implicationsThis contribution provides a method to design and prepare porous materials with poly-dopamine coating to separate and enrich peptides or peptides fraction with high antioxidant capacity.Originality/valueIt showed that polarity, surface area, pore diameter and interactions were contributed to high adsorption capacity. The peptides fraction purified by the modified porous material showed excellent antioxidant capacity through results of reduction of DPPH radical, because of the enrichment of the peptides with certain amino acids residues which were considered to enhance radical scavenging capacity. This paper provides new insights into designing and preparing porous materials with poly-dopamine coating to enrich peptides fraction with high antioxidant capacity.


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