scholarly journals Effect of synthesis conditions  on  methylene blue adsorption capacity of electrochemically preparated graphene

2020 ◽  
Vol 9 (3) ◽  
pp. 9-14
Author(s):  
Hao Pham Van ◽  
Linh Ha Xuan ◽  
Oanh Phung Thi ◽  
Hong Phan Ngoc ◽  
Huy Nguyen Nhat ◽  
...  

This report presents the effect of synthesis conditions on the synthesis of graphene nanosheets via electrochemical exfoliation method for adsorbing methylene blue from aqueous solution. Oxygen-containing functional groups and defects in the material were characterized by Raman and X-ray photoelectron spectroscopy (XPS). As a result, by using voltage of 15 V, (NH4)2SO4 (5%, 250 mL) and KOH (7.5%, 250 mL), the obtained material showed the highest MB adsorption capacity due to the high densities of oxygen-containing groups and defects comparison to other conditions.

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Hui-qiang Wang ◽  
Ming-hua Liu ◽  
Xin Luo ◽  
Yi-fan Liu ◽  
Fei-er Chen ◽  
...  

ZnFe2O4/AC composites were prepared by the one-pot hydrothermal method using the activated carbon (AC) as a carrier. The synthesis conditions were optimized by a single-factor experiment. The structural, textural, and surface properties of the adsorbent have been comprehensively characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, Brunauer–Emmett–Teller (BET) measurements, and X-ray photoelectron spectroscopy (XPS) analysis. The SO2 removal capacities of the composites were investigated via testing the adsorption capacity at the self-made desulfurization equipment. The results show that the adsorption capacity of ZnFe2O4/AC composites is much higher than that of the AC and ZnFe2O4 samples, respectively. The composite overcomes the disadvantages of the traditional sintering, showing a very high desulfurization performance. The breakthrough time was 147 min, and the sulfur adsorption capacity could reach 23.67% in the desulfurization performance test.


2019 ◽  
Vol 37 (3-4) ◽  
pp. 312-332 ◽  
Author(s):  
Qi-Xia Liu ◽  
Yi-Ru Zhou ◽  
Mei Wang ◽  
Qian Zhang ◽  
Tao Ji ◽  
...  

Two viscose-based activated carbon fiber felts (VACFF-1300 and VACFF-1600) with different specific surface areas and pore structures were prepared via two-step carbonization and steam activation and characterized by SEM observation, N2 adsorption/desorption isotherms, Fourier-transform infrared, X-ray diffraction and X-ray photoelectron spectroscopy analysis. They were used as adsorbents for the removal of methylene blue dye from aqueous solution, and the adsorption equilibrium and kinetics were studied via batch adsorption experiments and the adsorption mechanisms were investigated. Results showed that the equilibrium data for methylene blue adsorption onto VACFF-1300 and VACFF-1600 fitted well to the Langmuir isotherm model, with maximum monolayer adsorption capacity of 256.1 mg/g and 325.8 mg/g, respectively. Besides, the adsorption kinetics study showed that the adsorption of methylene blue onto the two VACFF samples could be best described by the pseudo second-order model. Moreover, the intraparticle diffusion modelling showed that intraparticle diffusion is rate-controlling for both VACFF-1300 and VACFF-1600, and external diffusion is also a rate-controlling step for the latter.


Inorganics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Jennifer Shankwitz ◽  
Daniel Speed ◽  
Dillon Sinanan ◽  
Greg Szulczewski

The adsorption of benzene, toluene, ethylbenzene, and xylene isomers, also known as BTEX, from the gas phase into porous thin films of the metal–organic framework UiO-66-X, where X = H, NH2, and NO2, was measured to quantify adsorption capacity. The thin films were grown by a vapor-conversion method onto Au-coated quartz microbalance crystals. The MOF thin films were characterized by IR and Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The thin films were activated by heating under high vacuum and exposed to each gas to calculate the Henry’s constant. The results demonstrate that the functional groups in the organic linker and missing-linkers both play important roles in the adsorption capacity. Several trends can be observed in the data. First, all the compounds in the BTEX family have lower Henry’s constants in the UiO-66-H films compared to the UiO-66-NH2 and UiO-66-NO2 films, which can largely be attributed to the absence of a functional group on the linker. Second, at 25 °C, the Henry’s constants for all the BTEX compounds in UiO-66-NO2 films are larger than UiO-66-NH2 films. Third, the role of missing linkers is addressed by comparing the measured adsorption capacity to ideal pore filling. The results show that the UiO-66-H films are the most defect-free and the UiO-66-NO2 films have the most missing linker defects.


2020 ◽  

<p>Composite based Ca/Al layered double hydroxide and biochar was prepared using mixing coprecipitation method at pH 10. Composite and the starting materials was characterized using X-ray, FTIR, BET, thermal, and SEM-EDX analyses. Furthermore, composite was used as adsorbent of methylene blue from aqueous solution. Several factors that influencing the adsorption process was investigated such as adsorption time, initial concentration, and temperature adsorption. The performance of composite as adsorbent was evaluated by reusability process. The results showed that composite has diffraction peak at 9.82, 17.99, 19.86, 20.55, 29.32, 30.95, 32.65, 36.61, 37.00, 43.49, 47.15, 55.12, and 56.12 deg, which was based on diffraction of Ca/Al layered double hydroxide and biochar as starting materials. The surface area of composite was 158.291 m2/g and largely higher than starting materials. The morphology of composite also shows regularity shape than Ca/Al layered double hydroxide and biochar. Adsorption of methylene blue on composite showed that higher adsorption capacity (32.535 mg/g) than starting materials. The reusability of adsorbent showed that composite can be used several times ad adsorbent without loss adsorption capacity and these phenomena indicated composite is excellent material to remove dye from aqueous solution.</p>


2013 ◽  
Vol 61 (2) ◽  
pp. 193-198 ◽  
Author(s):  
Hosne Ara Begum ◽  
Mohammad Khalid Bin Mahbub

The adsorptive properties of carboxymethyl cellulose (CMC) prepared from sugarcane bagasse (SB) for the removal of methylene blue (MB) from aqueous solution was investigated. Two batches of CMC, CTSB-CMC-B1 and CTSB-CMC-B2, were prepared from chlorite treated sugarcane bagasse (CTSB). The prepared CMCs were characterized by FT-IR spectral analysis. Degree of substitution (DS) value of prepared CMCs was estimated. Batch adsorption experiments show that the adsorption of MB on CMCs reaches equilibrium within 30 minutes. The MB adsorption capacity of CTSB-CMC-B1 and CTSB-CMC-B2 were found to be 652.0 and 369.0 mg g?1, respectively. CMC with the higher DS value (CTSBCMC- B1) shows higher adsorption capacity than the CMC having lower DS value (CTSB-CMC-B2). The uptake of MB was minimum at pH 2 and gradually increases with the increase of pH. From the desorption studies, it was found that large amount of MB was released in strong acidic (pH 3.0) conditions. DOI: http://dx.doi.org/10.3329/dujs.v61i2.17069 Dhaka Univ. J. Sci. 61(2): 193-198, 2013 (July)


Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 661
Author(s):  
Zhiwei Ying ◽  
Xinwei Chen ◽  
He Li ◽  
Xinqi Liu ◽  
Chi Zhang ◽  
...  

Soybean dreg is a by-product of soybean products production, with a large consumption in China. Low utilization value leads to random discarding, which is one of the important sources of urban pollution. In this work, porous biochar was synthesized using a one-pot method and potassium bicarbonate (KHCO3) with low-cost soybean dreg (SD) powder as the carbon precursor to investigating the adsorption of methylene blue (MB). The prepared samples were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental analyzer (EA), Brunauer-Emmett-Teller (BET), X-ray diffractometer (XRD), Raman spectroscopy (Raman), Fourier transform infrared spectrometer (FTIR), and X-ray photoelectron spectroscopy (XPS). The obtained SDB-K-3 showed a high specific surface area of 1620 m2 g−1, a large pore volume of 0.7509 cm3 g−1, and an average pore diameter of 1.859 nm. The results indicated that the maximum adsorption capacity of SDB-K-3 to MB could reach 1273.51 mg g−1 at 318 K. The kinetic data were most consistent with the pseudo-second-order model and the adsorption behavior was more suitable for the Langmuir isotherm equation. This study demonstrated that the porous biochar adsorbent can be prepared from soybean dreg by high value utilization, and it could hold significant potential for dye wastewater treatment in the future.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 558
Author(s):  
Wenhui Zhu ◽  
Caiyun Zhang ◽  
Yali Chen ◽  
Qiliang Deng

Photothermal materials are attracting more and more attention. In this research, we synthesized a ferrocene-containing polymer with magnetism and photothermal properties. The resulting polymer was characterized by Fourier-transform infrared (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Its photo-thermocatalytic activity was investigated by choosing methylene blue (MB) as a model compound. The degradation percent of MB under an irradiated 808 nm laser reaches 99.5% within 15 min, and the degradation rate is 0.5517 min−1, which is 145 times more than that of room temperature degradation. Under irradiation with simulated sunlight, the degradation rate is 0.0092 min−1, which is approximately 2.5 times more than that of room temperature degradation. The present study may open up a feasible route to degrade organic pollutants.


Author(s):  
Anwar Ameen Hezam Saeed ◽  
Noorfidza Yub Harun ◽  
Suriati Sufian ◽  
Muhammad Roil Bilad ◽  
Zaki Yamani Zakaria ◽  
...  

Development of strategies for removing heavy metals from aquatic environments is in high demand. Cadmium is one of the most dangerous metals in the environment, even under extremely low quantities. In this study, kenaf and magnetic biochar composite were prepared for the adsorption of Cd2+. The synthesized biochar was characterized using (a vibrating-sample magnetometer VSM), Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The adsorption batch study was carried out to investigate the influence of pH, kinetics, isotherm, and thermodynamics on Cd2+ adsorption. The characterization results demonstrated that the biochar contained iron particles that help in improving the textural properties (i.e., surface area and pore volume), increasing the number of oxygen-containing groups, and forming inner-sphere complexes with oxygen-containing groups. The adsorption study results show that optimum adsorption was achieved under pH 5–6. An increase in initial ion concentration and solution temperature resulted in increased adsorption capacity. Surface modification of biochar using iron oxide for imposing magnetic property allowed for easy separation by external magnet and regeneration. The magnetic biochar composite also showed a higher affinity to Cd2+ than the pristine biochar. The adsorption data fit well with the pseudo-second-order and the Langmuir isotherm, with the maximum adsorption capacity of 47.90 mg/g.


Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 942 ◽  
Author(s):  
Huo-Xi Jin ◽  
Hong Xu ◽  
Nan Wang ◽  
Li-Ye Yang ◽  
Yang-Guang Wang ◽  
...  

The ability to remove toxic heavy metals, such as Pb(II), from the environment is an important objective from both human-health and ecological perspectives. Herein, we describe the fabrication of a novel carboxymethylcellulose-coated metal organic material (MOF-5–CMC) adsorbent that removed lead ions from aqueous solutions. The adsorption material was characterized by Fourier-transform infrared spectroscopy, X-ray diffractometry, scanning electron microscopy, and X-ray photoelectron spectroscopy. We studied the functions of the contact time, pH, the original concentration of the Pb(II) solution, and adsorption temperature on adsorption capacity. MOF-5–CMC beads exhibit good adsorption performance; the maximum adsorption capacity obtained from the Langmuir isotherm-model is 322.58 mg/g, and the adsorption equilibrium was reached in 120 min at a concentration of 300 mg/L. The adsorption kinetics is well described by pseudo-second-order kinetics, and the adsorption equilibrium data are well fitted to the Langmuir isotherm model (R2 = 0.988). Thermodynamics experiments indicate that the adsorption process is both spontaneous and endothermic. In addition, the adsorbent is reusable. We conclude that MOF-5–CMC is a good adsorbent that can be used to remove Pb(II) from aqueous solutions.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Patcharanan Junploy ◽  
Titipun Thongtem ◽  
Somchai Thongtem ◽  
Anukorn Phuruangrat

SrSn(OH)6 precursors synthesized by a cyclic microwave radiation (CMR) process were calcined at 900°C for 3 h to form rod-like SrSnO3. Further, the rod-like SrSnO3 and AgNO3 in ethylene glycol (EG) were ultrasonically vibrated to form rod-like Ag/SrSnO3 composites, characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron microscopy (EM), Fourier transform infrared (FTIR) spectroscopy, and UV-visible analysis. The photocatalyses of rod-like SrSnO3, 1 wt%, 5 wt%, and 10 wt% Ag/SrSnO3 composites were studied for degradation of methylene blue (MB, C16H18N3SCl) dye under ultraviolet (UV) radiation. In this research, the 5 wt% Ag/SrSnO3 composites showed the highest activity, enhanced by the electron-hole separation process. The photoactivity became lower by the excessive Ag nanoparticles due to the negative effect caused by reduction in the absorption of UV radiation.


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