scholarly journals The Combination of MoS2/WO3 and Its Adsorption Properties of Methylene Blue at Low Temperatures

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 2 ◽  
Author(s):  
Yifan Zheng ◽  
Jingjing Wang ◽  
Yedan Wang ◽  
Huan Zhou ◽  
Zhiying Pu ◽  
...  

It was found previously that neither monomer MoS2 nor WO3 is an ideal material for the adsorption of organic dyes, while MoS2/WO3 composites synthesized by a two-step hydrothermal method have outstanding adsorption effects. In this work, the chemical state of each element was found to be changed after combination by X-ray photoelectron spectroscopy analysis, which lead to their differences in adsorption performance. Moreover, the adsorption test of methylene blue on MoS2/WO3 composites was carried out under a series of temperatures, showing that the prepared composites also had appreciable adsorption rates at lower temperatures. The adsorption process could be well described by the Freundlich isothermal model and the pseudo-second order model. In addition, the particle-internal diffusion model simulation revealed that the internal diffusion of the particles played an important role in the whole adsorption process.

2017 ◽  
Vol 77 (1) ◽  
pp. 167-176 ◽  
Author(s):  
Weisheng Zheng ◽  
Hailing Wang ◽  
Zhaolian Zhu ◽  
Peng Wei

Abstract Polydopamine-modified granule organo-attapulgite adsorbent (PDA-GOAT) was facilely prepared via a dip-coating approach. The samples were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Surface area and pore size were calculated from the Brunauer–Emmett–Teller method by N2 adsorption–desorption isotherm. The adsorption behaviour of methylene blue (MB) onto PDA-GOAT was systematically investigated. The experimental data revealed that the adsorption process fitted well with the pseudo-second-order kinetics equation and the adsorption isotherm fitted better with the Langmuir model. Thermodynamic analyses illustrated that MB adsorption onto PDA-GOAT was a physisorption endothermic process. Importantly, PDA-GOAT can be regenerated by NaBH4 aqueous solution. The obtained results prove that PDA-GOAT can be a superior reusable adsorbent for the removal of MB from effluent.


2021 ◽  
Author(s):  
Ran Chen ◽  
Junjun Wang ◽  
Ling Fan ◽  
Linlin Cui ◽  
Yejuan Zhang ◽  
...  

Abstract To solve the problem of harvesting microalgae during heavy metal adsorption, six different carriers were selected in this study to compare the adsorption behavior of microalgae after immobilization. The optimal immobilized carrier-chitosan was obtained under the following conditions of chitosan: acetic acid (2:40), microalgae concentration (10 8 cells/mL), and immobilization time (18 h). The optimal adsorption conditions were as follows: temperature: 30°C, pH: 5.0, adsorption dose: 1.5 g/L, initial ion concentration: 40 mg/L. Fourier transform infrared spectroscopy analysis showed that the specific functional groups of the specific microalgae played an important role in the adsorption process. The kinetic and isothermal model data showed that the adsorption process was mainly chemical adsorption and homogeneous monolayer adsorption. Moreover, X-ray photoelectron spectroscopy analysis showed that the Cr adsorption process involves the reduction of Cr(VI) to Cr(III).


2021 ◽  
Vol 10 (1) ◽  
pp. 59-66
Author(s):  
Son Le Lam ◽  
Phu Nguyen Vinh ◽  
Hieu Le Trung ◽  
Tan Le Thua ◽  
Nhan Dang Thi Thanh ◽  
...  

Glucomannan/graphene oxide (GM/GO) hydrogel was synthesized by using calcium hydroxide as the crosslinker. The synthesized material was characterized by using IR, XRD, SEM, EDX and RAMAN technology. The composite hydrogel was used for removal of organic dyes from aqueous solution. The results showed that the GM/GO hydrogel had a porous structure and a high adsorption capacity toward methylene blue (MB). The pseudo-second-order kinetic model could fit the rate equation of MB adsorption onto the GM/GO hydrogel. The adsorption of MB onto GM/GO hydrogel was a spontaneous process. In addition, the equilibrium adsorption isotherm data indicated that equilibrium data were fitted to the Langmuir isotherm and the maximum dye adsorption capacity was 198,69 mg.g-1. Moreover, the hydrogel was stable and easily recovered and adsorption capacity was around 97% of the initial saturation adsorption capacity after being used five times.


NANO ◽  
2021 ◽  
pp. 2150068
Author(s):  
Zhao Yang ◽  
Zhongwei Zhao ◽  
Xuan Yang ◽  
Zongli Ren

For the treatment of dye wastewater, it is of great significance to develop new adsorbents with high adsorption capacity and good separation effect. In this study, the Fe-Co magnetic activated carbon material (CN-Fe-Co-AC) was first prepared by high-temperature calcination. CN-Fe-Co-AC is physically characterized by various methods. CN-Fe-Co-AC can efficiently and quickly remove the organic dyes methylene blue (MB) and acid blue 80 (AB80). The adsorption of MB and acid blue based on CN-Fe-Co-AC adsorbent is mainly through the specific surface area and the functional groups on the surface. During this recovery process, the adsorption activity of CN-Fe-Co-AC for MB and AB80 decreased slightly. Kinetic data can be described using a Pseudo-second-order model and the data for adsorption equilibrium can be described using the Langmuir isotherm. The theoretical adsorption capacities of MB and AB80 are 104.82[Formula: see text]mg/g and 26.94[Formula: see text]mg/g, respectively. After repeated use of five times, the removal rate of MB exceeded 96%, and the removal rate of AB80 exceeded 75%. The excellent adsorption performance and recyclability of CN-Fe-Co-AC indicate that this material has certain potential application value.


2019 ◽  
Vol 79 (4) ◽  
pp. 676-687 ◽  
Author(s):  
Zou Junyu ◽  
Song Zefeng ◽  
Yang Yuesuo

Abstract Preparation of sludge-derived mesoporous carbon materials (SMCs) through pyrolysis of excess activated sludge from urban municipal sewage plants is an effective means of reducing pollution and utilizing a waste resource. This paper presented a method of SMC preparation in which calcium oxide (CaO), polyacrylamide (PAM), and chitosan (CAS) flocculating agents were used as pore-forming additives. Physical and chemical characterizations of the prepared SMCs were conducted by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). The prepared SMCs were used to adsorb a tetracycline (TC) antibiotic pollutant. The influences of pH, adsorption time, temperature, and pollutant concentration on TC adsorption capacity were determined. The experiments demonstrated that weakly acidic conditions were conducive to TC adsorption, which mainly occurs via electrostatic and π-π interactions. The TC adsorption process by SMCs conformed better to the pseudo-second-order models, indicating that chemical adsorption was the dominant adsorption process. The isothermal adsorption of TC by the SMCs conformed to the Freundlich model. This implied that TC easily adhered onto the SMC surfaces via multilayer homogeneous adsorption. Thermodynamic studies revealed that the adsorption of TC onto SMCs was spontaneous and endothermic.


Author(s):  
Muhammad Muhammad ◽  
Meriatna Meriatna ◽  
Nia Afriani ◽  
Rizka Mulyawan

In this study, Oyster (Crassostrea gigas) shell powder which contains calcium carbonate (CaCO3) was converted into calcium oxide (CaO). The Oyster shell powder that had been activated was utilized for the adsorption of the methylene blue (MB) dyeing material, which is one of waste water concerns. Oyster shells were crushed and sieved into 100 mesh sized powder and then calcinated at a temperature of 600℃ and 800℃ both for 4 hours period. To determine the adsorption equilibrium, methylene blue (MB) solution was used with varying concentration from 10 to 50 mg/L in which the adsorbent weighing 3 g was put into a conical flash and shaken until the adsorption equilibrium was reached. As for the adsorption kinetics, 250 mL MB solution was used with initial concentrations of 10, 20 and 30 mg/L, with an adsorbent weight of 3 g and a solution at pH 11 for each concentration. The evaluation of the experimental data from the adsorption process is well explained by the Freundlich equation, with the correlation coefficient value (R2) found to be 0.9999, where the value of the adsorption intensity (n) is close to unity; this shows that the adsorption is multilayer or in other words the adsorption energy is heterogeneous. The kinetics study also shows that pseudo second-order model is the most applicable to the adsorption process. From the pseudo-second-order model, with the correlation coefficient between 0.9984 - 0.9999 can explain that the methylene blue (MB) adsorption process is chemically based sorption or in other words termed as chemisorption.


2022 ◽  
Author(s):  
Chuqing Yao ◽  
Yaodong Dai ◽  
Shuquan Chang ◽  
Haiqian Zhang

Abstract In this work, novel Prussian blue tetragonal nanorods were prepared by template-free solvothermal methods for removal of radionuclide Cs and Sr. It was worth that Prussian blue nanorods exhibited the better adsorption performance than co-precipitation PB or Prussian blue analogue composites. Thermodynamic analysis implied that adsorption process was spontaneous and endothermic which was described well with Langmuir isotherm and pseudo-second-order equation, the maximum adsorption capacity of PB nanorod was estimated to be 194.26 mg g-1 and 256.62 mg g-1 for Cs+ and Sr2+. The adsorption mechanism of Cs+ and Sr2+ was studied by X-ray photoelectron spectroscopy, X-ray diffraction and 57Fe Mössbaure spectroscopy, the results revealed that Cs+ entered in PB crystal to generate a new phase, the most of Sr2+ was trapped in internal crystal and the other exchanged Fe2+. Furthermore, the effect of co-existing ions and pH for PB adsorption process were also investigated. The results suggest that PB nanorods were outstanding candidate for removal of Cs+ and Sr2+ from radioactive wastewater.


2018 ◽  
Vol 7 (3) ◽  
pp. 204-216
Author(s):  
Lamya Kadiri ◽  
Abdelkarim Ouass ◽  
Youness Essaadaoui ◽  
El Housseine Rifi ◽  
Ahmed Lebkiri

Coriandrum sativum seeds (CSS) were investigated as a new eco-friendly and economic biosorbent for the removal of methylene blue (MB) dye from synthetic solutions. First, the spectroscopic analyses were effectuated using FTIR and SEM to confirm the possibility of CSS to remove MB dye from aqueous solutions. The study of the influence of different parameters, such as contact time, CSS mass, solution pH, MB concentration, and temperature was realized and proved the rapid and efficient power adopted by CSS as a removal of the studied dye. Also, the regeneration study was effectuated for four cycles with excellent adsorption rates. The modeling studies revealed that the studied process obeys the pseudo-second-order model and Langmuir isotherm model. The adsorption amount was found to be 107.53 mg/g. Finally, the determination of thermodynamic parameters indicated the exothermic and spontaneous type of the removal process of MB onto CSS.


Author(s):  
Atyaf Khalid Hameed ◽  
Nugroho Dewayanto ◽  
Du Dongyun ◽  
Mohd Ridzuan Nordin ◽  
Mohd Hasbi Ab Rahim

<p>Zero valent iron supported on mesoporous silicanano particles (NZVI/MSNs) was prepared by the aqueous phase borohydride reduction methods. Prior to the reduction, mesoporous silica nanoparticles (MSNs) were prepared through the activation of fumed silica with concentrated HCl by refluxing at 90 °C. FTIR, XRD, FESEM, EDX and BET were used to characterize theadsorbents prepared. BET surface areas of MSNs, NZVI, and NZVI/MSNs were 126, 41, and 72 m<sup>2</sup>/g for, respectively. The performance of NZVI/MSNs as adsorbent was examined by adsorption of methylene blue (MB), performed in series of batch experiments. In the kinetic studies, pseudo first order and pseudo second order kinetic models were examined. The pseudo second order equation provided the best fit with the experimental data. Thermodynamic studies indicated that the adsorption process is endothermic with ΔH° was 90.53 kJ/mol. Positive ΔS° (300 J/mol) and negative ΔG° (-6.42 kJ/mol) was recorded, indicating the spontaneous of the adsorption process and naturally favorable. Copyright © 2016 BCREC GROUP. All rights reserved</p><p><em>Received: 5<sup>th</sup> March 2016; Revised: 18<sup>th</sup> March 2016; Accepted: 18<sup>th</sup> March 2016</em></p><p><strong>How to Cite:</strong> Hameed, A.K., Dewayanto, N., Dongyun, D., Nordin, M.R., Mohd Hasbi Ab. Rahim, M.H.A. (2016). Kinetic and Thermodynamics of Methylene Blue Adsorption onto Zero Valent Iron Supported on Mesoporous Silica.<em> Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11 (2): 250-261 (doi:10.9767/bcrec.11.2.443.250-261)</p><p><strong>Permalink/DOI:</strong> http://dx.doi.org/10.9767/bcrec.11.2.443.250-261</p>


2020 ◽  
Vol 81 (6) ◽  
pp. 1180-1190
Author(s):  
You Wang ◽  
Qifan Peng ◽  
Naseem Akhtar ◽  
Xiaonong Chen ◽  
Yaqin Huang

Abstract Microporous fish waste-based activated carbon material (MFC) was prepared, with a large surface area of 2,193.52 m²/g, a pore size of 2.67 nm and micropore and total pore volumes of 0.9168 cm³/g and 0.9975 cm³/g, respectively. Adsorption efficiency of MFC was investigated by removal of methylene blue dye from wastewater. The Langmuir model and pseudo-second-order kinetics adequately described the adsorption process. MFC exhibited a high adsorption capacity of 476.19 mg/g at 30 °C, and reached equilibrium within 1 h. MFC could be an efficient and low-cost adsorbent for cationic dye removal during wastewater treatment.


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