scholarly journals Synthesis of Magnetic Biochar and Their Application in the Treatment of Methylene Blue in Aqueous Solutions

Author(s):  
Tran Dinh Trinh ◽  
Nguyen Thi Hoai Phuong

Magnetic biochar materials were synthesized by heating rice husk at 500°C under nitrogen environment, then fixing iron oxides on biochar surface using hydrothermal method applied to Fe(OH)2 and Fe(OH)3 which were generated from respective precursors Fe2+ and Fe3+ in alkaline environment. The presence of iron oxides on the surface of biochar and the surface characteristics of iron-composite materials were studied with the aid of modern physicochemical analysis techniques (SEM/EDX, BET, FT-IR, XRD). Magnetic biochar materials were relatively porous, with an average spectific surface area of 62.1 m2, an average capillary size of about 17.2 nm. The mixture of iron oxide particles were revealed within the nano scale (about 15 nm). The methylene blue adsorption efficiency depended upon the amount of adsorbent, adsorption time, pH of solution and pollutant concentrations. Specifically, the optimal conditions for maximum adsorption efficiency were as follows: 0.02 g/L of magnetic biochar, the adsorption equilibrium time was 3 hours at room temperature, in a solution of pH7; The efficiency of methylene blue adsorption in optimal conditions reached over 98.82%. The Langmuir and Freundlich isotherm adsorption models all described well the methylene blue adsorption process at room temperature, with the regression coefficients R2 of 95.0 and 90.0, respectively. The maximum adsorption capacity of methylene blue calculated by Langmuir model was 22.4 mg/g.

2015 ◽  
Vol 14 (04) ◽  
pp. 1550009 ◽  
Author(s):  
N. M. Mubarak ◽  
Y. T. Fo ◽  
Hikmat Said Al-Salim ◽  
J. N. Sahu ◽  
E. C. Abdullah ◽  
...  

The study on the removal of methylene blue (MB) and orange-G dyes using magnetic biochar derived from the empty fruit bunch (EFB) was carried out. Process parameters such as pH, adsorbent dosage, agitation speed and contact time were optimized using Design-Expert Software v.6.0.8. The statistical analysis reveals that the optimum conditions for the maximum adsorption of MB are at pH 2 and pH 10, dosage 1.0 g, and agitation speed and contact time of 125 rpm and 120 min respectively. While for orange-G, at pH 2, dosage 1.0 g, and agitation speed and contact time of 125 rpm and 120 min respectively. The maximum adsorption capacity of 31.25 mg/g and 32.36 mg/g for MB and orange-G respectively. The adsorption kinetic for both dyes obeyed pseudo-second order.


2014 ◽  
Vol 1004-1005 ◽  
pp. 10-13
Author(s):  
Li Fu ◽  
Mika Matsunaka Sokiransky ◽  
Ai Min Yu

Silver dendrites were synthesized via a simple and straightforward strategy based on the galvanic displacement between Ag ions and aluminum foil in the room temperature. Because the presence of Al2O3thin layer on the surface of aluminum foil, the NaCl was added to accelerates the reaction rate. The formed Ag dendrites was characterized by UV-vis spectroscopy, SEM and XRD. The as-prepared Ag dendrites were developed as a catalyst by mixed with reduced graphene oxide and used for degradation of methylene blue when the presence of NaBH4. Moreover, the optimal conditions of degradation were also investigated.


2012 ◽  
Vol 479-481 ◽  
pp. 250-254
Author(s):  
Wen Jun Xiang

Iron oxides-coated kaolinite (Fe-Kaolinite) was prepared by co-precipitation and indentified using X-ray diffraction (XRD). Moreover, the surface properties and fluoride adsorption characteristics of Fe-Kaolinite were investigated and compared with those of kaolinite. Compared to kaolinite, the BET surface area and surface fractal dimension of Fe-Kaolinite increased significantly. The pH at zero point of charge (pHZPC) of kaolinite and Fe-Kaolinite was 3.16 and 6.24, respectively. In the suspensions of pH 6.0, the fitted maximum adsorption capacity (qmax) for fluoride of kaolinite and Fe-Kaolinite was 1.32 and 5.86 mg/g, respectively. The adsorption data for fluoride by Fe-Kaolinite could be fitted using Freundlich isotherm (R2 =0.987), and Langmuir isotherm was very suitable for describing the fluoride adsorption of kaolinite (R2 =0.991).


2021 ◽  
Vol 10 (2) ◽  
pp. 36-42
Author(s):  
Duyen Le Thi ◽  
Hanh Vo Thi ◽  
Dung Cong Tien ◽  
Thanh Dinh Thi Mai

Hydroxyapatite/chitosan nanocomposite (n-HAp/ChS) was synthesized successfully from 0.5 M Ca(NO3)2 + 5 % chitosan/2 % acetic acid solution and 0.3 M (NH4)2HPO4 solution at pH 10-11 using 28 % NH3 solution by chemical precipitation method. n-HAp/ChS was used for the adsorption of Cd2+ from aqueous solution. The effect of factors on the Cd2+ adsorption efficiency and capacity was investigated. The adsorption efficiency and capacity obtained 97,75 % and 58,65 mg/g respectively at suitable condition: pH0 5.9,n-HAp/ChS mass of 0.1 g, initial Cd2+ concentration of 60 mg/L, contact time 40 minutes at room temperature (30oC). The experimental data was described by Langmuir and Freundlich isotherm models.


2019 ◽  
Vol 20 (7) ◽  
pp. 1609 ◽  
Author(s):  
Vasile Mînzatu ◽  
Corneliu-Mircea Davidescu ◽  
Petru Negrea ◽  
Mihaela Ciopec ◽  
Cornelia Muntean ◽  
...  

The aim of this paper was to produce a new composite material based on carbon and iron oxides, starting from soluble starch and ferric chloride. The composite material was synthesized by simple thermal decomposition of a reaction mass obtained from starch and iron chloride, in an inert atmosphere. Starch used as a carbon source also efficiently stabilizes the iron oxides particles obtained during the thermal decomposition. The reaction mass used for the thermal decomposition was obtained by simultaneously mixing the carbon and iron oxide precursors, without addition of any precipitation agent. The proper composite material can be obtained by rigorously adhering to the stirring time, temperature, and water quantity used during the preparation of the reaction mass, as well as the thermal regime and the controlled atmosphere used during the thermal decomposition. Synthesized materials were characterized using thermogravimetric analysis, X-Ray Diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infra-red spectroscopy (FT-IR). The performances of the obtained material were highlighted by studying their adsorbent properties and by determining the maximum adsorption capacity for arsenic removal from aqueous solutions.


2015 ◽  
Vol 72 (6) ◽  
pp. 896-907 ◽  
Author(s):  
S. M. Anisuzzaman ◽  
Collin G. Joseph ◽  
D. Krishnaiah ◽  
A. Bono ◽  
L. C. Ooi

In this study, durian (Durio zibethinus Murray) skin was examined for its ability to remove methylene blue (MB) dye from simulated textile wastewater. Adsorption equilibrium and kinetics of MB removal from aqueous solutions at different parametric conditions such as different initial concentrations (2–10 mg/L), biosorbent dosages (0.3–0.7 g) and pH solution (4–9) onto durian skin were studied using batch adsorption. The amount of MB adsorbed increased from 3.45 to 17.31 mg/g with the increase in initial concentration of MB dye; whereas biosorbent dosage increased from 1.08 to 2.47 mg/g. Maximum dye adsorption capacity of the durian skin was found to increase from 3.78 to 6.40 mg/g, with increasing solution pH. Equilibrium isotherm data were analyzed according to Langmuir and Freundlich isotherm models. The sorption equilibrium was best described by the Freundlich isotherm model with maximum adsorption capacity of 7.23 mg/g and this was due to the heterogeneous nature of the durian skin surface. Kinetic studies indicated that the sorption of MB dye tended to follow the pseudo second-order kinetic model with promising correlation of 0.9836 < R2 < 0.9918.


2019 ◽  
Vol 948 ◽  
pp. 26-32
Author(s):  
Galuh Yuliani ◽  
Siska Mutiara ◽  
Agus Setiabudi

The amount of coal combustion byproducts, such as fly ash and bottom ash, generated by coal-based thermal power plants has been increasing at an alarming rate, hence creating huge problems on their treatments and disposals. One of the promising approaches for proper utilization of these byproducts is the conversion of fly ash and bottom ash to zeolites. In this research, zeolites wereprepared from coal bottom ash (RBA) by relatively simple and cheap conversion process using NaOH at 90°C for 24h. Prior to this, the RBA was pretreated using H2SO4 for 4h. The resulted zeolite was characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). XRD results confirmed the formation of sodium aluminosilicate hydrate predominated upon the bottom ash and NaOH 5M ratio of 1:8. XRF results also indicated the domination of Al2O3 and SiO2 in the zeolite composition. FTIR spectra showed characteristic zeolite peaks at 900-1100, 400-500 and 550-660 cm–1forSi-O, Al-O, and Si-O-Al absorptions, respectively. The synthetic zeolite was then applied as an adsorbent for lignin and methylene blue in aqueous solutions. It was found that the Qmax for lignin and methylene blue was16.13 mg/g and 34.13 mg/g, respectively. When fitted using Langmuir and Freundlich isotherm models, the methylene blue adsorption data fitted Langmuir isotherm while those of lignin fitted Freundlich isotherm. It was concluded that the chemical interaction between zeolite and methylene blue may lead to the chemisorption mechanism to prevail.


2014 ◽  
Vol 893 ◽  
pp. 166-169 ◽  
Author(s):  
Walaikorn Nitayaphat ◽  
Thanut Jintakosol

Chitosan/CNT nanocomposites were prepared by blending chitosan with carbon nanotubes (CNTs) and forming composite beads. The composites were used as Ag+adsorbents. Adsorption equilibrium experiments were carried out as a function of contact time, CNTs concentration, pH value, and adsorbent dosage level. The equilibrium time of Ag+adsorption was found to be 160 min. Composite adsorbent had the highest adsorption efficiency when the weight of CNTs was 0.01 wt%. The maximum Ag+removal took place at the initial pH value of 3. The optimum adsorbent dosage for Ag+removal was 5 g. Under above optimal conditions the maximum Ag+removal was 99.7%. The adsorption isotherm of chitosan/CNT nanocomposite bead agreed well with the Langmuir model. The maximum adsorption capacity was 0.393 mg/g.


2017 ◽  
Vol 751 ◽  
pp. 671-676 ◽  
Author(s):  
Tawan Chaiwon ◽  
Panatda Jannoey ◽  
Duangdao Channei

This research aimed to study the preparation of activated carbon from sugarcane bagasse waste. The sugarcane bagasse adsorbent was prepared by calcination at 600°C for 2 hours with the use of sulfuric acid (H2SO4) as a chemical activation. The adsorption surface possessed high specific surface area (838 m2/g) with mesoporous diameter. Factors explaining adsorption including adsorption isotherm, adsorption kinetic and adsorption mechanism were constructed from methylene blue adsorption experiments. It was found that the equilibrium data was best represented by Freundlich isotherm, showing multilayer coverage of dye molecules at the outer surface of adsorbent with a cooperative adsorption (physisorption and chemisorption). The kinetic of methylene blue adsorption was found to follow pseudo-second-order rate kinetic model, with a good correlation coefficient. This indicated that the overall rate of the dye adsorption process was controlled by the chemisorption process.


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