scholarly journals Microwave Irradiation Assisted Preparation of Chitosan Composite Microsphere for Dye Adsorption

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaoyu Chen ◽  
Lindun He

Chitosan-activated carbon composite microspheres were prepared by emulsion cross-linking method and its adsorption properties for methyl orange were studied. Chitosan solution was mixed with activated carbon powder and then chitosan was cross-linked by epichlorohydrin under microwave irradiation. SEM photos show that the composite microspheres have diameters of 200–400 μm and activated carbon powder dispersed on the surface of composite microsphere. FTIR spectrum indicates chitosan is successfully cross-linked. Microwave irradiation can effectively shorten the cross-linking time. Composite microspheres have enhanced dye adsorption capacity for methyl orange compared to chitosan microspheres. Kinetic studies showed that the adsorption followed a pseudo-second-order model. Isotherm studies show that the isotherm adsorption equilibrium is better described by Freundlich isotherm. Regeneration results show that adsorption capacity of composite microsphere decreased about 5.51% after being reused for three times. These results indicated that chitosan-activated carbon composite microsphere has potential application in the removal of dye from wastewaters.

2015 ◽  
Vol 25 (3) ◽  
pp. 25-34 ◽  
Author(s):  
Laura Alicia Ramírez Llamas ◽  
Araceli Jacobo Azuara ◽  
J. Merced Martínez Rosales

In this paper, layered double hydroxides (LDH) were synthesized and characterized using techniques of Physisorption of Nitrogen, Infrared, Temperature Programmed Desorption, X-Ray Diffraction, TGA and Immersion Microcalorimetry, in order to determine the basic properties of the adsorbent. The methyl orange (MO) is used as a dye and as a result, it is frequently found in effluents from textile industries. The dye adsorption isotherms on LDH were studied as function of pH and temperature. The maximum adsorption capacity of methyl orange on LDH was carried out at pH 5, and the minimum adsorption capacity at pH 11, being 40.2 mg/g and 22.1 mg/g, respectively. Furthermore, the suitable temperature to promote the adsorption of methyl orange on LDH was at 25 °C, as at 35 °C shows a significant decrease. 


2000 ◽  
Vol 42 (5-6) ◽  
pp. 355-362 ◽  
Author(s):  
H. Pignon ◽  
C. Brasquet ◽  
P. Le Cloirec

The aim of this work is to evaluate the efficiency of Activated Carbon Cloths (ACCs) as a refining treatment of membrane filtration in the case of effluent streams containing both dyes and suspended solids (SS) or colloids responsible for turbidity. It is divided into two parts. First, dye adsorption experiments are carried out. Kinetics and isotherms enable us to show the feasibility of the adsorption and to study the influence of different operating conditions. The results demonstrate that adsorption is enhanced under acidic conditions, the adsorption capacity being increased by 40% in some cases. Moreover, microscopic characteristics of ACCs have a great influence on the adsorption process: there is a relationship between the adsorbent porosity and the adsorbate molecular weight, the mesoporous adsorbent being more efficious to remove the larger molecular weight dyes. In the case of low molecular weight compounds, the adsorbent with the higher specific surface area provides the greater adsorption capacity. Molecular connectivity indexes were used to confirm the correlation of the molecular structure of the adsorbates with their adsorbability. The second part consists of an estimation of the efficiency of the coupling of ultrafiltration and adsorption onto ACC. Tests performed on a laboratory-scale coupling show that a molecular weight cut-off of 3,000 D gives rise to a 98% removal of turbidity whereas dyes are not much retained. Furthermore, ultrafiltration is useful in improving the adsorption capacities of ACC in a continuous flow reactor (up to 50%).


2019 ◽  
Vol 6 (5) ◽  
pp. 182226 ◽  
Author(s):  
Jian Meng ◽  
Jianlan Cui ◽  
Siyuan Yu ◽  
Hui Jiang ◽  
Congshan Zhong ◽  
...  

Polyamine chelating adsorbents have a good removal effect on dye wastewater. In this study, small molecule triethylenetetramine and macromolecular poly(ethylene imine) were selected as aminated reagent, and two kinds of aminated chitosan microspheres, TETA-CTSms and PEI-CTSms, were obtained by emulsion cross-linking method. The microspheres were fully characterized by FTIR, SEM, XRD, EDS and TGA. EDS results showed that the N content of the PEI-CTSms and TETA-CTSms microspheres increased significantly after the cross-linking reaction and can reach 5.7 wt% and 7.3 wt%, respectively. Adsorption experiments confirmed that TETA-CTSms and PEI-CTSms showed greater adsorption characteristics for anionic dye reactive yellow (RY) in aqueous solutions compared with CTSms, and the adsorption capacity per unit area was increased by 39.11% and 88.56%, respectively. The adsorption capacity of aminated microspheres for RY decreased with the increase of pH. The adsorption kinetics conformed to the pseudo-second-order model, and the adsorption process was in accordance with the Langmuir isotherm model. The negative value of Δ G confirmed that the adsorption process was spontaneous, and the dye adsorption was a multiple process dominated by chemical chelating and physical adsorption.


Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 372 ◽  
Author(s):  
Lipei Fu ◽  
Jiahui Zhu ◽  
Weiqiu Huang ◽  
Jie Fang ◽  
Xianhang Sun ◽  
...  

Carbon-silica composites with nanoporous structures were synthesized for the adsorption of volatile organic compounds (VOCs), taking tetraethyl orthosilicate (TEOS) as the silicon source and activated carbon powder as the carbon source. The preparation conditions were as follows: the pH of the reaction system was 5.5, the hydrophobic modification time was 50 h, and the dosage of activated carbon was 2 wt%. Infrared spectrum analysis showed that the activated carbon was dispersed in the pores of aerogel to form the carbon-silica composites material. The static adsorption experiments, dynamic adsorption-desorption experiments, and regeneration experiments show that the prepared carbon-silica composites have microporous and mesoporous structures, the adsorption capacity for n-hexane is better than that of conventional hydrophobic silica gel, and the desorption performance is better than that of activated carbon. It still has a high retention rate of adsorption capacity after multiple adsorption-desorption cycles. The prepared carbon-silica composites material has good industrial application prospects in oil vapor recovery, providing a new alternative for solving organic waste gas pollution.


2014 ◽  
Vol 625 ◽  
pp. 106-109 ◽  
Author(s):  
Maimoon Sattar ◽  
Fareeda Hayeeye ◽  
Watchanida Chinpa ◽  
Orawan Sirichote

Polysulfone/Activated Carbon (PSF/AC) composites in bead form were prepared for Rhodamine B sorption. The scanning electron microscope (SEM) shows that pure PSF bead is smooth surface while PSF/AC bead presents the pore distribution. FT-IR spectra indicate the existence of AC on the PSF/AC bead surface. Under adsorption test of Rhodamine B, it was found that an increase in the AC content in PSF solution results in an increase in the percentages of dye adsorption from 1.38 % to 71.56% for pure PSF bead and PSF/AC added with 4 wt% of AC, respectively.


2019 ◽  
Vol 8 (1) ◽  
pp. 1-9
Author(s):  
Dilma Purnama Ubit ◽  
Yusmaniar Yusmaniar ◽  
Erdawati Erdawati

Abstrak Pada penelitian ini adsorben komposit silika mesopori dan karbon aktif dibuat untuk mengadsorpsi zat warna direct black 38. Silika mesopori dibuat dari abu sekam padi dan karbon aktif dibuat dari tempurung kelapa. Silika direaksikan dengan NaOH menjadi larutan natrium silikat lalu direaksikan dengan PEG yang selanjutnya PEG diekstraksi secara solvotermal sehingga menghasilkan produk silika mesopori dengan luas permukaan dan pori yang lebih besar. Silika mesopori diproses menjadi komposit dengan karbon aktif yang telah diaktivasi sebelumnya dengan larutan ZnCl2. Kandungan dari komposit silika mesopori/karbon aktif ditunjukkan melalui hasil analisis SEM bahwa komposit hasil sintesis menunjukkan penyebaran karbon dan silika terlihat pada morfologi komposit. Hasil analisis EDX menunjukan komponen penyusun komposit yaitu 38,6% karbon; 46,8% oksigen dan 14,6% silika. Hasil penelitian menunjukan bahwa kondisi optimum yang diperlukan untuk adsorpsi direct black 38 dengan komposit silika mesopori/karbon aktif yaitu pH 2 dan waktu optimum 30 menit. Adsorpsi direct black 38 oleh komposit silika mesopori/karbon aktif mengikuti isoterm adsorpsi Langmuir. Oleh karena itu, adsorpsi yang terjadi membentuk lapisan monolayer dengan kapasitas adsorpsi 68,493 mg g-1 Kata kunci: abu sekam padi, adsorpsi, karbon aktif, komposit, PEG, silika mesopori Abstract In this research, mesopore silica/activated carbon composite adsorbent was formed for dye adsorption direct black 38. The mesopore silica was from rice husk ash and activated carbon was from coconut shell. This rice husk ash is processed into sodium silicate solution and the solution was hybrid with PEG. Then PEG was extracted with solvotermal method to produce a higher surface area of mesopore silica. The mesopore silica was processed                         into composite with activated carbon that has been activated by ZnCl2 solution. The mesopore silica/activated carbon composite was analysed by SEM and showed the distribution of carbon, silica and oxygen as composite morphology. The EDX analysis showed that the composite contains of 46.8% carbon; 3.6% oxygen and 14.6% silica. The results showed that the optimum condition required for the adsorption of direct black 38 dye with mesopore silica/activated carbon composite pH was 2 and the optimum contact time was 30 minutes. Adsorption of direct black 38 by mesopore silica/activated carbon composite followed Langmuir adsorption isotherm and formed a monolayer layer with adsorption capacity 68.493 mg g-1.   Keywords: activated carbon, adsorption, composite, mesopore silica, PEG, rice husk ash Abstrak Pada penelitian ini adsorben komposit silika mesopori dan karbon aktif dibuat untuk mengadsorpsi zat warna direct black 38. Silika mesopori dibuat dari abu sekam padi dan karbon aktif dibuat dari tempurung kelapa. Silika direaksikan dengan NaOH menjadi larutan natrium silikat lalu direaksikan dengan PEG yang selanjutnya PEG diekstraksi secara solvotermal sehingga menghasilkan produk silika mesopori dengan luas permukaan dan pori yang lebih besar. Silika mesopori diproses menjadi komposit dengan karbon aktif yang telah diaktivasi sebelumnya dengan larutan ZnCl2. Kandungan dari komposit silika mesopori/karbon aktif ditunjukkan melalui hasil analisis SEM bahwa komposit hasil sintesis menunjukkan penyebaran karbon dan silika terlihat pada morfologi komposit. Hasil analisis EDX menunjukan komponen penyusun komposit yaitu 38,6% karbon; 46,8% oksigen dan 14,6% silika. Hasil penelitian menunjukan bahwa kondisi optimum yang diperlukan untuk adsorpsi direct black 38 dengan komposit silika mesopori/karbon aktif yaitu pH 2 dan waktu optimum 30 menit. Adsorpsi direct black 38 oleh komposit silika mesopori/karbon aktif mengikuti isoterm adsorpsi Langmuir. Oleh karena itu, adsorpsi yang terjadi membentuk lapisan monolayer dengan kapasitas adsorpsi 68,493 mg g-1 Kata kunci: abu sekam padi, adsorpsi, karbon aktif, komposit, PEG, silika mesopori Abstract In this research, mesopore silica/activated carbon composite adsorbent was formed for dye adsorption direct black 38. The mesopore silica was from rice husk ash and activated carbon was from coconut shell. This rice husk ash is processed into sodium silicate solution and the solution was hybrid with PEG. Then PEG was extracted with solvotermal method to produce a higher surface area of mesopore silica. The mesopore silica was processed into composite with activated carbon that has been activated by ZnCl2 solution. The mesopore silica/activated carbon composite was analysed by SEM and showed the distribution of carbon, silica and oxygen as composite morphology. The EDX analysis showed that the composite contains of 46.8% carbon; 3.6% oxygen and 14.6% silica. The results showed that the optimum condition required for the adsorption of direct black 38 dye with mesopore silica/activated carbon composite pH was 2 and the optimum contact time was 30 minutes. Adsorption of direct black 38 by mesopore silica/activated carbon composite followed Langmuir adsorption isotherm and formed a monolayer layer with adsorption capacity 68.493 mg g-1.   Keywords: activated carbon, adsorption, composite, mesopore silica, PEG, rice husk ash  


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